Comparison of the Quaternary Stratigraphy of the Alps and Rocky Mountains ,

Abstract

Comparison of the glacial and periglacial deposits and soils of the Alps and Rocky Mountains suggests the following correlations. The Donau, Günz, and Mindel are correlated with the Washakie Point (Nebraskan), Cedar Ridge (Kansan), and Sacagawea Ridge (Illinoian). These glaciations are separated and followed by interglacials represented by thick deeply weathered soils, the last being the Mindel/Riss, or Sacagawea Ridge/Bull Lake (Sangamon). The Riss I (Paar) and Riss II (type Riss) Glaciations are correlated with the early and late advances of the Bull Lake Glaciation (early Altonian), and are believed to be different glaciations separated and followed by short interglacials represented by soils of intermediate development at these latitudes. The Alt-Würm period of restricted ice in the Alps is represented only by local unnamed deposits in the Rocky Mountains. In the Alps, at least three interstadial soils occur between the Riss/Würm soil and the oldest Main Würm end moraine. These coincide in time respectively with the beginning and end of the Port Talbot II interstadial and with Plum Point interstadial. The three major end moraines of the Main Würm are correlated with three or locally more end moraines of the early and middle stades of the Pinedale (Woodfordian). Moraines of the late stade of the Pinedale are equivalent to the late glacial and early postglacial moraines of post-Würm but pre-Atlantic age in the Alps.K-Ar dating and tephrochronology in the Rockies suggest that the Washakie Point ended about 1.2 m.y. B.P., the Cedar Ridge about 700,000 B.P., the Sacagawea Ridge about 180,000 B.P., the last great interglacial about 130,000 B.P., and the interglacial separating early and late Bull Lake about 80,000 B.P. Radiocarbon dates from the Alps suggest that the Riss/Würm was about 70,000–60,000 B.P., and that Alt-Würm interstadials occurred at >50,000, 45,000–40,000, 34,000–32,000, and 28,000 B.P. Radiocarbon dates from rock shelter deposits in France indicate minor interstadials in the Main Würm at 21,000–20,000 B.P. and about 17,000 B.P. Both the Main Würm and Pinedale ended about 11,800 B.P.