Paleoclimate in Southern South America and Its Relation to Antarctic Paleoclimates

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The existence of the rapid, Younger Dryas climate event in the southern hemisphere is still a matter of great debate. If this event had detectable effects in the southern hemisphere, then variations in climate caused by internal oscillations may be important for altering climate on a global scale. This proposal requests support to reconstruct the high frequency changes in climate observed in the southern hemisphere during the last glacial-interglacial transition, the time of the Younger Dryas event. The paleoclimate records will be based on pollen assemblage variations and D/H ratios in peat sections. D/H ratios are a function of temperature and moisture availability. The PIs wish to calibrate the D/H variations for this region and then use the calibration to quantify the variations in the past. Thus the D/H ratios will supplement the pollen data and help to identify what climate parameters changed during the deglaciation. This research is important because we do not yet know the history of climate in the southern hemisphere. It is necessary to understand the extent of climate change in this hemisphere before we fully understand the mechanisms of abrupt climate change.