Bedrock-geologic map, Alaska Highway corridor, Dot Lake to Tetlin Junction, Alaska

Abstract

The accompanying 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-4, B-4, B-5, B-6, and C-6 quadrangles. It is the central of three bedrock-geologic maps along the Alaska Highway corridor (Werdon and others, 2019; Solie and others, 2019), 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 vegetation, units were interpreted using airborne magnetic and electromagnetic surveys published by DGGS (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 (2011). Active faults in the map area are described in Carver and others (2010). Ages correlate with International Commission on Stratigraphy 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.