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This is a Non-Federal dataset covered by different Terms of Use than Data.gov.

Bedrock geologic map of the northern Fairbanks mining district, Circle Quadrangle, Alaska

Metadata Updated: July 5, 2023

Bedrock geologic map of the northern Fairbanks mining district, Circle Quadrangle, Alaska, Preliminary Interpretive Report 2022-2, presents a 1:50,000-scale bedrock geologic map of the northern Fairbanks mining district, covering parts of the Circle A-4, A-5, B-4, and B-5 quadrangles. The 188-square-mile study area is 55 direct miles northeast of Fairbanks, straddling the Steese Highway between miles 66 and 85. The field area is coincident with the northern tip of the Fairbanks mining district, Alaska's largest historic producer at just less than 17 million troy ounces of gold. This area is within the northeast-oriented trend between plutonic-related gold mineralization in the central Fairbanks mining district and placer gold deposits in the northwest Circle mining district. During June 2007, personnel from the Alaska Division of Geological & Geophysical Surveys (DGGS) and the University of Alaska Fairbanks spent approximately 189 person-days conducting fieldwork in the northeast Fairbanks area. Geologic units are defined by field observations and analysis of samples collected at more than 2,222 stations. Unit descriptions are also based on the petrographic examination and modal analysis of 301 thin sections (this study), 116 thin sections collected in the Circle Quadrangle by the U.S. Geological Survey from 1979-1981, and 26 thin sections from the 1986 Lime Peak-Mt. Prindle project. Metamorphic rocks and younger, unmetamorphosed igneous rocks were primarily defined by chemical composition, examination of hand samples, and petrography. Forty-four rock samples were analyzed for major- and minor-oxide by a commercial analytical laboratory and trace elements by the University of Alaska Fairbanks. These data are used to suggest possible protoliths of metamorphosed and altered rocks, identify types of alteration, and assign trace element-indicated tectonic settings to igneous and metamafic rocks. Non-carbonate carbon in 16 samples was measured by a commercial analytical laboratory. Garnet-biotite geothermometry and garnet-plagioclase-muscovite-biotite equilibria geobarometry were conducted on 16 samples to assess the metamorphic history of the units. Five 40Ar/39Ar ages were used to constrain the timing of igneous events, mineralization, and metamorphism in the northeast Fairbanks area. One U-Pb detrital zircon age provides a maximum age of the metamorphosed sedimentary rocks and for regional unit correlations. Total field magnetic and electromagnetic geophysical data aided our bedrock mapping, especially in areas covered by vegetation and unconsolidated Quaternary deposits. The complete report, geodatabase, and ESRI fonts and style files are available from the DGGS website: http://doi.org/10.14509/30891.

Access & Use Information

Non-Federal: This dataset is covered by different Terms of Use than Data.gov. License: No license information was provided.

Downloads & Resources

Dates

Metadata Date August 29, 2022
Metadata Created Date July 5, 2023
Metadata Updated Date July 5, 2023
Reference Date(s) January 1, 2022 (publication)
Frequency Of Update notPlanned

Metadata Source

Harvested from Alaska Division of Geological and Geophysical Surveys

Additional Metadata

Resource Type Dataset
Metadata Date August 29, 2022
Metadata Created Date July 5, 2023
Metadata Updated Date July 5, 2023
Reference Date(s) January 1, 2022 (publication)
Responsible Party Alaska Division of Geological & Geophysical Surveys (Point of Contact)
Contact Email
Guid 1889aa66-213e-412b-a5d5-c456111f71f5_source
Access Constraints Use Constraints: 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., Access Constraints: This 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).
Bbox East Long -145.982025
Bbox North Lat 65.411456
Bbox South Lat 65.207853
Bbox West Long -146.474345
Coupled Resource
Frequency Of Update notPlanned
Harvest Object Id 1889aa66-213e-412b-a5d5-c456111f71f5
Harvest Source Id 8f77b6d5-f630-4995-bdf3-0aee7158a7f3
Harvest Source Title Alaska Division of Geological and Geophysical Surveys
Licence The State of Alaska makes no expressed 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.
Lineage This lineage was generated by the FGDC CSDGM to 19139 transformation
Metadata Language eng; USA
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": [[[-146.474345, 65.207853], [-145.982025, 65.207853], [-145.982025, 65.411456], [-146.474345, 65.411456], [-146.474345, 65.207853]]]}
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 2007-01-01
Temporal Extent End 2022-01-01

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