U-Pb zircon ages from bedrock samples collected in the Tanacross and Nabesna quadrangles, eastern Alaska

This Alaska Division of Geological & Geophysical Surveys (DGGS) Preliminary Interpretive Report presents uranium-lead (U-Pb) ages of zircons from 37 igneous and metamorphic samples collected during the 2019 field season in support of a 4,800-sq-km (1,860-sq-mi) bedrock geologic map of eastern Interior Alaska surrounding Mount Fairplay and the Ladue River drainage. The area lies north of the Alaska Highway and is approximately 65 km (40 mi) east of Tok, Alaska; it runs west from the Alaska-Yukon border to encompass the Taylor Highway. DGGS and U.S. Geological Survey (USGS) staff identified this area as having underexplored potential to host deposits of critical minerals, including rare earth elements (REE), uranium, niobium, zirconium, tin, tungsten, bismuth, and rhenium, as well as conventional mineral resources including gold, copper, molybdenum, lead, zinc, and silver. The goal of this U-Pb isotopic study is to better understand the Devonian through Paleogene magmatic and tectonic events, which have been linked to most of the known mineralization in the Yukon-Tanana Uplands. The Mount Fairplay and Ladue River areas are characterized by amphibolite- to greenschist-facies metamorphic rocks-the Lake George assemblage, Ladue River unit, and the Klondike assemblage-which have Mississippian-Devonian and Permian protolith ages. Voluminous volcanic and plutonic rocks of varying composition and texture from the mid-Cretaceous (ca. 100-115 Ma), Late Cretaceous (ca. 65-71 Ma), and Paleogene (ca. 57-58 Ma) magmatic episodes were observed to be emplaced in both the Lake George and Ladue River metamorphic units. Alaska DGGS and the USGS staff have identified both generations of Cretaceous magmatism as having potential to host deposits of the critical minerals mentioned above. All components of this data release are available on the DGGS website: http://doi.org/10.14509/30732.

Data e Risorse

Campo Valore
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)."]
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bbox-north-lat 63.729500
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contact-email dggspubs@alaska.gov
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dataset-reference-date [{"type": "publication", "value": "2021-01-01"}]
frequency-of-update notPlanned
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."]
metadata-date 2021-08-11
metadata-language eng; USA
metadata_type geospatial
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  • AmeriGEOSS
  • National Provider
  • North America
Tag
  • allochthon
  • amerigeo
  • amerigeoss
  • amphibolite
  • analyses
  • bedrock
  • big-creek
  • big-timber-creek
  • chicken-creek
  • ckan
  • correlation
  • cretaceous
  • dennison-fork
  • devonian
  • dggs
  • diorite
  • fortymile-mining-district
  • geo
  • geochronology
  • geologic
  • geology
  • geoss
  • gneiss
  • granite
  • granodiorite
  • greenschist
  • igneous
  • igneous-rocks
  • interpretation
  • isotopes
  • jarvis-belt
  • klondike-assemblage
  • ladue-river
  • ladue-river-unit
  • lake-george-assemblage
  • lead
  • logging-cabin-creek
  • mcarthur-creek
  • mesozoic
  • metamorphic
  • metamorphic-rocks
  • metamorphism
  • metavolcanic-rocks
  • methods
  • mineralogy
  • minerals
  • mining
  • mississippian
  • molybdenum
  • moosehorn-ridge
  • mount-fairplay
  • national
  • north-america
  • orthogneiss
  • paleogene
  • paleozoic
  • permian
  • phanerozoic
  • plutonic
  • plutons
  • porphyry
  • precambrian
  • proterozoic
  • provenance
  • rhyolite
  • rocks
  • schist
  • south-fork-ladue-river
  • terranes
  • triassic
  • tuff
  • tungsten
  • united-states
isopen False
metadata_created 2025-11-19T20:24:45.782915
metadata_modified 2025-11-19T20:24:45.782921
notes This Alaska Division of Geological & Geophysical Surveys (DGGS) Preliminary Interpretive Report presents uranium-lead (U-Pb) ages of zircons from 37 igneous and metamorphic samples collected during the 2019 field season in support of a 4,800-sq-km (1,860-sq-mi) bedrock geologic map of eastern Interior Alaska surrounding Mount Fairplay and the Ladue River drainage. The area lies north of the Alaska Highway and is approximately 65 km (40 mi) east of Tok, Alaska; it runs west from the Alaska-Yukon border to encompass the Taylor Highway. DGGS and U.S. Geological Survey (USGS) staff identified this area as having underexplored potential to host deposits of critical minerals, including rare earth elements (REE), uranium, niobium, zirconium, tin, tungsten, bismuth, and rhenium, as well as conventional mineral resources including gold, copper, molybdenum, lead, zinc, and silver. The goal of this U-Pb isotopic study is to better understand the Devonian through Paleogene magmatic and tectonic events, which have been linked to most of the known mineralization in the Yukon-Tanana Uplands. The Mount Fairplay and Ladue River areas are characterized by amphibolite- to greenschist-facies metamorphic rocks-the Lake George assemblage, Ladue River unit, and the Klondike assemblage-which have Mississippian-Devonian and Permian protolith ages. Voluminous volcanic and plutonic rocks of varying composition and texture from the mid-Cretaceous (ca. 100-115 Ma), Late Cretaceous (ca. 65-71 Ma), and Paleogene (ca. 57-58 Ma) magmatic episodes were observed to be emplaced in both the Lake George and Ladue River metamorphic units. Alaska DGGS and the USGS staff have identified both generations of Cretaceous magmatism as having potential to host deposits of the critical minerals mentioned above. All components of this data release are available on the DGGS website: http://doi.org/10.14509/30732.
num_resources 9
num_tags 73
title U-Pb zircon ages from bedrock samples collected in the Tanacross and Nabesna quadrangles, eastern Alaska