Isotopic analyses of oxygen, carbon and deuterium conducted on lakewater samples collected from Moutonnee, Ablation and Citadel Bastion Lakes on Alexander Island.

Sediment trap and delta samples were taken from Moutonnee Lake on Alexander Island during the 2001-2002 field season. Samples were analysed for grain size, Carbon and Nitrogen content and isotopic Carbon content. Delta samples were also analysed for luminescence dating.

The dataset comprises reconstructed temperature and tephra deposits age data from Yanou Lake, Fildes Peninsula, King George Island, South Shetland Islands. Data are calibrated to the 2020 radiocarbon calibration curves. The Antarctic and global glycerol dialkyl glycerol tetraether (GDGT) lipid biomarker temperature calibration are included. GDGT MSAT (mean summer air temperature) data was obtained by recalibrating the Pearson et al. (2011) global and Foster et al. (2016) Antarctic lake surface GDGT MSAT datasets. This dataset includes updates with new calibration of data originally published in Roberts et al. (2017). These revisions were funded as part of the IMCONet (FP7 IRSES, action no. 318718) program led by Doris Abele (AWI); the Natural Environment Research Council (NERC/BAS-CGS Grant no.81); the NERC/BAS science programmes CACHE-PEP: Natural climate variability - extending the Americas palaeoclimate transect through the Antarctic Peninsula to the pole and GRADES-QWAD: Quaternary West Antarctic Deglaciations.

Snow and ice samples were taken from Moutonnee, Ablation and Citadel Bastion lakes on Alexander Island. Isotopic analyses of Oxygen, Carbon and Deuterium were conducted on the samples.

The dataset contains chronological and biomarker compound and brGDGT (branched Glyceryl Dialkyl Glyceryl Tetraether) mean summer temperature (MSAT) data for the last c. 6,000 years from sediments extracted from Fan Lake on Annenkov Island (near South Georgia) and Yanou Lake, King George Island, South Shetland Islands. Temperature was reconstructed using the Pearson et al. (2011) global calibration and the Foster et al. (2016) Antarctic calibration. For the latter, we studied 32 lakes from Antarctica, the sub-Antarctic Islands and Southern Chile to: 1) quantify their GDGT composition and investigate the environmental controls on GDGT composition; and 2) develop a GDGT-temperature calibration model for inferring past temperatures from Antarctic and sub-Antarctic lakes. The downcore temperature reconstruction data produced using the new Antarctic brGDGT-temperature calibration were tested on Fan Lake and Yanou Lake to provide a proof of concept for the new calibration model in the Southern Hemisphere. This study is an output of the British Antarctic Survey (BAS) Natural Environment Research Council (NERC) funded Science Program, and was funded by NERC Studentship NE/J500173/1 to LF (BAS and Newcastle University) with additional support from: the European Commission under the 7th Framework Programme through the Action - IMCONet (FP7 IRSES, action No.319718 and the ESF-funded IMCOAST project AP6 to SJR, both coordinated by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Germany). Additional funding from the Natural Environmental Research Council (NERC-CASS), and the German Research Foundation (DFG project no. BR 775/25-1). Logistic support from the NERC-British Antarctic Survey (BAS), HMS Endurance and 892 Naval Air Squadron, the Alfred Wegner Institute (AWI) and the Instituto Antartico Argentino (IAA).

Sediment cores were collected from the 3 sites (approx. 6m from Moutonnee Valley, 2.5m from Ablation Valley and 5m from Citadel Bastion on Alexander Island). They were analysed for physical property data including: magnetic susceptibility, wet weight, loss on ignition, grain size, isotopic content, bulk carbon, CHN, diatom content, forams, Authigenic carbonate, radiocarbon ages, Strontium and Neodymium content, major, trace and rare earth elements of sediments and clasts and clast lithological analysis. Analyses were carried out at Durham and Edinburgh with isotopic analysis conducted at NIGL (NERC Isotopic Geoscience Laboratory).

The general reference data consists of soil, rock and biological samples. These were analysed for grain size, CHN and carbon isotopes.