Reifenstuhl, R.R. Dover, J.H. Newberry, R.J. Clautice, K.H. Pinney, D.S. Liss, S.A. Blodgett, R.B. Weber, F.R. 1998 map and vector digital data Public Data File PDF 98-37A v 1.1 Fairbanks, AK, USA State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) text report, 19 p., 1 sheet, scale 1:63,360 http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=1863 This report provides detailed (1:63,360-scale) mapping of the Tanana A-1 and A-2 quadrangles (500 square miles; equivalent to eight 7.5-minute quadrangles). The area is part of the Manley Hot Springs-Tofty mining districts and adjacent to the Rampart mining district to the south of the Tanana B-1 Quadrangle. This report includes detailed bedrock, surficial, structural, and stratigraphic data. Based on the resulting geologic maps, field investigations, and laboratory materials analyses, the report also includes derivative maps of geologic construction materials and geologic hazards. The Tanana A-1 and A-2 Quadrangles and surrounding area comprise several isolated mountainous ridges in the western Yukon-Tanana Upland of interior Alaska. The Tanana A-1 and A-2 quadrangles lie between the villages of Rampart, on the Yukon River, and Manley Hot Springs, at the terminus of the Elliott Highway. At the time the report was published, the area towns were not part of any municipal or local governmental jurisdiction. The investigation of gold, tin, and other mineral occurrences in conjunction with comprehensive geologic mapping and recently-acquired geophysical data will provide a scientific basis for expanded mineral exploration and development that can lead to the economic growth and the creation of new jobs needed by the Rampart-Manley-Tofty region's inhabitants and the State of Alaska. These objectives are consistent with the statewide goals and priorities articulated for the Department of Natural Resources by Alaska's Governor in his Executive Budget Summary for Fiscal Year 1997. The layers listed below are present as ArcGIS shape files. Attribute information for the following layers (entities) is included in this metadata file under the "Entity_and_Attribute_Information" section. Each layer is listed and described in detail under its own heading starting "Entity_Type_Label." The numerical value(s) "1" and/or "2" included in the layer names correspond to the quadrangle(s) Tanana A-1 and/or Tanana A-2, respectively. Layers include: >hflsa1_comp_polygon comprehensive geologic unit polygons (hornfels) >hflsa2_comp_polygon comprehensive geologic unit polygons (hornfels) >tana12_att_point points for the strike, dip, and plunge of bedding planes, foliation, and various lineaments >tana1bedcon_arc comprehensive geologic unit contacts >tana1bur_arc vector lines for various types of geophysical features >tana1comp_polygon comprehensive geologic unit polygons >tana1fld_point points and vector lines for types of anticlines or synclines >tana1fldline_arc types of folds, anticlines, synclines, or lines depicting a cross-section >tana1srf_polygon comprehensive geologic polygons >tana1strline_arc vector lines for types of faults >tana2bedcon_arc comprehensive geologic unit contacts >tana2bur_arc vector lines for various types of geophysical features >tana2comp_polygon comprehensive geologic unit polygons >tana2fld_point points and vector lines for types of anticlines or synclines >tana2fldline_arc types of folds, anticlines, synclines, or lines depicting a cross-section >tana2srf_polygon comprehensive geologic polygons >tana2strline_arc vector lines for types of faults 1997 1998 publication date Complete none planned -151.018782 -149.971866 65.259054 64.990820 ISO 19115 Topic Category geoscientificInformation none 40Ar/39Ar Aerial Photography Aeromagnetic Map Aeromagnetic Survey Age Dates Bibliography Biostratigraphy Carbonates Cerium CIPW Norms Clastics Conductivity Survey Core Logs Cultural Resources Depositional Environment Diagenesis Disseminated Economic Geology Economic Study Electromagnetic Survey Epithermal Erosion Faulting Folding Fossils Geologic Map Geomorphology Geophysical Map Glacial Glacial Processes Gold Greenschist Greisen Historic Resources Hot Springs K-Ar Lab Methods Lode Magnetic Susceptibility Magnetometer Survey Major Oxides Marine Measured Stratigraphic Section Metamorphic Grade Metamorphism Mineralogy Mining Modal Analysis Niobium Ores Orogeny Paleobotany Paleocurrent Paleoenvironment Paleontology Palynology Petrogenesis Petrography Petrology Placer Plutonic Plutonic Hosted Precious Metals Production Data Provenance Rare Earth Elements Reconstructions Regional Regional Metamorphism Remote Sensing Resistivity Survey Resource Assessment Sandstone Sedimentary Sedimentation Shale Silver Structure Structure Map Surficial Tectonic Map Tectonics Terranes Topographic Map Turbidites Type Section Uplift Volcanic Volcanic Hosted None Manley Basin Yukon River None Amy Creek Assemblage Hot Springs Pluton Livengood Dome Chert Wickersham Unit Wilber Creek Ash Wolverine Creek Sequence None Cambrian Carboniferous Cenozoic Cretaceous Devonian Famennian Holocene Jurassic Mesozoic Mississippian Ordovician Paleozoic Permian Pleistocene Proterozoic Quaternary Silurian Tertiary Triassic This report, map, and/or dataset are available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below). Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys GIS Data Manager/Cartographer mailing and physical

3354 College Road

Fairbanks AK 99709-3707 (907) 451-5029 (907) 451-5020 (907) 451-5050 dggspubs@alaska.gov You may view our web site at http://www.dggs.dnr.state.ak.us for the latest information on available data. Please e-mail your questions and data requests when possible since our web site and e-mail address will remain current even if our phone number and mailing address change. Funding for the geologic mapping and geochronologic dating performed for this project was provided by the U.S. Geological Survey STATEMAP Program under award number 03HQAG0055 and by the Alaska State Legislature. Microsoft Windows XP SP2, ArcGIS 9.+, and any text editor. Reifenstuhl, R.R. Dover, J.H. Newberry, R.J. Clautice, K.H. Liss, S.A. Blodgett, R.B. Weber, F.R. 1998 map and vector digital data Public Data File PDF 98-37B Fairbanks, AK, USA State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) 17 p., 1 sheet, scale 1:63,360 http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=1864 Pinney, D.S. 1998 map and vector digital data Public Data File PDF 98-37C Fairbanks, AK, USA State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys 1 sheet, scale 1:63,360 http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=1865 Pinney, D.S. 1998 map and vector digital data Public Data File PDF 98-37D Fairbanks, AK, USA State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys 1 sheet, scale 1:63,360 http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=1866 Location data for geologic and comprehensive point data were entered manually from GPS units into a spreadsheet. Data for surficial and materials point, line, and polygon data were determined in the field using 1:63,360-scale topographic maps and 1:50,000 (nominal) scale, color-infrared aerial photographs. Geologic data included in the compilation are the field maps and notes from this project as well as data from other sources as noted in the "Sources Cited" section. Attributes were verified for consistency and completeness during the creation of the metadata. Polygon topology present and clean on appropriate data. Other data are line, point, or annotation data and do not require topologic relationships. This dataset includes geospatial information about geologic units, their ages, field sample locations, structural features, structural measurements, and geology interpreted from airborne geophysics. DGGS location data and estimated position errors were manually entered into a spreadsheet. Sample numbers and locations with selected data were spatially registered and analyzed in ArcGIS software. Location data for the surficial and materials maps were determined visually using topographic maps at a scale of 1:63,360 and 1:50,000 (nominal) scale, color-infrared aerial photographs. See "Source_Information" section for horizontal positional accuracy of locations not measured by DGGS. 100 A value of estimated position error in meters was calculated by the GPS units and recorded for each sample location. This error results from items such as error in satellite positions, mathematical error introduced by the formulas used by the GPS unit for calculating position, and errors caused by narrow satellite alignments. Estimated position error is a value determined by the GPS manufacturer for the calculation and geometric error as a whole. "Selective availability," a deliberate degradation of GPS data managed by the U.S. government that induces an additional error of approximately 100 meters to a GPS location, was in effect until May 1, 2000, and thus during the time of this field work. 110 A value of estimated position error in meters. Surficial and bedrock geologic map data have a horizontal positional accuracy dependent on: 1) the 1:50,000-scale (nominal) aerial photographs on which it is based, with an estimated potential error due to a pen line width of approximately 0.001 being equivalent to approximately 1.5 meters on the ground; 2) the accuracy of the human zoom transfer scope operator in tracing the line work from acetate overlays to topographic base maps, with an estimated error due to a pen line width of approximately 0.001 being equivalent to approximately 1.5 meters on the ground; 3) the accuracy of the zoom transfer process itself, error magnitude highly variable and unknown but potentially large; 4) the digitizing RMS error of 0.003 inches (input coverage units), which equates to approximately 5 meters on the ground for a 1:63,360-scale map; and 5) the accuracy of the human operator digitizing the geologic from the topographic base maps, with an estimated error due to a pen line width of approximately 0.001 being equivalent to approximately 1.5 meters on the ground. The bedrock and comprehensive field maps were digitized using a map tablet and cross-hair mouse. Map error is induced by: (1) transferring map data from base topography to a mylar compilation map, with an estimated potential error due to a pen line width of approximately 0.001 being equivalent to approximately 1.5 meters on the ground; (2) the digitizing RMS error [24 control points on a regular grid have an average RMS error of 10.8 meters on the ground; individual control point error ranges from 4.3 to 21.2 meters on the ground]; and (3) the