High-resolution records of geochemical data from four lakes in the Greater Yellowstone region were used to investigate watershed and lake history during the late-glacial and early-Holocene periods. Clastic input to regional lakes was high and variable during the early stages of lake development, when the surrounding landscape was geomorphically unstable and sparsely vegetated, and it decreased as vegetation gradually developed in each catchment. The decrease of clastic input was not regionally synchronous but occurred in a time-transgressive pattern from south to north. Long-term organic matter concentration and diatom production were inversely related to catchment erosion during the early stages of lake development and increased as temperatures warmed and in-lake nutrient concentrations increased. Similarly, calcite production usually was low following lake formation and increased over time, driven by climate change and its associated influences on lake-level, algal production, and lake thermal structure. Overall differences in the timing and pattern of geochemical change indicate that once the landscape had stabilized following deglaciation, changes in the geochemical character of the sediments were strongly influenced by local factors.
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Acknowledgements This research was supported by National Science Foundation Grants EAR-0816576 to S. Fritz and EAR-0818467 to C. Whitlock, as well as a GSA Graduate Student Research grant to Y. Lu. We thank C. Hendrix and S. Gunther (Yellowstone National Park) for logistical support, and T. Spanbauer, D. Navarro, and J. Giskaas for field assistance.
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- Watershed history
- Western North America
- X-ray fluorescence