Isotopic signature of massive, buried ice in eastern Taylor Valley, Antarctica: Implications for its origin

The coastal regions of the McMurdo Dry Valleys, Antarctica, contain deposits of the Ross Sea Drift, sedimentary material left from the Ross Sea ice sheet from the advance of the West Antarctic ice sheet during the Last Glacial Maximum. Much of this deposit is ice-cored, but data on the stable isotopic composition of water from this ice, which may contain a valuable climate archive, are sparse or incomplete. Widespread thermokarstic ground subsidence in this coastal thaw zone of the McMurdo Dry Valleys suggests that these potential records are rapidly being lost due to the melting of ground ice and permafrost. We collected samples of massive buried ice from the Ross Sea Drift in eastern Taylor Valley for delta O-18-H2O and delta H-2-H2O and measured a broad range of values (delta O-18 = -27.7 to -37.3 parts per thousand; delta H-2 = -210 to -295 parts per thousand). These buried ice deposits do not show evidence of alteration through sublimation or evaporation, plot along the local meteoric water line, and have values that indicate ice deposition under a colder climate than present conditions. We propose that this ice was sourced from the Ross Sea ice sheet during the Last Glacial Maximum and contains a valuable and accessible climate record.

Automated summary

The coastal regions of the McMurdo Dry Valleys in Antarctica contain deposits of the Ross Sea Drift, which were left by the Ross Sea ice sheet during the Last Glacial Maximum. Analysis of buried ice samples from this deposit suggests that they formed in a colder climate than the present conditions.