accuracy of the human operator digitizing the geologic line work from the topographic base map, with an estimated error due to a pen line width of approximately 0.001 being equivalent to approximately 1.5 meters on the ground. Total potential horizontal error for bedrock and comprehensive geologic map features is estimated to be approximately 110 meters. Eakin, H.M. 1912 U.S. Geological Survey Bulletin Bulletin 520 Reston, VA, USA U.S. Geological Survey p. 271-286 paper 1912 publication date Eakin, 1912 This map contains geologic unit descriptions and outcrop locations and was used to plan traverses and help define geologic units. Eakin, H.M. 1913 U.S. Geological Survey Bulletin Bulletin 535 Reston, VA, USA U.S. Geological Survey p. 38 paper 1913 publication date Eakin, 1913 This map contains geologic unit descriptions and outcrop locations and was used to plan traverses and help define geologic units. Hopkins, D.M. Taber, B. 1962 Special Paper v. 68 Boulder, CO, USA Geological Society of America p. 116 paper 1962 publication date Hopkins and Taber, 1962 This map contains geologic unit descriptions and outcrop locations and was used to plan traverses and help define geologic units. Newberry, R.J. Clautice, K.H. 1997 Public Data File PDF 97-49 Fairbanks, AK, USA State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) p. 49 http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=1813 paper 1997 publication date Newberry and Clautice, 1997 This report contains information that was used to aid in the creation of and sample preparation for the surficial geologic map (PDF 98-37C). Wagner, A.A. 1957 Proceedings v. I London, England 4th International Conference on Soil Mechanics and Foundation Engineering p. 125 paper 1957 publication date Wagner, 1957 This report contains information that was used to aid in the creation of and sample preparation for the surficial and geologic materials map (PDF 98-37C and PDF 98-37D). Yeend, W.E. 1989 U.S. Geological Survey Bulletin Bulletin 1946 Reston, VA, USA U.S. Geological Survey p. 107-109 paper 1989 publication date Yeend, 1989 This report contains information that was used to aid in the creation of and sample preparation for the surficial geologic map (PDF 98-37C). Field work - Field work for bedrock investigations, including ridge traverses and examination of riverbank exposures, was conducted between June 16 and July 8, 1997. Field notes and rock samples were collected at approximately 700 stations throughout the Tanana A-1 and A-2 Quadrangles. Bedrock mappers recorded observations on 1:50,000- and 1:63,360-scale topographic base maps, compiled onto a 1:50,000-scale mylar map after the field season ended. Field stations were located using hand held GPS units. Field station notes and GPS location data were manually entered into a spreadsheet. 1997 Fieldwork - Fieldwork for surficial geologic investigations, including ridge and valley traverses, road cut investigations, and river exposures, was conducted for approximately 21 person-days in June and July 1997 by a surficial geologist. Field notes and sediment samples were collected throughout the area for surficial investigations. Surficial mapping involved using sources cited below on a regular basis for checking and correlating general units. The surficial mapper recorded observations on co-registered acetate overlays on 1:50,000-scale (nominal) color-infrared aerial photographs, and directly on 1:63,360-scale topographic base maps. Stations were located using air photos and topographic maps. Eakin, 1912 Eakin, 1913 Hopkins and Taber, 1962 Newberry and Clautice, 1997 Yeend, 1989 1997 Laboratory data - See paper reports PDF 98-37A and PDF 98-37B for more information. 1997 Photo interpretation - Before, during, and after field work, surficial-geologic information was interpreted using 1:50,000-scale (nominal) color-infrared air-photo stereopairs, and compiled onto acetate overlays. Photo interpretation was based on field notes from fieldwork process step (above), observed land forms and relationships in the photos, and all known geologic data from previous work in the area. The main sources of existing data include Eakin (1912; 1913), Hopkins and Tabor (1962), and Yeend (1989). The overlay information was transferred to a paper 1:63,360-scale USGS topographic base using a zoom transfer scope. Eakin, 1912 Eakin, 1913 Hopkins and Taber, 1962 Newberry and Clautice, 1997 Yeend, 1989 1997 Digital Cartography - Surficial-geologic information was digitized from the paper USGS topographic base map into Arc/Info 7.0.4 GIS (ArcEdit module) using a large-format digitizing table. Surficial-geologic polygons and lines were then edited and attributed using Arc, Info, and ArcEdit. Bedrock point data of locations of structural observations (strike, dip, cleavage, jointing, etc.) were intersected with the surficial-geologic polygon coverage using the Arc command "intersect" in order to identify locations that were mapped as surficial materials based on aerial photography but were found to have small exposures that were desirable to be mapped as bedrock. These areas were then modified in the surficial-geologic coverages to be areas of bedrock exposure. Final bedrock and surficial geology polygon coverages were merged using the Arc command "union" to generate the polygon coverage used to make the comprehensive geologic map. Other cartographic elements, primarily text and tables, were created in CorelDraw, converted to CGM format, and imported into ArcPlot for final layout. Data from the comprehensive geologic map of the area were used as the basis for generating the derivative engineering-geologic map. An ArcInfo lookup table was made to assign geologic units (item UNIT) from the comprehensive map to appropriate engineering-geologic units (item MAT) based on the Unified Soil Classification System as described by Wagner (1957). This lookup table was applied to the ArcInfo polygon coverage containing the geologic units and a new engineering-geologic polygon coverage was generated using the "dissolve" command based on the new materials-unit item "MAT." Additional features were mapped from ground observations and interpretation of air photos, and digitized and attributed using ArcInfo. ArcPlot was used to generate plot files of the resulting materials coverage using DGGS-standard symbology. Wagner, 1957 1997 Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana1comp_polygon Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana2comp_polygon Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters hflsa1_comp_polygon Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters hflsa2_comp_polygon Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana1bedcon_arc Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana2bedcon_arc Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana1strline_arc Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana2strline_arc Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana1srf_polygon Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana2srf_polygon Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana1fld_point Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana2fld_point Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana1fldline_arc Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana2fldline_arc Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000005 0.000005 meters tana1bur_arc Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000032 0.000032 meters tana2bur_arc Universal Transverse Mercator 5 0.999600 -153.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000064 0.000064 meters tana12_att_point D_Clarke_1866 Clarke 1866 6,378,206.4 294.978698 tana1comp_polygon.shp Object type is vector, there are 1064 rows associated with this entity, and the entity values refer to comprehensive geologic polygons Alaska Division of Geological & Geophysical Surveys tana1comp_polygon BUNIT Interpretive geologic map unit labels Alaska Division of Geological & Geophysical Surveys Kwcv Wilber Creek unit siliciclastic and volcaniclastic rocks (late Albian(?): Weber and others, 1992)-Very dark gray to dark greenish dark gray, volcanic clast-bearing, poorly sorted, sub-angular, medium- to coarse-grained, marine, argillaceous lithic sandstone, shale and siltstone. Estimates of the framework grain composition are: 55 percent chert, 25 percent quartz, 15 percent plagioclase (which includes about 5 percent obvious volcanic clasts), and 5 percent sedimentary and metamorphic rock fragments, and minor white mica. Alaska Division of Geological & Geophysical Surveys Kwcs Wilber Creek unit sandstone, shale, siltstone, undivided (Albian: Weber and others, 1992)-Very dark gray to dark greenish gray, poorly sorted, marine, argillaceous lithic sandstone, shale and siltstone containing white mica-bearing argillaceous sandstone as laminae and thin interbeds; rare conglomerate. Beds are typically thin, parallel, laterally continuous, sharp-based, and graded; from fine- to medium-grained at the base, grading up to silt at the top of beds. Alaska Division of Geological & Geophysical Surveys KJwq Wolverine quartzite unit (Early Cretaceous and Late Jurassic: Weber and others, 1992)-Very light gray to tan, white- to medium gray-weathering, moderately well sorted, sub-rounded, fine- to medium-grained quartzite, and sublitharenite with interbedded shaley rocks. Estimates of sandstone clast composition indicate greater than 90 percent quartz (rare light-blue color), two to five percent chert, and locally trace amounts of feldspar and white mica. Alaska Division of Geological & Geophysical Surveys KJws Wolverine quartzite unit sandstone and shale-undivided (Early Cretaceous and Late Jurassic: Weber and others, 1992)-Medium gray to light gray, locally black, lichen-covered, quartz-rich sandstone and interbedded shale. Sandstone is silica-cemented, well indurated quartzarenite but lacks the prominent outcrop pattern, continuity, and thickness of the quartzite unit (map unit 'KJwq'). Alaska Division of Geological & Geophysical Surveys TrPs ***Note: typographical error exists on the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1). Unit TrPa does not exist. Unit label should read TrPs.