A High-Resolution Record of Holocene Climate Change in Speleothem Calcite from Cold Water Cave, Northeast Iowa

High-precision uranium-thorium mass spectrometric chronology and $^{18}$O-$^{13}$C isotopic analysis of speleothem calcite from Cold Water Cave in northeast lowa have been used to chart mid-Holocene climate change. Significant shifts in $\delta^{18}$O and $\delta^{13}$C isotopic values coincide with well-documented Holocene vegetation changes. Temperature estimates based on $^{18}$O/$^{16}$O ratios suggest that the climate warmed rapidly by about 3°C at 5900 years before present and then cooled by 4°C at 3600 years before present. Initiation of a gradual increase in $\delta^{13}$C at 5900 years before present suggests that turnover of the forest soil biomass was slow and that equilibrium with prairie vegetation was not attained by 3600 years before present.