TESTING POST-GLACIAL ENVIRONMENTAL CHANGE IN THE SNOWY MOUNTAINS, AUSTRALIA, WITH A SUITE OF NEW LAKE SEDIMENT CORES

Tarns in the highest part of the Snowy Mountains, the only glaciated region in mainland Australia, have captured sediments continuously since deglaciation, ca. 18,000 yr B.P. Analysis of an 8.2 m core from the largest of these, Blue Lake, demonstrates that the lakes preserve high-resolution, high-fidelity sedimentary records of environmental change since the onset of Termination 1. In particular, the core indicates that southeastern Australia experienced several dramatic shifts in climate (cold/dry vs. warm/wet) between ca. 18-11 ka, the last two of which may correlate to the Antarctic Climate Reversal and Younger Dryas. Although the Holocene portion of the core records a more consistent climate (warm/wet overall), it is punctuated by two notable periods of somewhat cooler/dryer conditions at ca. 10.8-9.7 ka and ca. 2.2-1.2 ka.

We plan to test and amplify the results of this single core by collecting a suite of new sediment cores from two other tarns in the area (Club Lk and Lk Albina) this August (2022). Because we plan to collect multiple cores from each lake, we anticipate that they will provide more robust age constraints than are available for the Blue Lk core, which will in turn allow us to refine the timing and possible correlations of the events recorded in the Blue Lk sediments. Furthermore, because Blue, Club, and Albina all occupy cirques in different drainages, the new cores will allow us to assess the local vs. regional influences and coherence of the climatic events recorded in the Blue Lk core. Although detailed analyses of the new cores will just be commencing in October, we will present our initial results of the coring at the meeting.