Pliocene-Pleistocene evolution of the Laurentide Ice Sheet and North Atlantic ocean circulation
The high sensitivity of the North Atlantic to climate change makes it an ideal region to study in palaeoclimate research to understand better the workings our planet’s climate system. To this end, this thesis reports new authigenic lead (Pb) isotope and fish debris neodymium (Nd isotope; Nd) record...
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University of Exeter
2022
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ftunivexeter:oai:ore.exeter.ac.uk:10871/129984 2024-09-15T17:46:33+00:00 Pliocene-Pleistocene evolution of the Laurentide Ice Sheet and North Atlantic ocean circulation Parker, R Bailey, Ian Littler, Kate 2022 http://hdl.handle.net/10871/129984 unknown University of Exeter Camborne School of Mines https://doi.org/10.24378/exe.4065 http://hdl.handle.net/10871/129984 2023-12-31 Thesis chapters are still being published http://www.rioxx.net/licenses/all-rights-reserved Palaeoclimate Radiogenic isotopes North Atlantic Continental weathering Laurentide Ice Sheet Ocean circulation Quaternary Last Glacial Cycle Thesis or dissertation PhD in Geology Doctoral Doctoral Thesis 2022 ftunivexeter https://doi.org/10.24378/exe.4065 2024-07-03T14:16:46Z The high sensitivity of the North Atlantic to climate change makes it an ideal region to study in palaeoclimate research to understand better the workings our planet’s climate system. To this end, this thesis reports new authigenic lead (Pb) isotope and fish debris neodymium (Nd isotope; Nd) records from northwest North Atlantic IODP sites U1302/3 (~50˚N) and IODP Site U1313 (~41˚N), which are used to investigate the evolution of the North American Laurentide Ice Sheet (LIS) and North Atlantic ocean circulation during the Plio-Pleistocene. Authigenic Pb isotope records from sites U1302/3 track chemical weathering on North America, which varies as a function of LIS extent. In Chapters 3 and 4, data of this sort spanning the past ~500 kyr are used to demonstrate that the timescale of LIS retreat during each of the largest three glacial terminations of the mid- to late-Pleistocene – Terminations (T) 5 (~424 ka), T2 (~130 ka) and T1 (~14 ka) – is different; a fact that should be taken into consideration when using models of glacio-isostatic adjustment to correct estimates of sea-level highstand during interglacial marine isotope stages (MIS) 11 (~410 ka) and 5e (~124 ka), which are widely considered to represent the most recent geological analogues for near-future changes in Earth’s climate. The early timing inferred in Chapter 4 for LIS (and Greenland Ice Sheet) break-up during T5 (by ~ 418 ka) also makes it likely that the sea-level highstand associated with MIS 11 (by ~405 ka) reflects ice loss from Antarctica, and thus lies in the upper end of estimates (~+1–13 m above present). In Chapter 5, a new Nd record from Site U1313 is used to track the evolution of the end-member composition of Northern Sourced Waters bathing the deep North Atlantic during the Last Glacial Cycle (~124–0 ka). The history of high-latitude changes in climate inferred here to be responsible for this evolution is applied to older Nd records from this region to infer climate changes in the high northern latitude during the last two major ... Doctoral or Postdoctoral Thesis Antarc* Antarctica Greenland Ice Sheet North Atlantic University of Exeter: Open Research Exeter (ORE) |
institution |
Open Polar |
collection |
University of Exeter: Open Research Exeter (ORE) |
op_collection_id |
ftunivexeter |
language |
unknown |
topic |
Palaeoclimate Radiogenic isotopes North Atlantic Continental weathering Laurentide Ice Sheet Ocean circulation Quaternary Last Glacial Cycle |
spellingShingle |
Palaeoclimate Radiogenic isotopes North Atlantic Continental weathering Laurentide Ice Sheet Ocean circulation Quaternary Last Glacial Cycle Parker, R Pliocene-Pleistocene evolution of the Laurentide Ice Sheet and North Atlantic ocean circulation |
topic_facet |
Palaeoclimate Radiogenic isotopes North Atlantic Continental weathering Laurentide Ice Sheet Ocean circulation Quaternary Last Glacial Cycle |
description |
The high sensitivity of the North Atlantic to climate change makes it an ideal region to study in palaeoclimate research to understand better the workings our planet’s climate system. To this end, this thesis reports new authigenic lead (Pb) isotope and fish debris neodymium (Nd isotope; Nd) records from northwest North Atlantic IODP sites U1302/3 (~50˚N) and IODP Site U1313 (~41˚N), which are used to investigate the evolution of the North American Laurentide Ice Sheet (LIS) and North Atlantic ocean circulation during the Plio-Pleistocene. Authigenic Pb isotope records from sites U1302/3 track chemical weathering on North America, which varies as a function of LIS extent. In Chapters 3 and 4, data of this sort spanning the past ~500 kyr are used to demonstrate that the timescale of LIS retreat during each of the largest three glacial terminations of the mid- to late-Pleistocene – Terminations (T) 5 (~424 ka), T2 (~130 ka) and T1 (~14 ka) – is different; a fact that should be taken into consideration when using models of glacio-isostatic adjustment to correct estimates of sea-level highstand during interglacial marine isotope stages (MIS) 11 (~410 ka) and 5e (~124 ka), which are widely considered to represent the most recent geological analogues for near-future changes in Earth’s climate. The early timing inferred in Chapter 4 for LIS (and Greenland Ice Sheet) break-up during T5 (by ~ 418 ka) also makes it likely that the sea-level highstand associated with MIS 11 (by ~405 ka) reflects ice loss from Antarctica, and thus lies in the upper end of estimates (~+1–13 m above present). In Chapter 5, a new Nd record from Site U1313 is used to track the evolution of the end-member composition of Northern Sourced Waters bathing the deep North Atlantic during the Last Glacial Cycle (~124–0 ka). The history of high-latitude changes in climate inferred here to be responsible for this evolution is applied to older Nd records from this region to infer climate changes in the high northern latitude during the last two major ... |
author2 |
Bailey, Ian Littler, Kate |
format |
Doctoral or Postdoctoral Thesis |
author |
Parker, R |
author_facet |
Parker, R |
author_sort |
Parker, R |
title |
Pliocene-Pleistocene evolution of the Laurentide Ice Sheet and North Atlantic ocean circulation |
title_short |
Pliocene-Pleistocene evolution of the Laurentide Ice Sheet and North Atlantic ocean circulation |
title_full |
Pliocene-Pleistocene evolution of the Laurentide Ice Sheet and North Atlantic ocean circulation |
title_fullStr |
Pliocene-Pleistocene evolution of the Laurentide Ice Sheet and North Atlantic ocean circulation |
title_full_unstemmed |
Pliocene-Pleistocene evolution of the Laurentide Ice Sheet and North Atlantic ocean circulation |
title_sort |
pliocene-pleistocene evolution of the laurentide ice sheet and north atlantic ocean circulation |
publisher |
University of Exeter |
publishDate |
2022 |
url |
http://hdl.handle.net/10871/129984 |
genre |
Antarc* Antarctica Greenland Ice Sheet North Atlantic |
genre_facet |
Antarc* Antarctica Greenland Ice Sheet North Atlantic |
op_relation |
https://doi.org/10.24378/exe.4065 http://hdl.handle.net/10871/129984 |
op_rights |
2023-12-31 Thesis chapters are still being published http://www.rioxx.net/licenses/all-rights-reserved |
op_doi |
https://doi.org/10.24378/exe.4065 |
_version_ |
1810494782251728896 |