Surficial-geologic map, Delta Junction to Dot Lake, Alaska Highway corridor

The Rosa-Keystone Dunes Field: The geoarchaeology and paleoecology of a late Quaternary stabilized dune field in Eastern Beringia

“…Two late Pleistocene regional glacial periods, the Delta and Donnelly glaciations, are pertinent to the discussion of loess and dune and sand sheet development in the mTV (Hamilton, 1973; Péwé and Reger, 1983). The Delta and Donnelly glaciations (70–40,000 and 25–16,600 years ago, respectively), are recognized by moraines and glacial drift situated on the north side of the Alaska Range (Matmon et al, 2010; Reger et al, 2008; Ten Brink and Waythomas, 1985). Katabatic winds derived from the Delta and Donnelly massive ice sheets created increasing wind frequency and intensity of eolian erosion and deposition across the Tanana basin (Muhs and Budhan, 2006; Péwé and Reger, 1983; Thorson and Bender, 1985).…”

“…Katabatic winds derived from the Delta and Donnelly massive ice sheets created increasing wind frequency and intensity of eolian erosion and deposition across the Tanana basin (Muhs and Budhan, 2006; Péwé and Reger, 1983; Thorson and Bender, 1985). Péwé and others (Péwé, 1975; Reger et al, 2008) have hypothesized that an immense amount of fluvial deposition within the Tanana Valley occurred during glacial periods and provided sediment sources for subsequent wind deposition and the growth of dune fields and accumulation of sand sheets and loess covering the hills.…”

“…The SCF is a low-lying alluvial plain or terrace formed by the aggradation of the Tanana River during the height of the Donnelly glaciation (Last Glacial Maximum (LGM); Reger et al, 2008). Shaw Creek and its tributaries drain the Yukon-Tanana Uplands into the Tanana River in this region.…”

“…A Delta-aged terminal moraine, less than 16 km south of the SCF, was dissected during the subsequent interglacial period, creating a gap among till deposits (Reger et al, 2008). Donnelly-aged terminal moraines are situated in the Delta River Valley, approximately 32–48 km south of the SCF, and fan deposits associated with this period fill gaps in the Delta-aged terminal moraine.…”

“…Donnelly-aged terminal moraines are situated in the Delta River Valley, approximately 32–48 km south of the SCF, and fan deposits associated with this period fill gaps in the Delta-aged terminal moraine. A period of massive alluviation during the Donnelly glaciation forced the Tanana River northward toward the southern bases of the Uplands (Reger et al, 2008). Gravel, sand, and silt from the Donnelly-aged outwash fan underlie the modern surface of the SCF (Reger et al, 2008).…”