Refining Interpretations of a Deglacial Record in Gulf of Mexico Marine Sediment Cores
Abstract
Originally cored by the USGS for gas hydrate investigations, 3 cores from the IMAGES VIII/PAGE 127 expedition have been repurposed for undergraduate course-based paleoclimate research at JMU. The upper 14 sections of cores MD02-2535, MD02-2555, and MD02-2560 are stratigraphic records of climate and provenance variations that influenced sediment deposition in the Gulf of Mexico during the Pleistocene and Holocene. Shipboard interpretations of the color reflectance data for these cores suggested that two dark stratigraphic intervals present in all of the cores marked the Last Glacial Maximum (LGM), ~18-24 ka, and the Younger Dryas (YD) cooling event, ~12.9-11.6 ka (Bout-Roumazeilles and Trentesaux, 2007). However, results from more recent investigations of each core were inconsistent with the shipboard interpretation. Based on sediment composition, grain size, C-14 dates and calculated sedimentation rates, JMU students re-interpreted the main dark interval as meltwater pulse 1A instead of the LGM and the smaller dark interval above it as meltwater pulse 1B instead of the YD (Melander et al., 2017; Richardson et al., 2018; Nebel et al., 2019). The objectives of the current research are to synthesize the previous findings and to further improve the age models with additional C-14 dates in order to refine our understanding of the deglaciation recorded in these three Gulf of Mexico cores. Differences among the cores may be attributed to their different geographic placements, such as volume of sediment input or sediment source(s). Specifically, core MD02-2535 is the farthest from the Mississippi River, ~315 km, and it may have been influenced by other nearby drainage systems. Overall, this research recounts the deglaciation of the Laurentide Ice Sheet using the hypothesis that meltwater pulses 1A and 1B, and the YD event are represented in these cores.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP23C1675M
- Keywords:
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- 3099 General or miscellaneous;
- MARINE GEOLOGY AND GEOPHYSICS;
- 4299 General or miscellaneous;
- OCEANOGRAPHY: GENERAL;
- 4999 General or miscellaneous;
- PALEOCEANOGRAPHY