*** Argillite, sandstone and shale (Triassic and Permian: Reifenstuhl and others, 1997a)-Dark gray to very dark gray, typically fine- to very fine-grained, argillaceous siliciclastic rocks, with common orange-brown weathering surfaces. Rocks have a better developed low-grade metamorphic fabric (phyllitic) compared to the Cretaceous to Jurassic age sandstone and shale lithologies above (map units 'KJwq', 'KJws'). Alaska Division of Geological & Geophysical Surveys TrPp Conglomerate (Triassic and Permian: Reifenstuhl and others, 1997a)-Very dark gray, orange-brown-weathering, matrix-supported, chert-pebble to cobble conglomerate. Matrix is dark gray argillite to very fine sand, and clasts are sub-rounded pebble to cobble size. Alaska Division of Geological & Geophysical Surveys Mg Globe quartzite unit (Mississippian: Weber and others, 1992; Mortensen and Thompson, 1990)-Light gray, light- to medium-gray weathering and iron-stained, fine- to medium-grained, bimodal to moderately sorted, distinctive vitreous quartzite, with interbedded medium to dark gray slate, phyllite, and shaley rocks. Framework grains are well rounded to sub-rounded monocrystalline quartz, and minor chert clasts. Alaska Division of Geological & Geophysical Surveys Dl Devonian limestone fault slivers at Granite Creek [Famennian (late Late Devonian): this report]-Dark gray, light gray-weathering, lime mudstone. Uppermost strata of the largest fault sliver include abundant floating quartz grains up to 3 mm in diameter, which are increasingly abundant down-section. Alaska Division of Geological & Geophysical Surveys Dc Conglomerate (Late Devonian?: this report)-Dark gray to very dark gray, brown-weathering, clast-supported, chert-pebble to cobble conglomerate; matrix consists of siliciclastic and carbonate material, and clasts are sub-rounded pebble to cobble size. Alaska Division of Geological & Geophysical Surveys Pzlca Chert and cherty argillite (Ordovician)-Heterogeneous unit composed dominantly of light gray to gray, thinly laminated, recrystallized sericitic chert and siliceous argillite, commonly with phyllitic argillite partings; 'cherty argillite' typically has cherty or mylonitic aspect on weathered surfaces, but fine-grained elastic or recrystallized texture on fresh surfaces. Alaska Division of Geological & Geophysical Surveys Pzlv Volcanic unit (Ordovician)-Greenish-gray, chloritic and feldspathic rocks and greenstone. Protolith of volcanic rocks is volcaniclastic, tuffaceous, and flow rocks of basaltic to intermediate composition. Some rocks are diabasic and may be meta-intrusive rocks; the number of metavolcanic layers is uncertain. Alaska Division of Geological & Geophysical Surveys Pzlo Orum limestone (Middle Ordovician to Neoproterozoic: informal name, Hopkins and Taber, unpublished manuscript)-Light to medium gray, tan to reddish brown-weathering, extensively recrystallized, typically thin- to medium-bedded lime mudstone. Unit is locally thick-bedded, and locally includes ooid grainstones and cryptalgal lamination. Alaska Division of Geological & Geophysical Surveys Ofc Fossil Creek volcanics (Late to Early Ordovician: Weber and others, 1992)-Heterogeneous assemblage of basalt, agglomerate, volcaniclastic conglomerate, lime wackestone, calcareous feldspathic sandstone, shale, siltstone, chert, slate, and phyllite. Alaska Division of Geological & Geophysical Surveys PzPad Dolostone and limestone-White to light gray, massive-bedded, locally laminated, siliceous dolostone and medium gray to dark gray lime mudstone, in approximately equal amounts. Dolostone is typically extensively silicified and characterized by box-work silica network. Alaska Division of Geological & Geophysical Surveys PzPag Greenstone-Dark greenish gray, massive to well foliated, locally magnetic greenstone, amygdaloidal greenstone, and agglomeratic greenstone; basaltic to intermediate composition. Contains calcite amygdule fillings, locally abundant pyrite cubes, and slightly stretched volcanic and carbonate clasts up to cobble size. Alaska Division of Geological & Geophysical Surveys PzPac Cherty argillite and chert-Heterogeneous unit of dominantly black to dark gray chert and siliceous to carbonaceous argillite with well developed phyllitic to subphyllitic slate-like cleavage, and containing one or more dark gray limestone layers or lenses. The geochemical signature of this unit is typical of the chert in the Amy Creek unit (Haug and others, 1997) of Weber and others (1988). Alaska Division of Geological & Geophysical Surveys PzPwg Siliciclastic rock-Medium gray, tan-weathering, thin-bedded, fine-grained argillaceous sandstone, siltstone, rare greenstone (?), and phyllitic argillite. Locally, these rocks include up to 30 percent calcite that likely represents recrystallized matrix. Black, non-calcareous, carbonaceous, phyllitic argillite interbeds and partings are common. Alaska Division of Geological & Geophysical Surveys Tg Hot Springs granite pluton (58 Ma) - Medium- to coarse-grained biotite granite and rare tourmaline-biotite granite. Outcrops as subdued, blocky rubble or a brown gruss. The dominant textural variety contains coarse-grained potassium feldspar (30 percent) in a matrix of medium-grained smoky quartz (30 percent), albitic plagioclase (30 percent), and slightly chloritized biotite (10 percent). Alaska Division of Geological & Geophysical Surveys Kmzd Monzodiorite- Black and white 'peppered', medium-grained, subequigranular, alkalic plutonic rock lacking quartz and with more plagioclase than alkali feldspar. Mafic minerals (clinopyroxene > biotite > hornblende) commonly make up more than 50 percent of the rock. Alaska Division of Geological & Geophysical Surveys JRc Carbonatite - (approximately 200 Ma) Medium- to coarse-grained, dolomite-calcite-magnetite-apatite-rich rock, which weathers to a deep red gossan and is characterized by an intense magnetic high. Occurs as two steeply dipping sills (?) up to 30 m thick, which may be a single sill or dike that is repeated by isoclinal folding. Alaska Division of Geological & Geophysical Surveys SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock- bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels. Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Flood plain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qag Old, high-level alluvial gravels - Irregular residual deposits of gold-bearing, pebble-cobble gravel with well rounded quartzite boulders up to 3 m diameter preserved on high interfluves in the Eureka Creek area; up to 4 m thick, but generally much thinner; locally extensively reworked by mining activity Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qld Delta deposits - Fan-shaped, heterogeneous mixture of well sorted silt, sand, and gravel; thick to thin bedded; shows cross-bedding and fining-upward cycles; surface smooth, except for numerous shallow, interconnected channels. Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys WATER body of water Alaska Division of Geological & Geophysical Surveys UNIT Generic geologic map unit labels Alaska Division of Geological & Geophysical Surveys Kwcv Wilber Creek unit siliciclastic and volcaniclastic rocks (late Albian(?): Weber and others, 1992) - Very dark gray to dark greenish dark gray, volcanic clast-bearing, poorly sorted, sub-angular, medium- to coarse-grained, marine, argillaceous lithic sandstone, shale and siltstone. Estimates of the framework grain composition are: 55 percent chert, 25 percent quartz, 15 percent plagioclase (which includes about 5 percent obvious volcanic clasts), and 5 percent sedimentary and metamorphic rock fragments, and minor white mica. Alaska Division of Geological & Geophysical Surveys Kwcs Wilber Creek unit sandstone, shale, siltstone, undivided (Albian: Weber and others, 1992) - Very dark gray to dark greenish gray, poorly sorted, marine, argillaceous lithic sandstone, shale, and siltstone containing white mica-bearing argillaceous sandstone as laminae and thin interbeds; rare conglomerate. Beds are typically thin, parallel, laterally continuous, sharp-based, and graded; from fine to medium grained at the base, grading up to silt at the top of beds. Alaska Division of Geological & Geophysical Surveys KJwq Wolverine quartzite unit (Early Cretaceous and Late Jurassic: Weber and others, 1992) - Very light gray to tan, white- to medium gray-weathering, moderately well sorted, subrounded, fine- to medium-grained quartzite, and sublitharenite with interbedded shaley rocks. Estimates of sandstone clast composition indicate greater than 90 percent quartz (rare light-blue color), two to five percent chert, and locally trace amounts of feldspar and white mica. Alaska Division of Geological & Geophysical Surveys KJws Wolverine quartzite unit sandstone and shale-undivided (Early Cretaceous and Late Jurassic: Weber and others, 1992) - Medium gray to light gray, locally black, lichen-covered, quartz-rich sandstone and interbedded shale. Sandstone is silica-cemented, well-indurated quartzarenite but lacks the prominent outcrop pattern, continuity, and thickness of the quartzite unit (map unit 'KJwq'). Alaska Division of Geological & Geophysical Surveys TrPs ***Note: typographical error exists on the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1). Unit TrPa does not exist. Unit label should read TrPs.*** Argillite, sandstone and shale (Triassic and Permian: Reifenstuhl and others, 1997a) - Dark gray to very dark gray, typically fine to very fine grained, argillaceous siliciclastic rocks, with common orange-brown weathering surfaces. Rocks have a better developed low-grade metamorphic fabric (phyllitic) compared to the Cretaceous to Jurassic age sandstone and shale lithologies above (map units 'KJwq', 'KJws'). Alaska Division of Geological & Geophysical Surveys TrPp Conglomerate (Triassic and Permian: Reifenstuhl and others, 1997a) - Very dark gray, orange-brown-weathering, matrix-supported, chert-pebble to cobble conglomerate. Matrix is dark gray argillite to very fine sand, and clasts are sub-rounded pebble to cobble size. Alaska Division of Geological & Geophysical Surveys Mg Globe quartzite unit (Mississippian: Weber and others, 1992; Mortensen and Thompson, 1990) - Light gray, light- to medium-gray weathering and iron-stained, fine to medium-grained, bimodal to moderately sorted, distinctive vitreous quartzite, with interbedded medium to dark gray slate, phyllite, and shaley rocks. Framework grains are well rounded to subrounded monocrystalline quartz, and minor chert clasts. Alaska Division of Geological & Geophysical Surveys Dl Devonian limestone fault slivers at Granite Creek [Famennian (late Late Devonian): this report] - Dark gray, light gray-weathering, lime mudstone. Uppermost strata of the largest fault sliver include abundant floating quartz grains up to 3 mm in diameter, which are increasingly abundant down-section. Alaska Division of Geological & Geophysical Surveys Dc Conglomerate (Late Devonian?: this report) - Dark gray to very dark