Laurentide Ice-Sheet Meltwater Sources to the Gulf of Mexico During the Last Deglaciation: Assessing Data Reconstructions Using Water Isotope Enabled Simulations
Abstract
Sediment cores from the Gulf of Mexico show evidence of meltwater derived from the Laurentide Ice Sheet during the last deglaciation. Recent studies using geochemical measurements of individual foraminifera suggest changes in the oxygen isotopic composition of the meltwater as deglaciation proceeded. Here we use the water isotope enabled climate model simulations (NASA GISS ModelE-R) to investigate potential sources of meltwater within the ice sheet. We find that initial melting of the ice sheet from the southern margin contributed an oxygen isotope value reflecting a low-elevation, local precipitation source. As deglacial melting proceeded, meltwater delivered to the Gulf of Mexico had a more negative oxygen isotopic value, which the climate model simulates as being sourced from the high-elevation, high-latitude interior of the ice sheet. This study demonstrates the utility of combining stable isotope analyses with climate model simulations to investigate past changes in the hydrologic cycle.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMPP21D..07V
- Keywords:
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- 0424 Biosignatures and proxies;
- BIOGEOSCIENCES;
- 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCES;
- 1622 Earth system modeling;
- GLOBAL CHANGE;
- 4950 Paleoecology;
- PALEOCEANOGRAPHY