500,000-year stable carbon isotopic record from Devils Hole, Nevada

The record of carbon-13 (??13C) variations in DH-11 vein calcite core from Devils Hole, Nevada, shows four prominent minima near glacial terminations (glacial-interglacial transitions) V to II. The ??13C time series is inversely correlated with the DH-11 oxygen isotope ratio time series and leads it by as much as 7000 years. The ??13C variations likely record fluctuations in the ??13C of dissolved inorganic carbon of water recharging the aquifer. How such variations are transported 80 kilometers to Devils Hole without obliteration by waterrock reaction remains an enigma. The record may reflect (i) global variations in the ??13C of atmospheric CO2 and, hence, the ??13C of continental biomass or (ii) variations in extent and density of vegetation in the southern Great Basin. In the latter case, ??13C minima at 414, 334, 246, and 133 thousand years ago mark times of maximum vegetation.