Post-Glacial Radiocarbon Ages for the Southern Cordilleran Ice Sheet

Abstract

The Pleistocene Cordilleran Ice Sheet (CIS) formed over mountainous terrain in northwestern North America, and last reached a maximum extent around 15 to 17 ka BP. Following this maximum, the ice sheet began to diminish in size. Retreat was rapid in some sectors, but was punctuated by still-stands and readvances in other sectors. Geochronology of CIS retreat is key for understanding the pace and style of this deglaciation, and for testing hypothesized feedbacks between the changing ice sheet and the ocean, atmosphere, and solid earth. One method of reconstructing ice sheet retreat relies on radiocarbon ages of immediate post-glacial organic material. Such ages are minima for deglaciation and are often utilized to infer the timing of ice sheet retreat. This paper describes a database of post-glacial radiocarbon dates on non-marine carbon for the region from 47° to 52°N that was once covered by the southern CIS. The data were collected from published literature. Each entry includes name, lab ID, location, elevation, the material dated, its stratigraphic context, the event dated, additional details, and a reference to the original data. This information is useful for validating numerical models of the CIS, for connecting CIS evolution to climate change, and for reconstructing late Pleistocene environments of the Pacific Northwest.

Keywords

• Cordilleran Ice Sheet
• Deglaciation
• Post-glacial
• Radiocarbon
• Last Glacial Maximum
• Continental Ice Sheets