δ18O and δ13C from sediment core of Lake Alchichica in Mexico

The proxy data are measured from a 57-cm long sediment core collected from Lake Alchichica (19° 24' 38 N, 97° 24' 14 W, 2322 masl) at a water depth of ~ 60 m using a Uwitec® coring device equipped with a 9-cm coring tube. The core was split lengthwise, analyzed using XRF core scanning, and subsampled. A Bayesian chronology was created using 210Pb data and three 14C dates. For stable isotope geochemistry (δ¹⁸O and δ¹³C) of bulk sediments, samples collected at 1 cm intervals were analyzed at MARUM, University of Bremen, using a Finnigan MAT252 mass spectrometer with a Kiel III carbonate preparation device. Results are reported in delta notation (δ) relative to VPDB. Calibration involved a house standard (Solnhofen limestone) referenced to NBS 19 calcite, with standard deviations of 0.06‰ for both δ¹³C and δ¹⁸O.