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

该奖项是为了奖励对美国中部长期古厄尔尼诺-南方涛动周期证据的探索性研究，这反映在土壤中保存的C3/C4植被类型比率波动的证据中。稳定碳同位素比率和土壤有机质将作为C3/C4植物长期平均比率的指标。稳定同位素分析将专门用于根结（根管上的次生碳酸盐结壳）。土壤有机质和化石残骸的放射性碳分析将提供年龄控制。

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.