Subglacial precipitates record Antarctic ice sheet response to Southern
Ocean warming
- Jessica Gagliardi,
- Terrence Blackburn,
- Gavin Piccione,
- Slawek Tulaczyk,
- Brenhin Keller
Jessica Gagliardi
University of California, Santa Cruz
Corresponding Author:jgagliardi@ucsc.edu
Author ProfileAbstract
Subglacial calcite precipitation is thought to occur in East Antarctica
during periods when warm Southern Ocean waters access the ice sheet
margin. Here we present an expanded precipitate archive that includes a
continent-wide compilation of 40 new and previously reported calcite
U-Th ages with isotopic compositional data. These data are interpreted
to record periods when interior meltwaters are exported to the ice sheet
margins as a result of ice acceleration and thinning. An assessment of
coincidence between U-Th dates, ranging from 16-256 ka, and peaks in
Southern Ocean temperature yields a statistically significant
correlation. Additional comparison of precipitate dates and climate data
finds that calcite formation and ice acceleration cluster within periods
of enhanced millennial scale climate variability as well as high global
ice volume. This sensitivity to background climate is consistent with
the hypothesis that these factors exert some control on ice sheet
response to changes in climate.