Bedrock geologic maps of the Mount Harper-Middle Fork area, Volkmar River-Healy River area, Goodpaster River-Shaw Creek area, and the Richardson Mining District, Alaska

Bedrock geologic maps of the Mount Harper-Middle Fork area, Volkmar River-Healy River area, Goodpaster River-Shaw Creek area, and the Richardson Mining District, Alaska, Preliminary Interpretive Report 2025-2, presents bedrock geologic mapping of a 7,988-sq-km (3,084-sq-mi) area north of the Richardson and Alaska highways between the communities of Salcha and Dot Lake in the Yukon-Tanana Uplands (YTU) of eastern Interior Alaska. The project's goals are: to better understand the geologic framework of known mineralization, to support the exploration and discovery of new mineral resources in the area, and to build scientific understanding of the geology of the YTU, one of Alaska's most active and important mineral belts. The project area has been a focus of gold exploration for several decades but also has additional significance for its potential to host critical minerals such as antimony, bismuth, tellurium, and tungsten. Project work was completed by Alaska Division of Geological & Geophysical Surveys (DGGS) staff and collaborators during the 2022 and 2023 summer field seasons and draws on additional published and unpublished work completed during prior years by DGGS, University of Alaska, and U.S. Geological Survey staff. The project area is divided into four geologic map sheets, listed from east to west: the Mount Harper-Middle Fork area, the Volkmar River-Healy River area, the Goodpaster River-Shaw Creek area, and the Richardson Mining District. The map units used across the four maps are described in this report. The complete report, geodatabase, and ESRI fonts and style files are available from the Alaska Division of Geological & Geophysical Surveys website: http://doi.org/10.14509/31648.

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Organization: State of Alaska