Surficial geologic map of the Circle mining district, Alaska

Reger, R.D.Pinney, D.S.1995Surficial geologic map of the Circle mining district, AlaskageodatabaseReport of InvestigationRI 95-2CFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2516Surficial geologic map of the Circle mining district, Alaska, Report of Investigation 95-2C, presents results from a geologic investigation of surficial deposits in parts of the Circle B-1, B-2, B-3, B-4, C-2, C-3, and C-4 quadrangles. The surficial deposits of the Circle mining district have long been sources of placer gold and even alluvial diamonds. Throughout most of the map area, the bedrock surface is blanketed by periglacial slope deposits consisting of silty rubble with angular and subangular clasts of local bedrock. This unconsolidated unsorted material was produced by intense frost shattering of bedrock and was spread downslope by mass movement processes. These processes are still active in the area today. In valley bottoms, terrace and floodplain alluvium consist of coarse, angular to subangular gravels. In upland valleys, the locally auriferous are commonly mixed with slope debris. Radiocarbon dating of organic sediments ranges in age from mid-Wisconsonian to Holocene. Although frost is discontinuous, sentiments in the valley are generally frozen and locally contain bones of large extinct vertebrae. Although landforms have been extensively modified by erosion, frost action, and mass movement, recognizable glacially modified valleys, silty gravel, and till provide evidence of at least one former glaciation. Glaciation of North Harrison Creek probably had a significant effect on the distribution of nuggets there. The complete report, geodatabase, and ESRI fonts and style files are available from the DGGS website: http://doi.org/10.14509/2516.The investigation of gold and other mineral occurrences in conjunction with comprehensive geologic mapping and recently acquired geophysical data provide a scientific basis for continued mineral exploration throughout the Circle mining district project area.This geodatabase is organized according to the AK GeMS mapping schema Hendricks, M.D., Ekberg, P.G., Athey, J.E., Wyatt, W.C., Willingham, A.L., and Naibert, T.J., 2021, AK GeMS data dictionary: A description of the Alaska geologic mapping schema: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 170, 10 p. https://doi.org/10.14509/30669. The distribution package includes ESRI fonts and style files, along with usage instructions. Further documentation of the symbology is provided by Ekberg, P.G., Hendricks, M.D., and Athey, J.E., 2021, AK GeMS symbology: A description of the AK GeMS style file: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 169, 7 p. https://doi.org/10.14509/3058419912024ground conditionCompleteNone planned-145.721623-144.48127765.58583265.368219ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAlluvial DepositsAlluvial FanAlluviumColluvial DepositsColluviumEolianFloodplainFloodplain AlluviumFluvial DepositsFossilsGelifluctionGeochronologyGeologic MapGeologyGeomorphologyGlacialGlacial DepositsGravelMastodonNon-MetalsPeatPermafrostPermafrost and PeriglacialPhotogeologic LineamentsSurficialSurficial Geologic MapSurficial GeologyTailingsTerrace AlluviumUnconsolidated DepositsUndifferentiated BedrockAlaska Division of Geological & Geophysical SurveysBates CreekBear CreekBedrock CreekBerry CampBirch CreekBonanza CreekBottom Dollar CreekBoulder CreekBuckley Bar CreekButte CreekCircle Hot SpringsCircle Mining DistrictCripple CreekCrooked CreekDeadwoodDeadwood CreekDome CreekEagle CreekEagle SummitEasley CreekFish CreekGold Dust CreekGreenhorn CreekHalf Dollar CreekHoldem CreekHot Springs CreekIndependence CreekKetchem CreekKetchem DomeMammoth CreekMastodon CreekMastodon DomeMiller CreekPinnell TrailPorcupine CreekPorcupine DomePortage CreekPtarmigan CreekSawpit CreekSlate CreekSwitch CreekTraverse CreekTwo-Bit CreekWillow CreekYankee CreekAlaska Division of Geological & Geophysical SurveysMastodon Dome GlaciationWalker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of AmericaPaleozoicQuaternaryTertiaryThis report, map, and/or dataset is 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. The 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. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.Alaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

