Data release for Evidence of glacial activity during MIS 4 in the Rocky Mountains, Colorado, USA

The Ziegler Reservoir fossil site near Snowmass Village, Colorado (USA) provides a rare opportunity to examine environmental conditions in the Rocky Mountains during marine isotope stage (MIS) 4 (71–57 ka). Although recognized as a global-scale cold event, MIS 4 is typically absent from Rocky Mountain glacial chronologies because the geologic evidence was either covered or destroyed during the subsequent, and larger, MIS 2 (Pinedale; 29–14 ka) glaciation. The Ziegler Reservoir site is perched on a ridge above Pinedale glacial limits, which allowed for the preservation of a long-lived sequence of predominantly eolian sediments that spans from late MIS 6 (ca. 140 ka) through early MIS 3 (ca. 55 ka). Sediments dating to MIS 4 exhibit [...]