| Summary: | A multi-proxy sedimentological study was completed on a section of a sediment core from Lake Elsinore, California, that spans the late-Glacial to Holocene transition (17,619–9,587 calendar years before present [cy BP]). The results of the study provide the first high resolution terrestrial climate record from Southern California that spans this interesting interval In Earth's climate history. The results indicate that the depositional and climatic environments of Lake Elsinore changed significantly across this transition. Interpretation of the results suggests that the lake was relatively deep during the last glacial period, but then became relatively shallow near the beginning of the Holocene interglacial. Interpretation of the results also suggests that the Lake Elsinore deglaciation sequence was characterized by a two step drying trend, which is explained here by changes in North American ice sheet extent and variations in the intensity of the Atlantic Meridional Overturning Circulation. Together, the latter two forcings acted to modulate the average position of the circumpolar jet stream, the mean latitude of the Intertropical Convergence Zone, and their combined impacts on the Northern Hemisphere winter storm tracks, which determine the annual hydrologic budget of Southern California. A comparison of the Lake Elsinore record with other regional paleoclimate records shows strong evidence for synchronous hydrologic change between study sites throughout southwestern North America. Additionally, a comparison of the Lake Elsinore record with the Greenland ice core record provides evidence for a coupling between changes in climate over the North Atlantic and Southern California during the late-Glacial to Holocene transition.
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