2022/05/18 by Carol B. Griggs, C.F. Michael Lewis, C F M Lewis +2 · 1 citation
Earth and Planetary Sciences · Environmental Science · #Geology and Paleoclimatology Research #Tree-ring climate responses #Landslides and related hazards
paper · pdf · doi:10.1017/qua.2021.76
Abstract A unique regional climate progression, ca 14.2–11.5 cal ka BP, in the eastern Great Lakes region of North America is suggested by subfossil logs, high-resolution 14 C dates, and established proxy records in New York, USA. The progression began with a northern boreal-type climate ca. 14.2–13.1 ka coeval with the expansion of Lake Iroquois, a transition to a southern boreal-type climate ~13.1–12.9 ka that coincided with the transition of Lake Iroquois into progressively lower lake levels, and a continuation of the southern boreal-type climate ~12.9–11.5 ka. These conditions and changes are evident in the tree rings and relative dominance of tamarack ( Larix laricina ) and spruce species ( Picea spp.) plus the presence of black ash ( Fraxinus nigra ) as the only thermophilous species. Together they suggest variations in atmospheric moisture levels, surface winds, temperature extremes, and/or an enhanced seasonality over time. Here we propose that the evolution of the glacial Great Lakes and their interactions with ice sheets, meltwater, winds, and regional topography created a regional glacial lake-effect climate, 14.2–11.5 cal ka BP, that was opposite to the established warming Bølling-Allerød–cold Younger Dryas climate progression.