Bedrock-geologic map, Alaska Highway corridor, Tetlin Junction, Alaska to Canada border

This map shows the distribution of bedrock units exposed at or near the surface in the corridor along the Alaska Highway in parts of the Tanacross A-1, A-2, A-3, and B-3 and Nabesna C-1, D-1, and D-2 quadrangles. It is the easternmost of three bedrock-geologic maps along the Alaska Highway corridor (Werdon and others, 2019a; 2019b), and is part of a multi-year project conducted by the Alaska Division of Geological & Geophysical Surveys (DGGS) between 2006 and 2013. The project focused on investigating and reporting the geology and geologic hazards of the corridor. Bedrock units were mapped and structural elements were measured in the field. Where bedrock units are covered by surficial units and/or vegetation, units were interpreted using airborne magnetic and electromagnetic surveys published by DGGS in 2006 (Burns and others, 2006). Rock names were assigned based on field and petrographic observations, modal-mineral percentages, and interpretations of geochemical data (Werdon and others, 2014). Surficial-geologic map units are shown in Reger and others (2012). An evaluation of potentially active faults in the map area is presented in Koehler and Carver (2012). Ages are based on the International Commission on Stratigraphy’s chronostratigraphic chart (2018). Where bedrock map units are shown with a pattern and queried label, unit designation is interpreted based on nearby geology and geophysical characteristics.

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