gray, brown-weathering, clast-supported, chert-pebble to cobble conglomerate; matrix consists of siliciclastic and carbonate material, and clasts are sub-rounded pebble to cobble size. Alaska Division of Geological & Geophysical Surveys Pzlca Chert and cherty argillite (Ordovician) - Heterogeneous unit composed dominantly of light gray to gray, thinly laminated, recrystallized sericitic chert and siliceous argillite, commonly with phyllitic argillite partings; 'cherty argillite' typically has cherty or mylonitic aspect on weathered surfaces, but fine-grained elastic or recrystallized texture on fresh surfaces. Alaska Division of Geological & Geophysical Surveys Pzlv Volcanic unit (Ordovician) - Greenish-gray, chloritic and feldspathic rocks and greenstone. Protolith of volcanic rocks is volcaniclastic, tuffaceous, and flow rocks of basaltic to intermediate composition. Some rocks are diabasic and may be meta-intrusive rocks; the number of metavolcanic layers uncertain. Alaska Division of Geological & Geophysical Surveys Pzlo Orum limestone (Middle Ordovician to Neoproterozoic: informal name, Hopkins and Taber, unpublished manuscript) - Light to medium gray, tan to reddish brown-weathering, extensively recrystallized, typically thin- to medium-bedded lime mudstone. Unit is locally thick-bedded, and locally includes ooid grainstones and cryptalgal lamination. Alaska Division of Geological & Geophysical Surveys Ofc Fossil Creek volcanics (Late to Early Ordovician: Weber and others, 1992) - Heterogeneous assemblage of basalt, agglomerate, volcaniclastic conglomerate, lime wackestone, calcareous feldspathic sandstone, shale, siltstone, chert, slate, and phyllite. Alaska Division of Geological & Geophysical Surveys PzPad Dolostone and limestone - White to light gray, massive-bedded, locally laminated, siliceous dolostone and medium gray to dark gray lime mudstone, in approximately equal amounts. Dolostone is typically extensively silicified and characterized by box-work silica network. Alaska Division of Geological & Geophysical Surveys PzPag Greenstone - Dark greenish gray, massive to well-foliated, locally magnetic greenstone, amygdaloidal greenstone, and agglomeratic greenstone; basaltic to intermediate composition. Contains calcite amygdule fillings, locally abundant pyrite cubes, and slightly stretched volcanic and carbonate clasts up to cobble size. Alaska Division of Geological & Geophysical Surveys PzPac Cherty argillite and chert - Heterogeneous unit of dominantly black to dark gray chert and siliceous to carbonaceous argillite with well-developed phyllitic to subphyllitic slate-like cleavage, and containing one or more dark gray limestone layers or lenses. The geochemical signature of this unit is typical of the chert in the Amy Creek unit (Haug and others, 1997) of Weber and others (1988). Alaska Division of Geological & Geophysical Surveys PzPwg Siliciclastic rock - Medium gray, tan-weathering, thin-bedded, fine-grained argillaceous sandstone, siltstone, rare greenstone (?), and phyllitic argillite. Locally, these rocks include up to 30 percent calcite that likely represents recrystallized matrix. Black, non-calcareous, carbonaceous, phyllitic argillite interbeds and partings are common. Alaska Division of Geological & Geophysical Surveys Tg Hot Springs granite pluton (58 Ma) - Medium- to coarse-grained biotite granite and rare tourmaline-biotite granite. Outcrops as subdued, blocky rubble or a brown gruss. The dominant textural variety contains coarse-grained potassium feldspar (30 percent) in a matrix of medium-grained smoky quartz (30 percent), albitic plagioclase (30 percent), and slightly chloritized biotite (10 percent). Alaska Division of Geological & Geophysical Surveys Kmzd Monzodiorite - Black and white 'peppered,' medium-grained, subequigranular, alkalic plutonic rock lacking quartz and with more plagioclase than alkali feldspar. Mafic minerals (clinopyroxene > biotite > hornblende) commonly make up more than 50 percent of the rock. Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qag Old, high-level alluvial gravels - Irregular residual deposits of gold-bearing, pebble-cobble gravel with well rounded quartzite boulders up to 3 m diameter preserved on high interfluves in the Eureka Creek area; up to 4 m thick, but generally much thinner; locally extensively reworked by mining activity Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qld Delta deposits - Fan-shaped, heterogeneous mixture of well sorted silt, sand, and gravel; thick to thin bedded; shows cross-bedding and fining-upward cycles; surface smooth, except for numerous shallow, interconnected channels. Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys WATER body of water Alaska Division of Geological & Geophysical Surveys MAT Preliminary engineering-geologic map unit labels Alaska Division of Geological & Geophysical Surveys GS Fluvial and glaciofluvial gravel, sand, and silt. Chiefly (estimated >80 percent) clean sand and gravel. Grain size, sorting, and degree of stratification are variable. Permafrost may be present, especially in older deposits. Component geologic units include Qa, Qag, Qap, Qfp, and Qmt. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. GM Poorly to moderately well-sorted clay, silt, sand, gravel, and diamicton of colluvial and fluvial origins. Includes angular, unsorted talus debris and chaotically deformed colluvium derived from landslides. Component geologic units include Qac, Qaf, Qc, and Qca. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. SM Silt deposited primarily by wind and reworked by fluvial and colluvial processes. May be organic-rich. Commonly frozen and ice-rich, especially on north-facing slopes. Chiefly fine materials. Component geologic units include Qas, Qel, Qelp, Qer, Qld, and Qsf. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. OR Organic-rich silt and peat in bogs and thaw lake basins. Commonly frozen and ice-rich due to the excellent insulating properties of peat. Generally water-saturated. Component geologic units include Qs. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BC Medium-jointed, fine- to coarse-grained sedimentary carbonate rocks. Includes limestone, dolostone, and marble. Component geologic units include Dl, Pzlo, and PzPad. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BG Coarse-jointed, coarse-grained igneous lithologies. Chiefly granitic rocks. Component geologic units include Kgs, Kmo, Kmzd, Ksy, and Tg. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BM Medium-jointed, fine- to medium-grained quartzose sedimentary rocks. Includes quartzose sandstone and conglomerate, quartzite, chert, and hornfels. Component geologic units include Dc, KJwq, Kwcq, Mg, Pzlca, and TrPp. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BV Medium-jointed, fine-grained igneous rocks. Chiefly volcanic flow rock, dikes, and greenstone. Component geologic units include Kdm, Ofc, Pzlv, and PzPag. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BU Rocks of mixed lithology and very fine-grained sedimentary lithologies that are generally poorly suited for use as construction materials. Includes shale, siltstone, and argillite. Component geologic units include Kdm, Ofc, Pzlv, and PzPag. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. H20 body of water Alaska Division of Geological & Geophysical Surveys tana2comp_polygon.shp Object type is vector, there are 1,266 rows associated with this entity, and the entity values refer to comprehensive geologic polygons Alaska Division of Geological & Geophysical Surveys tana2comp_polygon BUNIT Interpretive geologic map unit labels Alaska Division of Geological & Geophysical Surveys FZONE Kaltag Fault Zone - Major dextral strike-slip fault zone connecting Tintina Fault Zone. The Kaltag fault zone is topographically subdued but cuts the Amy Creek dolomite unit and the Livengood Chert unit. Alaska Division of Geological & Geophysical Surveys Kwcq Wilber Creek unit quartzite (Albian: Weber and others, 1992) - Medium gray to light gray, highly quartzitic, hard, dense, argillaceous lithic quartzite. Quartzite interbeds occur locally as abundant laminae up to 20 cm thick in the Wilber Creek unit (map unit 'Kwcs') on the northern side of Manley Dome (where it is a mappable unit). Alaska Division of Geological & Geophysical Surveys Kdm Mafic dikes (95 Ma) - Very dark gray and greenish very dark gray, very fine grained hypabyssal dikes. Composition ranges from monzodiorite to monzonite, with little or no quartz, abundant clinopyroxene, and plagioclase subequal in abundance to alkali feldspar. Alaska Division of Geological & Geophysical Surveys Kgs Granite and quartz syenite - Buff to light gray, fine to coarse grained, sub-equigranular, holocrystalline rock. The rock exhibits slight hydrothermal alteration, with feldspar partly converted to fine-grained white mica. Quartz/(quartz + total feldspar) ratios vary from 15 to 35 percent, and the bulk of the feldspar appears to be K-feldspar. Alaska Division of Geological & Geophysical Surveys Ksy Syenite and quartz syenite - Black and white-'peppered,' coarse to medium grained, subequigranular to trachytoid, syenite, and quartz syenite. With the exception of euhedral, megacrystic, alkali feldspar, the minerals are typically subhedral and anhedral. Alaska Division of Geological & Geophysical Surveys Kmo Monzonite - Black and white 'peppered,' coarse to medium grained, locally foliated, subequigranular to trachytoid, porphyritic monzonite and quartz monzonite. Mineralogy is typically subhedral and anhedral, with the exception of euhedral megacrystic alkali feldspar. Alaska Division of Geological & Geophysical Surveys Pzum Ultramafic rocks (approximately 540 Ma) - Serpentinite, gabbro, and minor roddingite, which weather to a buff-colored massive rubble. Predominantly serpentinite, consisting of fine-grained, moderately foliated to unfoliated serpentine-talc with 2 to 5 percent fine- to medium-grained magnetite, 0 to 20 percent magnesite, 0 to 25 percent altered, medium-grained orthopyroxene, 0.1 to 0.5 percent fine- to medium-grained chromite, and 0 to 1 percent fine-grained chlorite. Alaska Division of Geological & Geophysical Surveys Kwcv Wilber Creek unit siliciclastic and volcaniclastic rocks (late Albian(?): Weber and others, 1992) - Very dark gray to dark greenish dark gray, volcanic clast-bearing, poorly sorted, sub-angular, medium- to coarse-grained, marine, argillaceous lithic sandstone, shale and siltstone. Estimates of the framework grain composition are 55 percent chert, 25 percent quartz, 15 percent plagioclase (which includes about 5 percent obvious volcanic