24 Limnogeology and Paleoclimate

Friday, 8 April 2022
8:00 AM - 12:00 PM
North Meeting Room 201/202

A HIGH-RESOLUTION RECORD OF MULTIPLE DROUGHTS DURING THE LATE HOLOCENE DRY PERIOD FROM JUNE LAKE, CALIFORNIA

Paper number: 24-14
Program: Theme Sessions
Time: 11:10 AM – 11:30 AM

Authors

Abstract

The Late Holocene Dry Period (LHDP) has been documented as a multi-century drought in limnological and meadow records throughout the Great Basin, though its timing and resolution are not firmly established across the region. Here we present a well-dated geochemical record of at least three distinct dry pulses within the larger LHDP from the high-resolution sedimentary record of June Lake, a small glacial scour basin at the physiographic boundary between the Great Basin and the eastern Sierra Nevada of California. Specifically, we interpret intervals of pronounced carbonate accumulation, as recorded by high total inorganic carbon, elevated δ18O values (reflective of lake water evaporation), and peaks in high-resolution Ca/Ti derived from scanning x-ray fluorescence (XRF), as periods of extended drought. We find these peaks centered at ~3200, 2600, and 2100 cal BP in all of these indicators. Additionally, another peak in carbonate accumulation occurs at ~3700 cal BP, which may suggest an earlier onset for the LHDP than previously recognized. The June Lake archive further demonstrates that the effects of the LHDP extended to the eastern Sierra. In addition to the centennial-scale droughts recorded by the carbonate isotopic data, the high-resolution Ca/Ti record provides the potential to identify droughts at the sub-decadal scale. The 4600-year archive also records dry intervals during the Medieval Climate Anomaly, and the Industrial Era associated with contemporary warming. Such robustly dated, high-resolution records are increasingly important for this region, where dwindling snowpack and drought continue to plague California’s headwaters.

Geological Society of America Abstracts with Programs. Vol. 54, No. 4

doi: 10.1130/abs/2022NC-375333

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