Roberts, S., Pearson, E., Gabriel, I., Blockley, S., Foster, L.(2023). Reconstructed temperature and tephra deposit age data from Yanou Lake, Fildes Peninsula, South Shetland Islands, northern Antarctic Peninsula.

(Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/621cf434-1517-4b36-887d-4285315af695

Methodology:

Glycerol dialkyl glycerol tetraether (GDGT) analysis of freshwater-brackish sediments from Yanou Lake dating to c. 6 ka was used to reconstruct mean summer air temperature (MSAT) and MSAT anomaly profiles (relative to the pre-industrial mean 1-0.25 cal. ka BP; RMSE = 2.45 degrees C; Pearson et al., 2011; Foster et al., 2016; Roberts et al., 2017). The published GDGT palaeotemperature reconstructions for Yanou Lake in Roberts et al. (2017) overestimated MSAT for data older than 2000 years due to a lack of data at the upper end of the Foster et al. (2016) Antarctic calibration dataset. Therefore, we constructed a new MSAT anomaly profile by combining GDGT-MSAT data from the global (Pearson et al., 2011) and Antarctic (Foster et al., 2016) GDGT calibration datasets and applied a new regression model based on the same compounds used in both (Juggins pers. comm). This produced a revised mean MSAT anomaly of 0.06 +/- 1.50 degrees C for the last 6,000 years of the Yanou Lake record, which is of a similar magnitude to the James Ross Island ice core mean annual temperature anomaly of 0.01 plus/minus 0.35 degrees C in the same period.

Revised modelled ages for tephra deposits in the Yanou Lake record were produced using 2020 calibration curves and Bayesian age-depth modelling in BACON v. 2.5 in R (Blaauw and Christen, 2011).

Data quality:

RMSE = 2.45±1.44 °C and 1.74±1.44 °C for global calibration temperature reconstructions and Antarctic/revised global+Antarctic calibration temperature reconstructions