clasts), and 5 percent sedimentary and metamorphic rock fragments, and minor white mica. Alaska Division of Geological & Geophysical Surveys Kwcs Wilber Creek unit sandstone, shale, siltstone, undivided (Albian: Weber and others, 1992) - Very dark gray to dark greenish gray, poorly sorted, marine, argillaceous lithic sandstone, shale, and siltstone containing white mica-bearing argillaceous sandstone as laminae and thin interbeds; rare conglomerate. Beds are typically thin, parallel, laterally continuous, sharp-based, and graded; from fine to medium grained at the base, grading up to silt at the top of beds. Alaska Division of Geological & Geophysical Surveys KJwq Wolverine quartzite unit (Early Cretaceous and Late Jurassic: Weber and others, 1992) - Very light gray to tan, white- to medium gray-weathering, moderately well-sorted, subrounded, fine- to medium-grained quartzite, and sublitharenite with interbedded shaley rocks. Estimates of sandstone clast composition indicate greater than 90 percent quartz (rare light-blue color), two to five percent chert, and locally trace amounts of feldspar and white mica. Alaska Division of Geological & Geophysical Surveys KJws Wolverine quartzite unit sandstone and shale, undivided (Early Cretaceous and Late Jurassic: Weber and others, 1992) - Medium gray to light gray, locally black, lichen-covered, quartz-rich sandstone and interbedded shale. Sandstone is silica-cemented, well-indurated quartzarenite but lacks the prominent outcrop pattern, continuity, and thickness of the quartzite unit (map unit 'KJwq'). Alaska Division of Geological & Geophysical Surveys TrPs ***Note: typographical error exists on the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1). Unit TrPa does not exist. Unit label should read TrPs.*** Argillite, sandstone, and shale (Triassic and Permian: Reifenstuhl and others, 1997a) - Dark gray to very dark gray, typically fine to very fine grained, argillaceous siliciclastic rocks,with common orange-brown weathering surfaces. Rocks have a better developed low-grade metamorphic fabric (phyllitic) compared to the Cretaceous to Jurassic age sandstone and shale lithologies above (map units 'KJwq', 'KJws'). Alaska Division of Geological & Geophysical Surveys TrPp Conglomerate (Triassic and Permian: Reifenstuhl and others, 1997a) - Very dark gray, orange-brown-weathering, matrix-supported, chert-pebble to cobble conglomerate. Matrix is dark gray argillite to very fine sand, and clasts are sub-rounded pebble to cobble size. Alaska Division of Geological & Geophysical Surveys Dc Conglomerate (Late Devonian?: this report) - Dark gray to very dark gray, brown-weathering, clast-supported, chert-pebble to cobble conglomerate; matrix consists of siliciclastic and carbonate material, and clasts are sub-rounded pebble to cobble size. Alaska Division of Geological & Geophysical Surveys Pzlca Chert and cherty argillite (Ordovician) - Heterogeneous unit composed dominantly of light gray to gray, thinly laminated, recrystallized sericitic chert and siliceous argillite, commonly with phyllitic argillite partings; 'cherty argillite' typically has cherty or mylonitic aspect on weathered surfaces, but fine-grained elastic or recrystallized texture on fresh surfaces. Alaska Division of Geological & Geophysical Surveys Pzlv Volcanic unit (Ordovician) - Greenish-gray, chloritic and feldspathic rocks and greenstone. Protolith of volcanic rocks is volcaniclastic, tuffaceous, and flow rocks of basaltic to intermediate composition. Some rocks are diabasic and may be meta-intrusive rocks; the number of metavolcanic layers uncertain. Alaska Division of Geological & Geophysical Surveys Pzlo Orum limestone (Middle Ordovician to Neoproterozoic: informal name, Hopkins and Taber, unpublished manuscript) - Light to medium gray, tan to reddish brown-weathering, extensively recrystallized, typically thin- to medium-bedded lime mudstone. Unit is locally thick-bedded, and locally includes ooid grainstones and cryptalgal lamination. Alaska Division of Geological & Geophysical Surveys PzPad Dolostone and limestone - White to light gray, massive-bedded, locally laminated, siliceous dolostone and medium gray to dark gray lime mudstone, in approximately equal amounts. Dolostone is typically extensively silicified and characterized by box-work silica network. Alaska Division of Geological & Geophysical Surveys PzPac Cherty-argillite and chert - Heterogeneous unit of dominantly black to dark gray chert and siliceous to carbonaceous argillite with well-developed phyllitic to subphyllitic slate-like cleavage, and containing one or more dark gray limestone layers or lenses. The geochemical signature of this unit is typical of the chert in the Amy Creek unit (Haug and others, 1997) of Weber and others (1988). Alaska Division of Geological & Geophysical Surveys Tg Hot Springs granite pluton (58 Ma) - Medium- to coarse-grained biotite granite and rare tourmaline-biotite granite. Outcrops as subdued, blocky rubble or a brown gruss. The dominant textural variety contains coarse-grained potassium feldspar (30 percent) in a matrix of medium-grained smoky quartz (30 percent), albitic plagioclase (30 percent), and slightly chloritized biotite (10 percent). Alaska Division of Geological & Geophysical Surveys Kmzd Monzodiorite - Black and white 'peppered,' medium grained, subequigranular, alkalic plutonic rock lacking quartz and with more plagioclase than alkali feldspar. Mafic minerals (clinopyroxene > biotite > hornblende) commonly make up more than 50 percent of the rock. Alaska Division of Geological & Geophysical Surveys JRc Carbonatite (approximately 200 Ma) - Medium to coarse grained, dolomite-calcite-magnetite-apatite-rich rock, which weathers to a deep red gossan and is characterized by an intense magnetic high. Occurs as two steeply dipping sills (?) up to 30 m thick, which may be a single sill or dike that is repeated by isoclinal folding. Alaska Division of Geological & Geophysical Surveys SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - Bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - Bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones Alaska Division of Geological & Geophysical Surveys UNIT Generic geologic map unit labels Alaska Division of Geological & Geophysical Surveys Kwcs Wilber Creek unit sandstone, shale, siltstone, undivided (Albian: Weber and others, 1992) - Very dark gray to dark greenish gray, poorly sorted, marine, argillaceous lithic sandstone, shale, and siltstone containing white mica-bearing argillaceous sandstone as laminae and thin interbeds; rare conglomerate. Beds are typically thin, parallel, laterally continuous, sharp-based, and graded; from fine to medium grained at the base, grading up to silt at the top of beds. Alaska Division of Geological & Geophysical Surveys KJwq Wolverine quartzite unit (Early Cretaceous and Late Jurassic: Weber and others, 1992) - Very light gray to tan, white- to medium gray-weathering, moderately well-sorted, subrounded, fine- to medium-grained quartzite, and sublitharenite with interbedded shaley rocks. Estimates of sandstone clast composition indicate greater than 90 percent quartz (rare light-blue color), two to five percent chert, and locally trace amounts of feldspar and white mica. Alaska Division of Geological & Geophysical Surveys KJws Wolverine quartzite unit sandstone and shale, undivided (Early Cretaceous and Late Jurassic: Weber and others, 1992) - Medium gray to light gray, locally black, lichen-covered, quartz-rich sandstone and interbedded shale. Sandstone is silica-cemented, well-indurated quartzarenite but lacks the prominent outcrop pattern, continuity, and thickness of the quartzite unit (map unit 'KJwq'). Alaska Division of Geological & Geophysical Surveys TrPs ***Note: typographical error exists on the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1). Unit TrPa does not exist. Unit label should read TrPs.*** Argillite, sandstone and shale (Triassic and Permian: Reifenstuhl and others, 1997a) - Dark gray to very dark gray, typically fine to very fine grained, argillaceous siliciclastic rocks,with common orange-brown weathering surfaces. Rocks have a better developed low-grade metamorphic fabric (phyllitic) compared to the Cretaceous to Jurassic age sandstone and shale lithologies above (map units 'KJwq', 'KJws'). Alaska Division of Geological & Geophysical Surveys TrPp Conglomerate (Triassic and Permian: Reifenstuhl and others, 1997a) - Very dark gray, orange-brown weathering, matrix-supported, chert-pebble to cobble conglomerate. Matrix is dark gray argillite to very fine sand, and clasts are sub-rounded pebble to cobble size. Alaska Division of Geological & Geophysical Surveys Dc Conglomerate (Late Devonian?: this report) - Dark gray to very dark gray, brown-weathering, clast-supported, chert-pebble to cobble conglomerate; matrix consists of siliciclastic and carbonate material, and clasts are sub-rounded pebble to cobble size. Alaska Division of Geological & Geophysical Surveys Pzlca Chert and cherty argillite (Ordovician) - Heterogeneous unit composed dominantly of light gray to gray, thinly laminated, recrystallized sericitic chert and siliceous argillite, commonly with phyllitic argillite partings; 'cherty argillite' typically has cherty or mylonitic aspect on weathered surfaces, but fine-grained elastic or recrystallized texture on fresh surfaces. Alaska Division of Geological & Geophysical Surveys Pzlv Volcanic unit (Ordovician) - Greenish-gray, chloritic and feldspathic rocks and greenstone. Protolith of volcanic rocks is volcaniclastic, tuffaceous, and flow rocks of basaltic to intermediate composition. Some rocks are diabasic and may be meta-intrusive rocks; the number of metavolcanic layers uncertain. Alaska Division of Geological & Geophysical Surveys Pzlo Orum limestone (Middle Ordovician to Neoproterozoic: informal name, Hopkins and Taber, unpublished manuscript) - Light to medium gray, tan to reddish brown-weathering, extensively recrystallized, typically thin- to medium-bedded lime mudstone. Unit is locally thick-bedded, and locally includes ooid grainstones and cryptalgal lamination. Alaska Division of Geological & Geophysical Surveys PzPad Dolostone and limestone - White to light gray, massive-bedded, locally laminated, siliceous dolostone and medium gray to dark gray lime mudstone, in approximately equal amounts. Dolostone is typically extensively silicified and characterized by box-work silica network. Alaska Division of Geological & Geophysical Surveys PzPac Cherty-argillite and chert - Heterogeneous unit of dominantly black to dark gray chert and siliceous to carbonaceous argillite with well-developed phyllitic to subphyllitic slate-like cleavage, and containing one or more dark gray limestone layers or lenses. The geochemical signature of this unit is typical of the chert in the Amy Creek unit (Haug and others, 1997) of Weber and others (1988). Alaska Division of Geological & Geophysical Surveys Tg Hot Springs granite pluton (58 Ma) - Medium- to coarse-grained biotite granite and rare tourmaline-biotite granite. Outcrops as subdued, blocky rubble or a brown gruss. The dominant textural variety contains coarse-grained potassium feldspar (30 percent) in a matrix of medium-grained smoky quartz (30 percent), albitic plagioclase (30 percent), and slightly chloritized biotite (10 percent). Alaska Division of Geological & Geophysical Surveys Kmzd Monzodiorite- Black and white 'peppered,' medium grained, subequigranular, alkalic plutonic rock lacking quartz and with more plagioclase than alkali feldspar. Mafic minerals (clinopyroxene > biotite > hornblende) commonly make up more than 50 percent of the rock. Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys Kwcq Wilber Creek unit quartzite (Albian: Weber and others, 1992) - Medium to light gray, highly quartzitic, hard, dense, argillaceous lithic quartzite. Quartzite interbeds occur locally as abundant laminae up to 20 cm thick in the Wilber Creek unit (map unit 'Kwcs') on the northern side of Manley Dome (where it is a mappable unit). Alaska Division of Geological & Geophysical Surveys Kdm Mafic dikes (95 Ma) - Very dark gray and greenish very dark gray, very fine grained hypabyssal dikes. Composition ranges from monzodiorite to monzonite, with little or no quartz, abundant clinopyroxene, and plagioclase subequal in abundance to alkali feldspar. Alaska Division of Geological & Geophysical Surveys Kgs Granite and quartz syenite - Buff to light gray, fine to coarse grained, sub-equigranular, holocrystalline rock. The rock exhibits slight hydrothermal alteration, with feldspar partly converted to fine-grained white mica. Quartz/(quartz + total feldspar) ratios vary from 15 to 35 percent, and the bulk of the feldspar appears to be K-feldspar. Alaska Division of Geological & Geophysical Surveys Ksy Syenite and quartz syenite - Black and white-'peppered,' coarse to medium grained, subequigranular to trachytoid, syenite and quartz syenite. With the exception of euhedral, megacrystic, alkali feldspar, the minerals are typically subhedral and anhedral. Alaska Division of Geological & Geophysical Surveys Kmo Monzonite - Black and white 'peppered,' coarse to medium grained, locally foliated, subequigranular to trachytoid, porphyritic monzonite and quartz monzonite. Mineralogy is typically subhedral and anhedral, with the exception of euhedral megacrystic alkali feldspar. Alaska Division of Geological & Geophysical Surveys Pzum Ultramafic rocks (approximately 540 Ma) - Serpentinite, gabbro, and minor roddingite, which weather to a buff-colored massive rubble. Predominantly serpentinite, consisting of fine-grained, moderately foliated to unfoliated serpentine-talc with 2 to 5 percent fine- to medium-grained magnetite, 0 to 20 percent magnesite, 0 to 25 percent altered, medium-grained orthopyroxene, 0.1 to 0.5 percent fine- to medium-grained chromite, and 0 to 1 percent fine-grained chlorite. Alaska Division of Geological & Geophysical Surveys JRc Carbonatite (approximately 200 Ma) - Medium to coarse grained, dolomite-calcite-magnetite-apatite-rich rock, which weathers to a deep red gossan and is characterized by an intense magnetic high. Occurs as two steeply-dipping sills (?) up to 30 m thick, which may be a single sill or dike that is repeated by isoclinal folding. Alaska Division of Geological & Geophysical Surveys MAT Preliminary engineering-geologic map unit labels Alaska Division of Geological & Geophysical Surveys GS Fluvial and glaciofluvial gravel, sand, and silt. Chiefly (estimated >80 percent) clean sand and gravel. Grain size, sorting and degree of stratification are variable. Permafrost may be present, especially in older deposits. Component geologic units include Qa, Qag, Qap, Qfp, and Qmt. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. GM Poorly- to moderately well-sorted clay, silt, sand, gravel, and diamicton of colluvial and fluvial origins. Includes angular, unsorted talus debris and chaotically deformed colluvium derived from landslides. Component geologic units include Qac, Qaf, Qc, and Qca. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. SM Silt deposited primarily by wind and reworked by fluvial and colluvial processes. May be organic-rich. Commonly frozen and ice-rich, especially on north-facing slopes. Chiefly fine materials. Component geologic units include Qas, Qel, Qelp, Qer, Qld, and Qsf. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. OR Organic-rich silt and peat in bogs and thaw lake basins. Commonly frozen and ice-rich due to the excellent insulating properties of peat. Generally water-saturated. Component geologic units include Qs. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BC Medium-jointed, fine- to coarse-grained sedimentary carbonate rocks. Includes limestone, dolostone, and marble. Component geologic units include Dl, Pzlo, and PzPad. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BG Coarse-jointed, coarse-grained igneous lithologies. Chiefly granitic rocks. Component geologic units include Kgs, Kmo, Kmzd, Ksy, and Tg. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BM Medium-jointed, fine- to medium-grained quartzose sedimentary rocks. Includes quartzose sandstone and conglomerate, quartzite, chert, and hornfels. Component geologic units include Dc, KJwq, Kwcq, Mg, Pzlca, and TrPp. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BO Rocks of lithologies not listed in other materials classes, but which may be suited for use as construction materials or for other specialized purposes. Includes carbonatite and ultramafic rocks. Component geologic units include JRc and Pzum. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BV Medium-jointed, fine-grained igneous rocks. Chiefly volcanic flow rock, dikes, and greenstone. Component geologic units include Kdm, Ofc, Pzlv, and PzPag. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. BU Rocks of mixed lithology and very fine-grained sedimentary lithologies that are generally poorly suited for use as construction materials. Includes shale, siltstone, and argillite. Component geologic units include Kdm, Ofc, Pzlv, and PzPag. Source of geologic units: Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A. Alaska Division of Geological & Geophysical Surveys. See Pinney, D.S., 1998, Derivative engineering geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37D for more information. hflsa1_comp_polygon.shp Object type is vector, there are 497 rows associated with this entity, and the entity values refer to comprehensive geologic polygons Alaska Division of Geological & Geophysical Surveys hflsa1_comp_polygon SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qag Old, high-level alluvial gravels - Irregular residual deposits of gold-bearing, pebble-cobble gravel with well rounded quartzite boulders up to 3 m diameter preserved on high interfluves in the Eureka Creek area; up to 4 m thick, but generally much thinner; locally extensively reworked by mining activity Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qld Delta deposits - Fan-shaped, heterogeneous mixture of well sorted silt, sand, and gravel; thick to thin bedded; shows cross-bedding and fining-upward cycles; surface smooth, except for numerous shallow, interconnected channels. Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys nm Not mapped, body of water, region is irrelevant and not meaningful for the particular data layer. : the polygon having the software-defined attribute/column FID whose value is 451 represents Baker Lake. The annotation "Baker Lake", as seen on the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1), is not preserved in the geologic polygon table.*** Alaska Division of Geological & Geophysical Surveys UNIT Generic geologic map unit labels Alaska Division of Geological & Geophysical Surveys HFELS Hornfels near intrusions are very dark gray to black, very fine to fine grained, hard, dense rocks with common disoriented crystals or rosettes of muscovite, biotite, and locally andalusite. Typically formed by contact metamorphism. Alaska Division of Geological & Geophysical Surveys hflsa2_comp_polygon.shp Object type is vector, there are 595 rows associated with this entity, and the entity values refer to comprehensive geologic polygons Alaska Division of Geological & Geophysical Surveys hflsa2_comp_polygon SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys UNIT Generic geologic map unit labels Alaska Division of Geological & Geophysical Surveys HFELS Hornfels near intrusions are very dark gray to black, very fine to fine grained, hard, dense rocks with common disoriented crystals or rosettes of muscovite, biotite, and locally andalusite. Typically formed by contact metamorphism. Alaska Division of Geological & Geophysical Surveys NM Not mapped, region is irrelevant and not meaningful for the particular data layer Alaska Division of Geological & Geophysical Surveys tana1bedcon_arc.shp Object type is vector, there are 844 rows associated with this entity, and the entity values refer to comprehensive geologic unit contacts Alaska Division of Geological & Geophysical Surveys tana1bedcon_arc CODE Line symbols for contacts, defined as boundaries between geologic formations or other rock units Alaska Division of Geological & Geophysical Surveys 0 Hidden line, defines the polygon boundary, but is not displayed on the map for aesthetic purposes Alaska Division of Geological & Geophysical Surveys 5 Contact Alaska Division of Geological & Geophysical Surveys 9 Contact, concealed, generally buried beneath a mapped geologic unit, water, or ice Alaska Division of Geological & Geophysical Surveys SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qag Old, high-level alluvial gravels - Irregular residual deposits of gold-bearing, pebble-cobble gravel with well rounded quartzite boulders up to 3 m diameter preserved on high interfluves in the Eureka Creek area; up to 4 m thick, but generally much thinner; locally extensively reworked by mining activity Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys tana2bedcon_arc.shp Object type is vector, there are 1,244 rows associated with this entity, and the entity values refer to comprehensive geologic unit contacts Alaska Division of