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FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.The geologic map database was converted to GeMS, quality controlled, and then finalized by DGGS staff Chris Wyatt, Ally Steinleitner, and DGGS contractors. Geologic map conversion to the GeMS standard was funded by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number G21AC10706, 2022, and the State of Alaska General Fund. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.Attribute fields within each feature class are populated using the map symbology and corresponding applicable values from the GeMS and AK GeMS specifications. When known, certainty in attribute interpretation is indicated in the relevant fields. Attribute accuracy varies throughout the map and is scale-dependent.All polygon features were topologically validated according to the AK GeMS geologic mapping schema specifications.This publication is part of a DGGS Report of Investigations (RI). An RI is the completed product of original research and analysis, and RIs use professional cartography and undergo rigorous peer review, editing, and revision.Certainty in feature boundaries or location varies throughout the map. Data fields within each feature class and the accompanying orientation and location confidence lookup tables record the authors' degree of confidence in the location of applicable features.Ekberg, P.G.Hendricks, M.D.Athey, J.E.2021AK GeMS symbology: A description of the AK GeMS style fileMiscellaneous PublicationMP 169Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys7 phttps://doi.org/10.14509/30584paper2021publication dateEkberg, P.G. and others, 2021GIS analysis and digital cartographyHendricks, M.D.Ekberg, P.G.Athey, J.E.Wyatt, W.C.Willingham, A.L.Naibert, T.J.2021AK GeMS data dictionary: A description of the Alaska geologic mapping schemaMiscellaneous PublicationMP 170Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys10 phttps://doi.org/10.14509/30669paper2021publication dateHendricks, M.D. and others, 2021GIS analysis and digital cartographyU.S. Geological Survey National Cooperative Geologic Mapping Program2020GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic mapsTechniques and MethodsTM 11-B10United StatesU.S. Geological Survey1 phttps://dggs.alaska.gov/pubs/id/30585paper2020publication dateU.S. Geological Survey National Cooperative Geologic Mapping Program, 2020GIS analysis and digital cartographyGeologic mapping - This map is based on interpretation of 1:63,600-scale false color infrared aerial photographs taken in August 1990 and August 1991, supplemented by field verification studies in 1993 and 1994. Field notes and sediment samples were collected throughout the area for surficial investigations. Surficial mapping used sources cited in the accompanying map to check and correlate general units. The 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, and samples of organic material were radiometrically analyzed to determine age and glacial provenance.1994GIS analysis and digital cartography - This data distribution package's geologic and geographic features were organized and attributed according to the AK GeMS geologic mapping schema. The data were programmatically transformed to provide download options in three formats: (1) an AK GeMS data package that includes the complete AK GeMS database and associated files, (2) a GeMS data package that is a conversion of the AK GeMS database into the base GeMS standard published by the USGS, and (3) a shapefile data package that includes two simple shapefile representations of the data.Ekberg, P.G. and others, 2021Hendricks, M.D. and others, 2021U.S. Geological Survey National Cooperative Geologic Mapping Program, 20202024vectorUniversal Transverse Mercator60.999600-1470500000.0000000coordinate pair.00000001.00000001MetersNAD27Clarke 18666378206.4294.9786982circle_mining_dist_surficial_ak_gems_db_pkgGeodatabase, layer files, style files, and fontsDGGS and USGScircle_mining_dist_surficial_ak_gems_db_pkgcircle_mining_dist_surficial_gems_db_pkgGeodatabase, layer files, style files, and fontsDGGS and USGScircle_mining_dist_surficial_gems_db_pkgcircle_mining_dist_surficial_gems_shapefile_pkgShapefiles and open data filesDGGS and USGScircle_mining_dist_surficial_gems_shapefile_pkgAlaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysFGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys.https://dggs.alaska.gov/metadata/dggs.extdggs metadata extensions