Surficial geology of Alaska Highway Corridor, Robertson River to Tetlin Junction, Alaska

During 2008-2010, the Alaska Division of Geological & Geophysical Surveys continued a program, begun in 2006, of reconnaissance mapping of surficial geology in the proposed natural-gas pipeline corridor through the upper Tanana River valley, a 12-mi-wide (19.3-km-wide) area that straddles the Alaska Highway through the upper Tanana River valley from the western boundaries of the Tanacross B-6 and C-6 Quadrangles near the mouth of the Robertson River eastward to the eastern boundaries of the Tanacross A-4 and B-4 Quadrangles near Tetlin Junction. Mapping during 2008-2010 in the Tanacross Quadrangle linked with mapping of surficial geology completed in the Big Delta and Mt. Hayes quadrangles in 2006-2007. Surficial geology was initially mapped in this second corridor segment by interpreting ~1:65,000-scale, false-color, infrared aerial photographs taken in July 1978, August 1980, and July 1983.Verification of photo mapping was accomplished during the 2008-2010 summer field season, when map units were described, soil pits were hand dug, and samples were collected for analyses.