Geological & Geophysical Surveys tana2bedcon_arc CODE Line symbols for contacts, defined as boundaries between geologic formations or other rock units Alaska Division of Geological & Geophysical Surveys 0 Hidden line, defines the polygon boundary, but is not displayed on the map for aesthetic purposes Alaska Division of Geological & Geophysical Surveys 5 Contact Alaska Division of Geological & Geophysical Surveys 9 Contact, concealed, generally buried beneath a mapped geologic unit, water, or ice Alaska Division of Geological & Geophysical Surveys SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock- bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock- bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys tana1strline_arc.shp Object type is vector, there are 976 rows associated with this entity, and the entity values refer to types of faults Alaska Division of Geological & Geophysical Surveys tana1strline_arc CODE Line symbols for types of faults Alaska Division of Geological & Geophysical Surveys 11 Fault Alaska Division of Geological & Geophysical Surveys 12 Fault approximately located Alaska Division of Geological & Geophysical Surveys 15 Fault, concealed, generally under overlying mapped deposits, ice, or water. ***Note: arcs having the software-defined attribute/column FID whose values are 630, 633, 635, 636, 643, 644, 670, 672, 682, 686, 689, 690, 696, 698, 701, 702, 704-706, and 708 represent the Stevens Creek Fault (continued in the Entity_Attribute_Layer "tana2strline" listed below). The annotation "Stevens Creek Fault", as seen on the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1), is not preserved in the structure table.*** Alaska Division of Geological & Geophysical Surveys 17 Thrust fault, sawteeth on upper plate, user will need to see the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1) for interpretation of relative plate motion Alaska Division of Geological & Geophysical Surveys 18 Thrust fault, approximately located, user will need to see the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1) for interpretation of relative plate motion Alaska Division of Geological & Geophysical Surveys 20 Thrust fault, probable, user will need to see the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1) for interpretation of relative plate motion Alaska Division of Geological & Geophysical Surveys 22 Thrust fault, concealed, user will need to see the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1) for interpretation of relative plate motion Alaska Division of Geological & Geophysical Surveys SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock- bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams-Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qag Old, high-level alluvial gravels - Irregular residual deposits of gold-bearing, pebble-cobble gravel with well rounded quartzite boulders up to 3 m diameter preserved on high interfluves in the Eureka Creek area; up to 4 m thick, but generally much thinner; locally extensively reworked by mining activity Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys tana2strline_arc.shp Object type is vector, there are 1,103 rows associated with this entity, and the entity values refer to types of faults Alaska Division of Geological & Geophysical Surveys tana2strline_arc CODE Line symbols for types of faults Alaska Division of Geological & Geophysical Surveys 11 Fault Alaska Division of Geological & Geophysical Surveys 12 Fault approximately located Alaska Division of Geological & Geophysical Surveys 15 Fault, concealed, generally under overlying mapped deposits, ice, or water. ***Note: arcs having the software-defined attribute/column FID whose values are 39, 41, 58, 59, 73, 85, 92, 96, 118, 121, 123, 143, 145, 149, 159, 166, 168, 178, 179, 183, 208, 209, 211, 217, 218, 224, 232, 235, 239, 249, 253, 254, 216, 267, 291, 303, 306, 315, 351, 364, 439, 452, 488, 493, 506, 515, 529, 531, 546, 548, 550, 553, 556, 568, and 580 represent the Stevens Creek Fault (continued from the Entity_Attribute_Layer "tana1strline" listed above). Arcs having the software-defined attribute/column FID whose values are 1-7, 11, 13, 15, 19, 20, 24, 27, 28, 36, 54, 56, 60, 65, 67, 69, 72, 74, and 79 represent the Kaltag Fault Zone. The annotations "Stevens Creek Fault" and "Kaltag Fault Zone", as seen on the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1), are not preserved in the structure table.*** Alaska Division of Geological & Geophysical Surveys 17 Thrust fault, sawteeth on upper plate, user will need to see the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1) for interpretation of relative plate motion Alaska Division of Geological & Geophysical Surveys 18 Thrust fault, approximately located, user will need to see the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1) for interpretation of relative plate motion Alaska Division of Geological & Geophysical Surveys 22 Thrust fault, concealed, user will need to see the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1) for interpretation of relative plate motion Alaska Division of Geological & Geophysical Surveys SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys tana1srf_polygon.shp Object type is vector, there are 490 rows associated with this entity, and the entity values refer to comprehensive geologic polygons Alaska Division of Geological & Geophysical Surveys tana1srf_polygon SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qag Old, high-level alluvial gravels - Irregular residual deposits of gold-bearing, pebble-cobble gravel with well rounded quartzite boulders up to 3 m diameter preserved on high interfluves in the Eureka Creek area; up to 4 m thick, but generally much thinner; locally extensively reworked by mining activity Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qld Delta deposits - Fan-shaped, heterogeneous mixture of well sorted silt, sand, and gravel; thick to thin bedded; shows cross-bedding and fining-upward cycles; surface smooth, except for numerous shallow, interconnected channels. Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys WATER Body of water. ***Note: the polygon having the software-defined attribute/column FID whose value is 441 represents Baker Lake. The annotation "Baker Lake", as seen on the Preliminary Geologic Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37A-SH1), is not preserved in the geologic polygon table.*** Alaska Division of Geological & Geophysical Surveys tana2srf_polygon.shp Object type is vector, there are 438 rows associated with this entity, and the entity values refer to comprehensive geologic polygons Alaska Division of Geological & Geophysical Surveys tana2srf_polygon SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings - Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys tana1fld_point.shp Object type is point, there are 9 rows associated with this entity, and the entity values refer to types of anticlines or synclines Alaska Division of Geological & Geophysical Surveys tana1fld_point CODE Point symbols for types of folds, anticlines, or synclines Alaska Division of Geological & Geophysical Surveys 22 Anticline Alaska Division of Geological & Geophysical Surveys 23 Syncline Alaska Division of Geological & Geophysical Surveys 27 Overturned anticline, showing direction of dip of limbs Alaska Division of Geological & Geophysical Surveys tana2fld_point.shp Object type is point, there are 31 rows associated with this entity, and the entity values refer to types of anticlines or synclines Alaska Division of Geological & Geophysical Surveys tana2fld_point CODE Point symbols for types of folds, anticlines, or synclines Alaska Division of Geological & Geophysical Surveys 22 Anticline Alaska Division of Geological & Geophysical Surveys 23 Syncline Alaska Division of Geological & Geophysical Surveys 26 Overturned syncline, showing direction of dip of limbs Alaska Division of Geological & Geophysical Surveys tana1fldline_arc.shp Object type is vector, there are 211 rows associated with this entity, and the entity values refer to types of folds, anticlines, synclines, or lines depicting a cross-section Alaska Division of Geological & Geophysical Surveys tana1fldline_arc CODE Line symbols for types of folds, anticlines, synclines, or lines depicting a cross-section Alaska Division of Geological & Geophysical Surveys 4 Generic line depicting a type of fold, anticline, syncline, or cross-section location Alaska Division of Geological & Geophysical Surveys 34 Fold axis. This line, in combination with the proper point symbol, indicates the location of an anticline or syncline (see Entity_Type_Label "tana1fld.pat" above). Alaska Division of Geological & Geophysical Surveys 36 Inferred anticline or syncline. This line, in combination with the proper point symbol, indicates the location of an anticline or syncline (see Entity_Type_Label "tana1fld.pat" above). Alaska Division of Geological & Geophysical Surveys 38 Anticline or syncline, concealed. This line, in combination with the proper point symbol, indicates the location of an anticline or syncline (see Entity_Type_Label "tana1fld.pat" above). Alaska Division of Geological & Geophysical Surveys XSECT Indicates whether or not the line represents a cross-section. Alaska Division of Geological & Geophysical Surveys "Yes" - The line represents a cross-section. "No" - The line does not represent a cross-section. SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qag Old, high-level alluvial gravels - Irregular residual deposits of gold-bearing, pebble-cobble gravel with well rounded quartzite boulders up to 3 m diameter preserved on high interfluves in the Eureka Creek area; up to 4 m thick, but generally much thinner; locally extensively reworked by mining activity Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt--Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits-Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys Qmt Mine tailings-Water-washed pebble-cobble gravel with trace to some sand reworked by placer mining operations; typically well sorted; surface irregular or forming symmetrical ridges and cones. Alaska Division of Geological & Geophysical Surveys tana2fldline_arc.shp Object type is vector, there are 198 rows associated with this entity, and the entity values refer to types of folds, anticlines, synclines, or lines depicting a cross-section Alaska Division of Geological & Geophysical Surveys tana2fldline_arc CODE Line symbols for types of folds, anticlines, synclines, or lines depicting a cross-section Alaska Division of Geological & Geophysical Surveys 4 Generic line depicting a type