Varved Records of Decade- to Century-Scale Climate Variability in the Tropical Atlantic Sector

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This award is to analyze sediments from Lake Bosumtwi to generate a record of tropical West African hydrologic variability back to 3000 years with decadal resolution. In addition, the first tropical record of atmospheric radiocarbon change between 10,000 and 25,000 years will be produced.Previous field work has secured laminated core material back to about 25,000 years at Lake Bosumtwi. A variety of proxy indicators of climate will be analyzed from these sediments to produce a paleohydrologic time series. Charcoal from terrestrial plants will be dated from the varved layers to generate a D14C calibration curve for radiometric dating. The timing of droughts and the natural variability of droughts to this region (West Africa) are important. Better understanding of how the hydrologic history of the region relates to similar records from other regions will advance our overall knowledge of the climate system and allow us to answer many questions regarding interrelationships between low and high latitude and marine and terrestrial climate interactions. The true shape of the atmospheric radiocarbon variation during glacial to deglacial times will be an important advancement for radiocarbon dating.