T164 Quaternary Climate from the Great Plains to the Great Basin: Geomorphic and Sediment Records across “Great” Landscapes (Posters)

Tuesday, 11 October 2022
9:00 AM - 1:00 PM
Exhibit Hall F

HYDROCLIMATE RESPONSE OF SPRING ECOSYSTEMS TO A TWO-STAGE YOUNGER DRYAS EVENT IN WESTERN NORTH AMERICA

Paper number: T164-1
Program: Technical Sessions
Time: 9:00 AM – 1:00 PM

Authors

Abstract

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially complex, and high-resolution sediment cores in the North Atlantic, western Europe, and East Asia have revealed it unfolded in two distinct stages, including an initial stable climatic period between ~12.9 and 12.2 ka associated with a weakened Atlantic Meridional Overturning Circulation (AMOC) and a second phase characterized by variable conditions until 11.7 ka as the AMOC recovered. Decades of investigations into the climate of western North America during the YD have failed to identify this stepped phenomenon. Here we present hydroclimate data from paleospring deposits in Death Valley National Park (California, USA) that demonstrate unequivocal evidence of two-stage partitioning within the YD event. High groundwater levels supported persistent and long-lived spring ecosystems between ~13.0 and 12.2 ka, which were immediately replaced by alternating wet and dry environments until ~11.8 ka. These results establish the mid-YD climate transition extended into western North America at approximately the same time it was recorded by hydrologic systems elsewhere in the Northern Hemisphere and show that even short-lived changes in the AMOC can have profound consequences for ecosystems worldwide. The ground-truthed proxy data from Death Valley also provide a new benchmark for testing the veracity of existing climate models and will ultimately improve the predictive power of future projections.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-379317

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