Surficial geology of the Alaska Highway corridor, Tetlin Junction to Canada border, Alaska

During 2009, 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. The study area is a 12-mi-wide (19.3-km-wide) area that straddles the Alaska Highway from the western boundaries of the Tanacross B-3 and A-3 quadrangles near Tetlin Junction eastward to the eastern boundaries of the Nabesna D-1 and C-1 quadrangles along the Canada border. Mapping during 2008-2009 in the Tanacross and Nabesna quadrangles linked with the mapping completed in the Tanacross, Big Delta and Mt. Hayes quadrangles in 2006-2008. Surficial geology was initially mapped in this third corridor segment by interpreting ~1:65,000-scale, false-color, infrared aerial photographs taken in July 1978 and August 1981 and plotting unit boundaries on acetate overlays. Verification of photo mapping was accomplished during the 2008 and 2009 summer field seasons, when map units were described, soil pits were hand dug, and samples were collected for analyses.