ALBERT

Description: This dataset of radio-echo sounding internal reflecting horizons (IRH) which were traced across the radar surveys conducted in the 2019/20 Antarctic summer season at Little Come C, in the Dome C region of the East Antarctic Plateau. The data set is associated to publication: Chung, A., et al. (2023). The data were collected during a radar survey conducted in the Antarctic field seasons of 2019-20 using the Little Dome C - Very High Frequency (LDC-VHF) multichannel coherent radar depth sounder developed through a collaboration of The University of Alabama (UA), the University of Copenhagen (CPH) and the Alfred Wegener Institute (AWI). The survey covered Patches A and B of Little Dome C (Lilien et al., 2021), in order to select the exact drill site for the Beyond EPICA Oldest Ice drilling project. The datasets consists of 12 transects systematically covering Patches A and B with parallel lines, over an area of approximately 5×8 km^2. The dataset contains 19 IRHs, the basal unit horizon and the ice-bed interface which were manually traced by Ailsa Chung, using the seismic environment of the Echos software from Paradigm Geophysical. A single file for each IRH is provided in a text file, tab separated format with both depth and two-way travel time. The conversion to depth done using c = 0.1685 m/μs and firn correction of 10 m. The IRHs are provided at approximately 3.5 m spacial resolution.

Description: The data here described are presented in the submitted paper Response of the Wilkes Subglacial Basin Ice Sheet to Southern Ocean Warming During Late Pleistocene Interglacials by Crotti et al. This data set includes new high resolution measurements of d-excess, d18O and ssNa+ for the Antarctic TALDICE ice core (Latitude: -72.783330, Longitude: 159.066670, Elevation: 2315.0 m). The new data set covers the interglacials periods of MIS 5.5, MIS 7.5 and MIS 9.3 (1486 m depth - 1548 m depth). The data are drawn on the TALDICE deep1 chronology (Crotti et al. 2021). The d-excess (d = δD − 8 × δ18O) (permill) record covers the periods MIS 5.5 , MIS 7.5 and 9.3 MIS is at 5 cm resolution and spans the following age-depths intervals: • MIS 5.5. Between 1378.5 and 1421.65 m depth, 110-135 ka • MIS 7.5. Between 1521.85 and 1524.5 m depth, 243-248 ka • MIS 9.3. Between 1541.80 and 1547.90 m depth, 320-343 ka The d18O record (permill) covers the periods MIS 5.5 , MIS 7.5 and 9.3 MIS is at 5 cm resolution and spans the following age-depths intervals: • MIS 7.5. Between 1521.85 and 1524.5 m depth, 243-248 ka • MIS 9.3. Between 1541.80 and 1547.90 m depth, 320-343 ka The ssNa+ fluxes record covers the periods MIS 5.5 , MIS 7.5 and 9.3 MIS is at 8 cm resolution and pans the following age-depths intervals: • MIS 7.5. Between 1521.81 and 1524.54 m depth, 243-248 ka • MIS 9.3. Between 1541.73 and 1547.96 m depth, 320-343 ka The d18O and dD (non presented here) to calculate the d-excess were analysed in Italy (University of Venice) and France (LSCE) using the Cavity Ring Down Spectroscopy (CRDS) technique. Analyses were performed using a Picarro isotope water analyser (L2130-i version for both laboratories). The data were calibrated using a three-point linear calibration with three lab-standards that were themselves calibrated versus Standard Mean Ocean Water (SMOW). The average precision for the δ18O and δD measurements is 0.1 and 0.7 ‰, respectively. The concentrations of ssNa+ were measured on TALDICE ice samples at 8 cm resolution by classical ion chromatography on discrete samples collected using a melting device connected to an auto-sampler for the MIS 7.5 and MIS 9.3 whereas Continuous Flow Analysis (CFA) was applied for MIS 5.5 samples. The total deposition ssNa+ flux was calculated multiplying the measured ice concentration of ssNa+ by the reconstructed accumulation rate. The accumulation rates were derived from the accumulation rates were obtained from the TALDICE deep1 age scale (Crotti et al. 2021).

Description: The data here described are presented in the submitted paper Response of the Wilkes Subglacial Basin Ice Sheet to Southern Ocean Warming During Late Pleistocene Interglacials by Crotti et al. This data set includes new high resolution measurements of d-excess, d18O and ssNa+ for the Antarctic TALDICE ice core (Latitude: -72.783330, Longitude: 159.066670, Elevation: 2315.0 m). The new data set covers the interglacials periods of MIS 5.5, MIS 7.5 and MIS 9.3 (1486 m depth - 1548 m depth). The data are drawn on the TALDICE deep1 chronology (Crotti et al. 2021). The d-excess (d = δD − 8 × δ18O) (permill) record covers the periods MIS 5.5 , MIS 7.5 and 9.3 MIS is at 5 cm resolution and spans the following age-depths intervals: • MIS 5.5. Between 1378.5 and 1421.65 m depth, 110-135 ka • MIS 7.5. Between 1521.85 and 1524.5 m depth, 243-248 ka • MIS 9.3. Between 1541.80 and 1547.90 m depth, 320-343 ka The d18O record (permill) covers the periods MIS 5.5 , MIS 7.5 and 9.3 MIS is at 5 cm resolution and spans the following age-depths intervals: • MIS 7.5. Between 1521.85 and 1524.5 m depth, 243-248 ka • MIS 9.3. Between 1541.80 and 1547.90 m depth, 320-343 ka The ssNa+ fluxes record covers the periods MIS 5.5 , MIS 7.5 and 9.3 MIS is at 8 cm resolution and pans the following age-depths intervals: • MIS 7.5. Between 1521.81 and 1524.54 m depth, 243-248 ka • MIS 9.3. Between 1541.73 and 1547.96 m depth, 320-343 ka The d18O and dD (non presented here) to calculate the d-excess were analysed in Italy (University of Venice) and France (LSCE) using the Cavity Ring Down Spectroscopy (CRDS) technique. Analyses were performed using a Picarro isotope water analyser (L2130-i version for both laboratories). The data were calibrated using a three-point linear calibration with three lab-standards that were themselves calibrated versus Standard Mean Ocean Water (SMOW). The average precision for the δ18O and δD measurements is 0.1 and 0.7 ‰, respectively. The concentrations of ssNa+ were measured on TALDICE ice samples at 8 cm resolution by classical ion chromatography on discrete samples collected using a melting device connected to an auto-sampler for the MIS 7.5 and MIS 9.3 whereas Continuous Flow Analysis (CFA) was applied for MIS 5.5 samples. The total deposition ssNa+ flux was calculated multiplying the measured ice concentration of ssNa+ by the reconstructed accumulation rate. The accumulation rates were derived from the accumulation rates were obtained from the TALDICE deep1 age scale (Crotti et al. 2021).