Seeking Evidence for Long-term Paleo-ENSO (El Nino-Southern Oscillation) Cycles from Loess-paleosol Sequence During the Last Glacial Period in the Central United States of America

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This award is for an exploratory study of evidence for long-term paleo-ENSO (El Nino-Southern Oscillation) cycles in the central United States, as reflected in evidence for fluctuations the ratio of C3/C4 vegetation types preserved in soils. Stable carbon isotope ratios and soil organic matter will be used as an indicator of the long-term average C3/C4 plant ratios. The stable isotope analyses will be done exclusively on rhizoconcretions (secondary carbonate encrustations on root tubes). Age control will be provided by radiocarbon analyses of soil organic matter and fossil remains.