Late Pleistocene and Holocene glacier and climate change
This dissertation presents results from three studies that address major scientific questions in glacial geology and paleoclimatology for the late Pleistocene and Holocene using relatively new geochemical and statistical techniques. Each of the studies attempts to answer a longstanding question in t...
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ftoregonstate:ir.library.oregonstate.edu:3484zm26f 2024-09-15T18:12:17+00:00 Late Pleistocene and Holocene glacier and climate change Marcott, Shaun Andrew Clark, Peter Hostetler, Steven Stoner, Joseph Brook, Edward Geosciences Oregon State University. Graduate School https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/3484zm26f English [eng] eng unknown Oregon State University https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/3484zm26f All rights reserved Dissertation ftoregonstate 2024-07-22T18:06:06Z This dissertation presents results from three studies that address major scientific questions in glacial geology and paleoclimatology for the late Pleistocene and Holocene using relatively new geochemical and statistical techniques. Each of the studies attempts to answer a longstanding question in the respective field using geochemical or statistical methods that have not been applied to the problem thus far. A longstanding question in glaciology is the nature and mechanism of the so- called "Heinrich events" of the last ~60 ka. These massive iceberg discharge events into the North Atlantic from the partial breakup of the Laurentide Ice Sheet are identified from distinct ice rafted debris and detrital carbonate layers in marine sediment cores. The mechanism associated with the initiation of these events is commonly thought to be related to internal ice sheet instabilities. However, Heinrich events consistently occur following a long cooling trend that culminates in an extreme cold event, thus suggesting a possible triggering mechanism by climate. Recent modeling work has proposed an oceanic mechanism associated with ocean warming, but no physical evidence has been made available to date. To test this ocean-warming hypothesis, we measured temperature sensitive trace metals and stable isotopes in benthic foraminifera from a sediment core collected in the western North Atlantic that spans the last six Heinrich events and compared our results to climate model simulations using CCSM3. Our results show subsurface warming occurred prior to or coeval with nearly all of the Heinrich events of the last ~60 ka, thus implicating subsurface ocean warming as the main trigger of these rapid breakups of the Laurentide Ice Sheet. In the field of glacial geology a longstanding question has been the timing of alpine glacial advances during the Holocene. A number of studies have interpreted several Holocene glacial advances in western North America, but age control is based largely on relative dating techniques, which have been ... Doctoral or Postdoctoral Thesis Ice Sheet North Atlantic ScholarsArchive@OSU (Oregon State University) |
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ScholarsArchive@OSU (Oregon State University) |
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English unknown |
description |
This dissertation presents results from three studies that address major scientific questions in glacial geology and paleoclimatology for the late Pleistocene and Holocene using relatively new geochemical and statistical techniques. Each of the studies attempts to answer a longstanding question in the respective field using geochemical or statistical methods that have not been applied to the problem thus far. A longstanding question in glaciology is the nature and mechanism of the so- called "Heinrich events" of the last ~60 ka. These massive iceberg discharge events into the North Atlantic from the partial breakup of the Laurentide Ice Sheet are identified from distinct ice rafted debris and detrital carbonate layers in marine sediment cores. The mechanism associated with the initiation of these events is commonly thought to be related to internal ice sheet instabilities. However, Heinrich events consistently occur following a long cooling trend that culminates in an extreme cold event, thus suggesting a possible triggering mechanism by climate. Recent modeling work has proposed an oceanic mechanism associated with ocean warming, but no physical evidence has been made available to date. To test this ocean-warming hypothesis, we measured temperature sensitive trace metals and stable isotopes in benthic foraminifera from a sediment core collected in the western North Atlantic that spans the last six Heinrich events and compared our results to climate model simulations using CCSM3. Our results show subsurface warming occurred prior to or coeval with nearly all of the Heinrich events of the last ~60 ka, thus implicating subsurface ocean warming as the main trigger of these rapid breakups of the Laurentide Ice Sheet. In the field of glacial geology a longstanding question has been the timing of alpine glacial advances during the Holocene. A number of studies have interpreted several Holocene glacial advances in western North America, but age control is based largely on relative dating techniques, which have been ... |
author2 |
Clark, Peter Hostetler, Steven Stoner, Joseph Brook, Edward Geosciences Oregon State University. Graduate School |
format |
Doctoral or Postdoctoral Thesis |
author |
Marcott, Shaun Andrew |
spellingShingle |
Marcott, Shaun Andrew Late Pleistocene and Holocene glacier and climate change |
author_facet |
Marcott, Shaun Andrew |
author_sort |
Marcott, Shaun Andrew |
title |
Late Pleistocene and Holocene glacier and climate change |
title_short |
Late Pleistocene and Holocene glacier and climate change |
title_full |
Late Pleistocene and Holocene glacier and climate change |
title_fullStr |
Late Pleistocene and Holocene glacier and climate change |
title_full_unstemmed |
Late Pleistocene and Holocene glacier and climate change |
title_sort |
late pleistocene and holocene glacier and climate change |
publisher |
Oregon State University |
url |
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/3484zm26f |
genre |
Ice Sheet North Atlantic |
genre_facet |
Ice Sheet North Atlantic |
op_relation |
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/3484zm26f |
op_rights |
All rights reserved |
_version_ |
1810449878926491648 |