Abrupt climate change during the last glacial period: A Gulf of Mexico perspective
Understanding the cause of abrupt climate change in the geologic past can help assess the potential magnitude and variability of future changes in regional and global climate. The research presented here focuses on some of the first records of hydrologic variability in the central North American con...
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ftusouthflorida:oai:digitalcommons.usf.edu:etd-3557 2023-07-30T03:57:32+02:00 Abrupt climate change during the last glacial period: A Gulf of Mexico perspective Hill, Heather W 2006-06-01T07:00:00Z application/pdf https://digitalcommons.usf.edu/etd/2558 https://digitalcommons.usf.edu/context/etd/article/3557/viewcontent/SFE0001539.pdf unknown Digital Commons @ University of South Florida https://digitalcommons.usf.edu/etd/2558 https://digitalcommons.usf.edu/context/etd/article/3557/viewcontent/SFE0001539.pdf default USF Tampa Graduate Theses and Dissertations Marine isotope stage 3 Laurentide ice sheet meltwater Mississippi river Floods Ocean-continent interactions American Studies Arts and Humanities dissertation 2006 ftusouthflorida 2023-07-13T21:36:15Z Understanding the cause of abrupt climate change in the geologic past can help assess the potential magnitude and variability of future changes in regional and global climate. The research presented here focuses on some of the first records of hydrologic variability in the central North American continent during an interval of Marine Isotope Stage 3 (24-57 thousand years before present (ka)). Sediment core MD02-2551 from the Orca Basin, northern Gulf of Mexico, is used to document the first detailed melting history of the southern margin of the Laurentide Ice Sheet (LIS) during MIS 3, and to record terrestrial inputs from the Mississippi River related to changes in evaporation-precipitation over the mid-continent, from 28-45 ka.Paired measurements of oxygen isotopes and Mg/Ca-SST on the planktonic foraminifera Globigerinoides ruber (pink) are used to calculate the oxygen isotopic composition of seawater and test one of the key hypotheses for abrupt climate change. Five rvals of freshwater input from 28-45 ka do not match the abrupt Dansgaard-Oeschger temperature oscillations recorded in Greenland ice. Rather, summer melting of the LIS may have occurred during Antarctic warming and likely contributed to sea-level variability during MIS 3. A detailed assessment over one of the meltwater events, using the oxygen and carbon isotopic composition of G. ruber and the deeper dwelling Neogloboquadrina dutertrei, demonstrate that meltwater was confined to the surface layers and likely had an impact on the biological pump in the Gulf of Mexico. A similar oxygen isotopic composition of seawater record determined from the year-round white G. ruber suggests that melting was not limited to the warmest summer months. The timing of LIS meltwater input is decoupled from an interval of enhanced wet conditions over the North American continent and increased Mississippi River discharge, as shown by a suite of organic and sedimentologic proxies. Increasing summer insolation on the orbital scale may have led to a northward migration ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Greenland Ice Sheet Orca Planktonic foraminifera University of South Florida St. Petersburg: Digital USFSP Antarctic Greenland |
institution |
Open Polar |
collection |
University of South Florida St. Petersburg: Digital USFSP |
op_collection_id |
ftusouthflorida |
language |
unknown |
topic |
Marine isotope stage 3 Laurentide ice sheet meltwater Mississippi river Floods Ocean-continent interactions American Studies Arts and Humanities |
spellingShingle |
Marine isotope stage 3 Laurentide ice sheet meltwater Mississippi river Floods Ocean-continent interactions American Studies Arts and Humanities Hill, Heather W Abrupt climate change during the last glacial period: A Gulf of Mexico perspective |
topic_facet |
Marine isotope stage 3 Laurentide ice sheet meltwater Mississippi river Floods Ocean-continent interactions American Studies Arts and Humanities |
description |
Understanding the cause of abrupt climate change in the geologic past can help assess the potential magnitude and variability of future changes in regional and global climate. The research presented here focuses on some of the first records of hydrologic variability in the central North American continent during an interval of Marine Isotope Stage 3 (24-57 thousand years before present (ka)). Sediment core MD02-2551 from the Orca Basin, northern Gulf of Mexico, is used to document the first detailed melting history of the southern margin of the Laurentide Ice Sheet (LIS) during MIS 3, and to record terrestrial inputs from the Mississippi River related to changes in evaporation-precipitation over the mid-continent, from 28-45 ka.Paired measurements of oxygen isotopes and Mg/Ca-SST on the planktonic foraminifera Globigerinoides ruber (pink) are used to calculate the oxygen isotopic composition of seawater and test one of the key hypotheses for abrupt climate change. Five rvals of freshwater input from 28-45 ka do not match the abrupt Dansgaard-Oeschger temperature oscillations recorded in Greenland ice. Rather, summer melting of the LIS may have occurred during Antarctic warming and likely contributed to sea-level variability during MIS 3. A detailed assessment over one of the meltwater events, using the oxygen and carbon isotopic composition of G. ruber and the deeper dwelling Neogloboquadrina dutertrei, demonstrate that meltwater was confined to the surface layers and likely had an impact on the biological pump in the Gulf of Mexico. A similar oxygen isotopic composition of seawater record determined from the year-round white G. ruber suggests that melting was not limited to the warmest summer months. The timing of LIS meltwater input is decoupled from an interval of enhanced wet conditions over the North American continent and increased Mississippi River discharge, as shown by a suite of organic and sedimentologic proxies. Increasing summer insolation on the orbital scale may have led to a northward migration ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Hill, Heather W |
author_facet |
Hill, Heather W |
author_sort |
Hill, Heather W |
title |
Abrupt climate change during the last glacial period: A Gulf of Mexico perspective |
title_short |
Abrupt climate change during the last glacial period: A Gulf of Mexico perspective |
title_full |
Abrupt climate change during the last glacial period: A Gulf of Mexico perspective |
title_fullStr |
Abrupt climate change during the last glacial period: A Gulf of Mexico perspective |
title_full_unstemmed |
Abrupt climate change during the last glacial period: A Gulf of Mexico perspective |
title_sort |
abrupt climate change during the last glacial period: a gulf of mexico perspective |
publisher |
Digital Commons @ University of South Florida |
publishDate |
2006 |
url |
https://digitalcommons.usf.edu/etd/2558 https://digitalcommons.usf.edu/context/etd/article/3557/viewcontent/SFE0001539.pdf |
geographic |
Antarctic Greenland |
geographic_facet |
Antarctic Greenland |
genre |
Antarc* Antarctic Greenland Ice Sheet Orca Planktonic foraminifera |
genre_facet |
Antarc* Antarctic Greenland Ice Sheet Orca Planktonic foraminifera |
op_source |
USF Tampa Graduate Theses and Dissertations |
op_relation |
https://digitalcommons.usf.edu/etd/2558 https://digitalcommons.usf.edu/context/etd/article/3557/viewcontent/SFE0001539.pdf |
op_rights |
default |
_version_ |
1772817956713005056 |