Geology of the Sleetmute A-5, A-6, B-5, and B-6 quadrangles, southwestern Alaska

Metadata Updated: October 4, 2025

Geology of the Sleetmute A-5, A-6, B-5, and B-6 quadrangles, southwestern Alaska, Professional Report 99, presents a compilation geologic map of the Chuilnuk Mountains and Kiokluk Mountains in the Kuskokwim Mountains area of southwestern Alaska. Geologic mapping of the Sleetmute quadrangles in southwestern Alaska utilized detailed topographic maps, aerial photographs, and field data from U.S. Geological Survey studies, with key contributions published in 1984 and supplemented by Alaska DGGS data files. The region's geology spans from the Late Proterozoic to the Holocene, with the oldest rocks informally grouped under the broadly defined Holitna Group. Most of the area is underlain by the Kuskokwim Group, a thick sequence of marine turbidites primarily dated to the Late Cretaceous. Overlying this is the Holokuk Basalt, a Late Cretaceous volcanic unit associated with granodiorite intrusions, followed by younger dikes and olivine basalt dated at 38 Ma. Quaternary deposits record four glacial advances, and the area exhibits complex folding and faulting tied to the Denali-Farewell fault system. The lower Kuskokwim region is rich in mineral resources, including placer deposits of gold and tungsten, and vein and greisen deposits containing mercury, antimony, tin, and other metals. Hydrothermal quartz veins near Fortyseven Creek host gold and scheelite, likely formed by a rhyolite intrusion. Mercury and antimony deposits, such as the Mountain Top site, occur in sheared and brecciated rocks, possibly linked to hot spring activity. Tin is found in quartz-tourmaline veins and stockworks near pluton contacts, with mineralized zones showing distinct downstream geochemical signatures.The complete report, geodatabase, and ESRI fonts and style files are available from the Alaska Division of Geological & Geophysical Surveys website: http://doi.org/10.14509/2280.

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

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Dates

Metadata Date	October 2, 2025
Metadata Created Date	October 4, 2025
Metadata Updated Date	October 4, 2025
Reference Date(s)	January 1, 1995 (publication)
Frequency Of Update	notPlanned

Metadata Source

ISO-19139 ISO-19139 Metadata
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FGDC Original FGDC Metadata
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Harvested from Alaska Division of Geological and Geophysical Surveys

Additional Metadata

Resource Type	Dataset
Metadata Date	October 2, 2025
Metadata Created Date	October 4, 2025
Metadata Updated Date	October 4, 2025
Reference Date(s)	January 1, 1995 (publication)
Responsible Party	Alaska Division of Geological & Geophysical Surveys (Point of Contact)
Contact Email	dggspubs@alaska.gov
Guid	04835eb5-6d01-4937-920f-3d948282f357_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	-157.477051
Bbox North Lat	61.505893
Bbox South Lat	60.993776
Bbox West Long	-158.261453
Coupled Resource
Frequency Of Update	notPlanned
Harvest Object Id	04835eb5-6d01-4937-920f-3d948282f357
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": [[[-158.261453, 60.993776], [-157.477051, 60.993776], [-157.477051, 61.505893], [-158.261453, 61.505893], [-158.261453, 60.993776]]]}
Progress	completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester	True
Temporal Extent Begin	1955-01-01
Temporal Extent End	2026-01-01

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