of fold, anticline, syncline, or cross-section location Alaska Division of Geological & Geophysical Surveys 34 Fold axis. This line, in combination with the proper point symbol, indicates the location of an anticline or syncline (see Entity_Type_Label "tana2fld.pat" above). Alaska Division of Geological & Geophysical Surveys 36 Inferred anticline or syncline. This line, in combination with the proper point symbol, indicates the location of an anticline or syncline (see Entity_Type_Label "tana2fld.pat" above). Alaska Division of Geological & Geophysical Surveys 38 Anticline or syncline, concealed. This line, in combination with the proper point symbol, indicates the location of an anticline or syncline (see Entity_Type_Label "tana2fld.pat" above). Alaska Division of Geological & Geophysical Surveys XSECT Indicates whether or not the line represents a cross-section. Alaska Division of Geological & Geophysical Surveys "Yes" - The line represents a cross-section. "No" - The line does not represent a cross-section. SUNIT Surficial geologic map unit labels Alaska Division of Geological & Geophysical Surveys b Exposed bedrock - bedrock with essentially no cover Alaska Division of Geological & Geophysical Surveys bc Thinly covered bedrock - bedrock covered by thin (generally less than 1 m thick) veneer of surficial debris Alaska Division of Geological & Geophysical Surveys Qaf Alluvial fan deposits - Fan-shaped, heterogeneous mixtures of gravel with some sand and silt and few to numerous, subangular to rounded boulders, especially in proximal areas; clasts locally derived; may include debris-flow deposits; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels; locally covered by reworked silt. Alaska Division of Geological & Geophysical Surveys Qa Alluvium in modern stream channels - Elongated deposits of stratified gravel and sand with few to numerous boulders underlying active streams, flood plains, and associated low terraces; well sorted and medium to thick bedded, locally cross-bedded; shows fining-upward cycles. Alaska Division of Geological & Geophysical Surveys Qap Alluvial plain deposits - Irregular blankets and low-angle fans of stratified gravel and sand with silt interbeds and few to numerous boulders underlying much of Baker Creek flats; well sorted and medium to thick bedded, locally cross-bedded; surface flat to gently sloping with numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qas Silty alluvium in modern stream channels - Irregular, elongated deposits of stratified silt beneath modern channels and flood plains of streams draining loess-mantled slopes; may include fine-grained debris flow deposits, especially in the upper reaches; moderately to well sorted and medium to thin bedded, locally cross-bedded. Alaska Division of Geological & Geophysical Surveys Qfp Floodplain alluvium bordering modern streams - Elongated deposits of stratified pebble-cobble gravel and medium sand with few to numerous boulders forming modern flood plains and associated low (~3 m) terraces; typically mantled by thin layer of silty over-bank deposits Alaska Division of Geological & Geophysical Surveys Qsf Silt fan deposits - Fan-shaped deposits of dark brown to gray silt with some sand and angular to subrounded pebbles in proximal areas; may include fine-grained debris flow deposits, especially in the upper reaches; thick to thin bedded; surface smooth, except for numerous shallow, interconnected channels Alaska Division of Geological & Geophysical Surveys Qac Undifferentiated alluvial and colluvial valley-fill deposits - Fan-shaped and elongated heterogeneous mixtures of subangular rock fragments and gravel with some silt and sand deposited in upper stream courses primarily by brief, intense summer stream flow, debris flows, and gelifluction; surface smooth, except for local low scarps and shallow, steep-sided channels. Alaska Division of Geological & Geophysical Surveys Qc Undifferentiated colluvium - Irregular, heterogeneous blankets, aprons, and fans of angular to subrounded rock fragments, gravel, sand, and silt that are left on slopes, slope bases, or high-level surfaces by residual weathering and complex mass-movement processes, including rolling, sliding, flowing, gelifluction, and frost creep Alaska Division of Geological & Geophysical Surveys Qca Colluvial apron and fan deposits - Apron- and fan-shaped, heterogeneous mixtures of angular rock fragments with trace to some gravel, sand, and silt deposited at the bases of steep walls of modern stream valleys; may include or be capped by a considerable amount of redeposited eolian silt; locally washed by meltwater and slope runoff; surface steep to gently sloping. Alaska Division of Geological & Geophysical Surveys Qel Loess - Homogeneous blankets of well-sorted, mottled, light grayish-brown silt deposited by eolian processes; generally structureless, but with broadly horizontal bedding and some laminations, wavy bedding, and small-scale cross-bedding; contains scattered small charcoal fragments and root casts; local cryoturbation structures Alaska Division of Geological & Geophysical Surveys Qelp Pitted loess - Homogeneous blankets of mottled, light grayish-brown silt and organic silt deposited by eolian processes and subsequently modified by melting of ice-rich permafrost; generally massive to locally bedded Alaska Division of Geological & Geophysical Surveys Qer Reworked upland silt - Heterogeneous blankets of silt and organic silt originally laid down by eolian processes and subsequent minor to extensive reworking by fluvial and colluvial processes; includes silt-rich debris-flow deposits; may contain angular clasts of local origin; massive to thinly bedded, with some wavy bedding and cross-bedding; commonly perennially frozen and ice rich Alaska Division of Geological & Geophysical Surveys Qs Swamp deposits - Semicircular to irregular deposits of silt and peat in poorly-drained areas; saturated and locally frozen below a depth of about 1 m, locally ice rich; surface flat and smooth, may have standing water. Alaska Division of Geological & Geophysical Surveys tana1bur_arc.shp Object type is vector, there are 5 rows associated with this entity, and the entity values refer to various types of geophysical features as described in the accompanying report Alaska Division of Geological & Geophysical Surveys tana1bur_arc CODE Line symbols for various types of geophysical features Alaska Division of Geological & Geophysical Surveys 0 Hidden line, defines the polygon boundary, but is not displayed on the map for aesthetic purposes Alaska Division of Geological & Geophysical Surveys 64 Buried anomaly, boundary of airborne geophysical signature: high magnetics and low resistivity Alaska Division of Geological & Geophysical Surveys tana2bur_arc.shp Object type is vector, there are 5 rows associated with this entity, and the entity values refer to various types of geophysical features as described in the accompanying report Alaska Division of Geological & Geophysical Surveys tana2bur_arc CODE Line symbols for various types of geophysical features Alaska Division of Geological & Geophysical Surveys 0 Hidden line, defines the polygon boundary, but is not displayed on the map for aesthetic purposes Alaska Division of Geological & Geophysical Surveys 64 Buried anomaly, boundary of airborne geophysical signature: high magnetics and low resistivity Alaska Division of Geological & Geophysical Surveys 65 Buried anomaly, boundary of airborne geophysical signature: low magnetics and high resistivity Alaska Division of Geological & Geophysical Surveys tana12_att_point.shp Object type is point, there are 444 rows associated with this entity, and the entity values refer to the strike, dip, and plunge of bedding planes, foliation, and various lineaments Alaska Division of Geological & Geophysical Surveys tana12_att_point INDEX Generic example of unique sample identifier or location of a geologic measurement: YrAAA999X: Yr=2 digit year of sample collection, AAA=geologist's initials (one to three characters), 999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials are: BT - B. Taber, DS - D. Stevens, JD - J. Dover, KC - K. Clautice, RB - R. Blodgett, RN - R. Newberry, RR - R. Reifenstuhl, SH - S. Haug, SL - S. Liss. Alaska Division of Geological & Geophysical Surveys Unique sample number designated by the author(s). SYMBOL Point symbols for types of bedding and foliation orientation data Alaska Division of Geological & Geophysical Surveys 1 Strike and dip direction of beds Alaska Division of Geological & Geophysical Surveys 3 Strike and dip direction of beds, top of beds known from sedimentary features Alaska Division of Geological & Geophysical Surveys 4 Strike and dip direction of overturned beds Alaska Division of Geological & Geophysical Surveys 5 Strike of vertical beds, stratigraphic tops to north Alaska Division of Geological & Geophysical Surveys 7 Bearing of plunge of lineation Alaska Division of Geological & Geophysical Surveys 9 Strike and dip direction of foliation Alaska Division of Geological & Geophysical Surveys 12 Strike and dip direction of cleavage Alaska Division of Geological & Geophysical Surveys 13 Strike of vertical cleavage Alaska Division of Geological & Geophysical Surveys 19 Strike and dip direction of joints Alaska Division of Geological & Geophysical Surveys 20 Strike of vertical joints Alaska Division of Geological & Geophysical Surveys ANGLE Strike of plane using "Right-hand rule," where north is 0 and degrees increase clockwise to 360, always 90 degrees counter-clockwise from dip direction Alaska Division of Geological & Geophysical Surveys 3 360 degrees DIPANGLE Degrees that a plane is inclined relative to horizontal, horizontal being 0 degrees, vertical being 90 degrees; always 90 degrees clockwise from strike Alaska Division of Geological & Geophysical Surveys 10 90 degrees SHOW Indicates whether or not the point is printed on the published paper map Alaska Division of Geological & Geophysical Surveys "Yes" - The point is printed or shown on the Preliminary Interpretive Geologic Bedrock Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37B-SH1). "No" - The point is not printed or shown on the Preliminary Interpretive Geologic Bedrock Map of the Tanana A-1 and A-2 Quadrangles, Central Alaska (Publication PDF98-37B-SH1). A value of "No" may indicate that a duplicate value was measured nearby or the point was simply omitted at the discretion of the author(s). State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Natural Resource Technician mailing and physical

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