Sea-level history of the Gulf of Mexico since the Last Glacial Maximum with implications for the melting history of the Laurentide Ice Sheet |
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| Institution: | 1. Department of Earth Science, University of California, Santa Barbara, 1006 Webb Hall, Santa Barbara, CA 93106, USA;2. Department of Earth Sciences, Rice University, 6100 S. Main, MS-126, Houston, TX, 77005 USA;3. Department of Physics, East Carolina University, C-209 Howell Science Complex, 10th Street, Greenville, NC 27858, USA;4. Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia;1. Department of Geosciences, University of Rhode Island, Woodward Hall, 9 East Alumni Avenue, Kingston, RI, 02881, USA;2. Sea Level Research, Department of Earth and Environmental Science, University of Pennsylvania, Hayden Hall, 240 South 33rd St, Philadelphia, PA, 19104, USA;3. Sea Level Research, Institute of Marine and Coastal Sciences, School of Environmental and Biological Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901, USA;4. British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham, NG12 5GG, UK;5. Geologic Hazards Science Center, US Geological Survey, 1711 Illinois St., Golden, CO 80401, USA;6. Alaska Science Center, US Geological Survey, 4200 University Drive, Anchorage, AK 99508, USA;7. Nicholas School of the Environment, Duke University, Box 90328, Durham, NC 27708, USA;8. Department of Geography and Geology, University of North Carolina Wilmington, Wilmington, NC 28403, USA;1. Centre for Past Climate Studies, Department of Geoscience and Arctic Research Centre, Aarhus University, Aarhus, Denmark;2. Geological Survey of Denmark and Greenland (GEUS), Copenhagen, Denmark;1. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA;2. Laboratoire des Sciences du Climat et de l''Environnement, L''Orme des Merisiers, CEA Saclay, 91 191 Gif sur Yvette, France;3. UMR 8148, GEOPS, Université Paris Sud, CNRS, 91405 Orsay Cedex, France |
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| Abstract: | Sea-level records from the Gulf of Mexico at the Last Glacial Maximum, 20 ka, are up to 35 m higher than time-equivalent sea-level records from equatorial regions. The most popular hypothesis for explaining this disparity has been uplift due to the forebulge created by loading from Mississippi River sediments. Using over 50 new radiocarbon dates as well as existing published data obtained from shallow-marine deposits within the northern Gulf of Mexico and numerical models simulating the impact of loading due to the Mississippi Fan and glacio-hydro-isostasy, we test several possible explanations for this sea-level disparity. We find that neither a large radiocarbon reservoir, sedimentary loading due to the Mississippi Fan, nor large-scale regional uplift can explain this disparity. We do find that with an appropriate model for the Laurentide Ice Sheet, the observations from the Gulf of Mexico can be explained by the process of glacio-hydro-isostasy. Our analysis suggests that in order to explain this disparity one must consider a Laurentide Ice Sheet reconstruction with less ice from 15 ka to its disappearance 6 ka and more ice from the Last Glacial Maximum to 15 ka than some earlier models have suggested. This supports a Laurentide contribution to meltwater pulse 1-A, which could not have come entirely from its southern sector. |
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