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High-Resolution Evidence for Early Holocene Climate Variability in Mud Pond, NY

Session: Lakes of the World Through Space and Time: Archives of Climate, Paleoenvironments, Ecosystems, Geohazards, and Economic Resources (Posters)

Presenting Author:

Corra S. Lewis

Authors:

Lewis, Corra S¹, Curtin, Tara M², Finkelstein, David B³

(1) Geology Department, Colorado College, Colorado Spring, CO, USA, (2) Geoscience Department, Hobart & William Smith Colleges, Geneva, NY, USA, (3) Geoscience Department, Hobart & William Smith Colleges, Geneva, NY, USA,

Abstract:

During the early Holocene, abrupt climate shifts were triggered by disruptions to the Atlantic Meridional Overturning Circulation caused by freshwater discharge from glacial lake outburst floods. Between ~11.5 and 7 ka, multiple outbursts from Glacial Lake Agassiz released large volumes of meltwater into the North Atlantic Ocean, triggering episodic regional cooling. However, their climatic impact on the northeastern United States remains poorly constrained, in part due to the low temporal resolution of previously studied sediment records. To evaluate the climatic effects of these events in the Finger Lakes region of New York, we analyzed a 7.7-meter sediment core from Mud Pond. The core captures a transition from silt (7.15–7.7 m) to laminated and bedded carbonate mud rich in mollusks (3.2–7.15 m) overlain by peat (0–3.2 m) that record environmental change since ~13.5 cal ka BP. We used high-resolution ITRAX X-ray fluorescence (XRF) core scanning at 0.5-mm intervals, loss-on-ignition (LOI) at up to 1-cm intervals, and mollusk assemblage analysis every 10 cm. Carbonate content derived from LOI is strongly correlated with XRF-derived Ca/Ti ratios (r = 0.9), supporting the use of Ca/Ti as a proxy for warm summertime water temperatures. Intervals corresponding to known Lake Agassiz outburst floods are marked by 10–20% declines in carbonate content, suggesting brief episodes of cooler conditions. These intervals also show faunal shifts toward cold-adapted gastropod species. Regional comparison reveals that both Mud Pond and nearby Seneca Lake exhibit similar declines in carbonate content, supporting the interpretation of a broader climate response across the northeastern U.S. to freshwater forcing events in the North Atlantic. Additional carbonate declines in Mud Pond and Seneca Lake not associated with known outburst floods may reflect local or regional climatic variability.