Centennial Valley, southwestern Montana
A ca. 20,000-yr-old sediment core from Lower Red Rock Lake in the Centennial Valley of southwest Montana was obtained to reconstruct the vegetation, climate, and environmental changes during and following the late-Pinedale Glaciation. Examination of the first arrival of Pseudotsuga in pollen records throughout the region shows that its arrival was later at sites on the Atlantic side of the Continental Divide as compared to sites on the Pacific side. The geographic pattern suggests that the Continental Divide posed a topographic or climate barrier in the late-glacial period, delaying the migration of Pseudotsuga menziesii from glacial refugia.
Ovando Valley, west-central Montana
Further research on the fire and climate history of western Montana is being executed by research associate Rod Benson, M.J. Charitable Murdock Trust fellow. The goal of his research is to learn more about the cause(s) of past fires in west-central Montana. He is doing a high-resolution fire-history study by examining particulate charcoal preserved in sediment cores from Jones Lake near Ovando. Prior radiocarbon dating, geochemistry and pollen studies will be compared to Rod's study to gain a better understanding of climate and vegetation changes over the last 13,000 years in the Ovando Valley.