Presented are analytical data from lacustrine sediment cores, retrieved from Lake Nam Co (Tibetan Plateau). The sediment core is a composite of one gravity core, taken with a Rumohr-Meischner gravity corer (63 mm diameter) and a piston core, retrieved using an uwitec piston coring system (http://www.uwitec.at; 90 mm diameter). The composite core labelled comprises a total length of 10.378 m. The cores were obtained at N 30.737417, E 090.790333 at a water depth of 93 m on 2008-09-15. The purpose of obtaining this sediment core was to establish a high-resolution record of climate (monsoonal) and environmental change using multiple proxy data. The dataset comprises analytical data based on sedimentological, inorganic geochemical, mineralogical and isotope-geochemical methods. Specifically: sediment water content & density; magnetic susceptibility; particel size data; quantitative inorganic geochemical data (ICP-OES aqua regia and HCL digestions); semi-quantitative XRF elemental data; carbon, nitrogen, sulfur contents; qualitative mineralogical data; bulk sediment stable carbon and oxygen isotope data.

Dried and ground bulk samples of around 60 to 200 μg were used to measure δ13C and δ18O signals using either a Finnigan GasBenchII connected to a DELTAplusXL isotope ratio mass spectrometer (IRMS) or a Finnigan MAT253 IRMS connected to an automated carbonate-reaction device (KIEL IV) at Helmholtz Centre Potsdam, GFZ. Samples were automatically dissolved with 103% H3PO4 at 72 °C. Replicate analysis of reference material (NBS19) reported standard errors of 0.06‰ for both, δ13C and δ18O relative to VPDB.