CLIMATE TRANSITION DURING THE MID-HOLOCENE: EVIDENCE FROM THE SEDIMENT OF SENECA LAKE, NEW YORK

Erosional truncation of late Holocene strata within Seneca Lake, as indicated by preliminary high-resolution (2-12 kHz) seismic profiling (Edge Tech X-Star Subbottom System) and piston core sediment analyses, suggests a dynamic climatic transition occurred during the mid-Holocene.

Presently, significant currents (up to 30cm/sec, 1m above the lake floor, water depths of 66m) associated with wind and internal wave driven activity are found within Seneca Lake. Sediment erosion during the Holocene is observed approximately 60m below the lake surface. Sediment erosional truncation of late Holocene sediment suggests that climate abruptly changed after or near the Hypsithermal (mid-Holocene maximum summer insulation event) and affected sediment erosion and deposition.

This study analyzes high-resolution seismic profiles and piston cores of sediment collected aboard the research vessel HWS Explorer to further investigate Holocene climate change. The seismic profiles delineate a map of Holocene sediment thickness that focuses on a comparison of early and late Holocene sediment section characteristics and amounts. The sediment cores are described and analyzed for magnetic susceptibility, water content, bulk carbonate, and total organic carbon (TOC) to assess the relative truncation of early and late Holocene sections. Preliminary data indicate that late Holocene sediment are significantly more truncated than the early Holocene sediment. Such truncation suggests that atmospheric circulation changed to a more dynamic environmental system in the Finger Lakes region of North Eastern United States during the mid-Holocene. This dynamic climatic transition may be due to a southward shift in the Jet Stream at this time.