Surficial geological map (1:50,000 scale) of the Yukon and Sixtymile river valleys (parts of 115O/5, 12 and 115 N/9), western Yukon, including marginal notes on surficial geology, geomorphology and placer occurrences.

Glacial history reconstructions and geomorphic mapping in the North McQuesten River, Dublin Gulch, and Keno Hill map areas indicate a succession of less extensive glaciations. From oldest to youngest, the main glacial episodes are the pre-Reid (multiple glacial episodes), Reid and McConnell glaciations. The surficial geology of the study area is dominated by deposits of the Reid and McConnell glaciations. Pre-Reid glacial deposits are mostly confined to infrequent erratics on plateau areas above the Reid glacial limit. Glacial limit mapping indicates that ice flow patterns were similar in both the Reid and McConnell glaciations. Valleys aligned parallel with glacial ice flow are broad and U-shaped with significant glacial deposits in valley bottoms. In contrast, valleys aligned transverse to glacial ice flow are narrower and have a more V-shaped morphology. This relationship appears to be a controlling factor on the distribution of placers in the study area. Numerous drainages were analyzed for their placer potential in each of the three map areas. Their potential was based on geomorphic evaluations, glacial history, geochemistry, bedrock geology, and historic records. A concentration of potential placer creeks were identified in the Keno Hill/Mayo Lake area. Fewer prospective creeks were identified in the Dublin Gulch and North McQuesten River map areas.

Alaska Division of Geological & Geophysical Surveys (DGGS) has conducted 1:63,360-scale geologic mapping of the Sagavanirktok B-1 Quadrangle (640 square km�equivalent to four 7.5 minute quadrangles). This mapping project reinterprets micropaleontologic correlations for 17 Sagavanirktok Quadrangle wells, and reprocesses data from the one publicly-available seismic line. Surface geologic mapping, subsurface-to-surface stratigraphic age control, and seismic framework are required to reliably decipher the complex geology of this key area of the Brooks Range. Outcrops within the Sagavanirktok B-1 Quadrangle are the closest surface expressions of Prudhoe Bay source and reservoir rocks. This study yields critical petroleum-related information from these surface exposures, and how they relate to the area subsurface stratigraphy.