Terrigenous Grain-Size Record of the Newfoundland Ridge Contourite Drift, IODP Site U1411: The First Physical Proxy Record of North Atlantic Abyssal Current Intensity during the Eocene-Oligocene Transition
Atlantic Meridional Overturning Circulation (AMOC) is a vital process that transfers heat and nutrients throughout the world's oceans, helping to regulate global climate and support marine ecosystems. The timing and nature of the shift to modern AMOC, and especially to deep-water formation in t...
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ftvirginiatec:oai:vtechworks.lib.vt.edu:10919/83539 2024-05-19T07:30:58+00:00 Terrigenous Grain-Size Record of the Newfoundland Ridge Contourite Drift, IODP Site U1411: The First Physical Proxy Record of North Atlantic Abyssal Current Intensity during the Eocene-Oligocene Transition Chilton, Kristin Danielle Geosciences Romans, Brian W. Eriksson, Kenneth A. Gill, Benjamin C. 2016-12-20 ETD application/pdf http://hdl.handle.net/10919/83539 unknown Virginia Tech vt_gsexam:9146 http://hdl.handle.net/10919/83539 In Copyright http://rightsstatements.org/vocab/InC/1.0/ Paleoceanography grain size analysis sortable silt Eocene-Oligocene Transition North Atlantic deep circulation Thesis 2016 ftvirginiatec 2024-05-01T01:21:07Z Atlantic Meridional Overturning Circulation (AMOC) is a vital process that transfers heat and nutrients throughout the world's oceans, helping to regulate global climate and support marine ecosystems. The timing and nature of the shift to modern AMOC, and especially to deep-water formation in the North Atlantic, has been a topic of ongoing study, with the Eocene-Oligocene Transition (EOT, ~34 Ma) as a potential focal point of this shift. However, the role played by abrupt EOT cooling and Antarctic glaciation in North Atlantic circulation remains unclear. Improved constraints on Paleogene circulation will provide insight into the sensitivity of AMOC to perturbations in global climate, which is particularly relevant in light of contemporary climate change. To examine deep North Atlantic circulation response to the EOT we obtained grain-size data from the terrigenous fraction of the mud-dominated sediments of the Southeast Newfoundland Ridge contourite drift complex at IODP Site U1411, which is interpreted to have formed under the influence of the Deep Western Boundary Current. We analyzed 195 samples that span 150 m of stratigraphy from 36-26 Ma. The main objective was to use the 'sortable silt' fraction (10-63 m) to generate a record of relative change in bottom-current intensity. These data are complemented with a record of the abundance and size of lithogenic sand (>63 m). Here we present the first physical proxy record of abyssal current intensity in the North Atlantic, from late Eocene to mid Oligocene. Invigoration of North Atlantic deep circulation occurred gradually (over Myr timescales), with no significant changes linked temporally to the EOT. We infer that deep circulation in the North Atlantic was not sensitive to the abrupt global cooling and Antarctic glaciation associated with the EOT. Rather, our data suggest that changes in North Atlantic circulation were likely governed by longer-term processes related to the opening of key tectonic gateways, such as the Greenland-Scotland Ridge in the North ... Thesis Antarc* Antarctic Greenland Greenland-Scotland Ridge Newfoundland North Atlantic VTechWorks (VirginiaTech) |
institution |
Open Polar |
collection |
VTechWorks (VirginiaTech) |
op_collection_id |
ftvirginiatec |
language |
unknown |
topic |
Paleoceanography grain size analysis sortable silt Eocene-Oligocene Transition North Atlantic deep circulation |
spellingShingle |
Paleoceanography grain size analysis sortable silt Eocene-Oligocene Transition North Atlantic deep circulation Chilton, Kristin Danielle Terrigenous Grain-Size Record of the Newfoundland Ridge Contourite Drift, IODP Site U1411: The First Physical Proxy Record of North Atlantic Abyssal Current Intensity during the Eocene-Oligocene Transition |
topic_facet |
Paleoceanography grain size analysis sortable silt Eocene-Oligocene Transition North Atlantic deep circulation |
description |
Atlantic Meridional Overturning Circulation (AMOC) is a vital process that transfers heat and nutrients throughout the world's oceans, helping to regulate global climate and support marine ecosystems. The timing and nature of the shift to modern AMOC, and especially to deep-water formation in the North Atlantic, has been a topic of ongoing study, with the Eocene-Oligocene Transition (EOT, ~34 Ma) as a potential focal point of this shift. However, the role played by abrupt EOT cooling and Antarctic glaciation in North Atlantic circulation remains unclear. Improved constraints on Paleogene circulation will provide insight into the sensitivity of AMOC to perturbations in global climate, which is particularly relevant in light of contemporary climate change. To examine deep North Atlantic circulation response to the EOT we obtained grain-size data from the terrigenous fraction of the mud-dominated sediments of the Southeast Newfoundland Ridge contourite drift complex at IODP Site U1411, which is interpreted to have formed under the influence of the Deep Western Boundary Current. We analyzed 195 samples that span 150 m of stratigraphy from 36-26 Ma. The main objective was to use the 'sortable silt' fraction (10-63 m) to generate a record of relative change in bottom-current intensity. These data are complemented with a record of the abundance and size of lithogenic sand (>63 m). Here we present the first physical proxy record of abyssal current intensity in the North Atlantic, from late Eocene to mid Oligocene. Invigoration of North Atlantic deep circulation occurred gradually (over Myr timescales), with no significant changes linked temporally to the EOT. We infer that deep circulation in the North Atlantic was not sensitive to the abrupt global cooling and Antarctic glaciation associated with the EOT. Rather, our data suggest that changes in North Atlantic circulation were likely governed by longer-term processes related to the opening of key tectonic gateways, such as the Greenland-Scotland Ridge in the North ... |
author2 |
Geosciences Romans, Brian W. Eriksson, Kenneth A. Gill, Benjamin C. |
format |
Thesis |
author |
Chilton, Kristin Danielle |
author_facet |
Chilton, Kristin Danielle |
author_sort |
Chilton, Kristin Danielle |
title |
Terrigenous Grain-Size Record of the Newfoundland Ridge Contourite Drift, IODP Site U1411: The First Physical Proxy Record of North Atlantic Abyssal Current Intensity during the Eocene-Oligocene Transition |
title_short |
Terrigenous Grain-Size Record of the Newfoundland Ridge Contourite Drift, IODP Site U1411: The First Physical Proxy Record of North Atlantic Abyssal Current Intensity during the Eocene-Oligocene Transition |
title_full |
Terrigenous Grain-Size Record of the Newfoundland Ridge Contourite Drift, IODP Site U1411: The First Physical Proxy Record of North Atlantic Abyssal Current Intensity during the Eocene-Oligocene Transition |
title_fullStr |
Terrigenous Grain-Size Record of the Newfoundland Ridge Contourite Drift, IODP Site U1411: The First Physical Proxy Record of North Atlantic Abyssal Current Intensity during the Eocene-Oligocene Transition |
title_full_unstemmed |
Terrigenous Grain-Size Record of the Newfoundland Ridge Contourite Drift, IODP Site U1411: The First Physical Proxy Record of North Atlantic Abyssal Current Intensity during the Eocene-Oligocene Transition |
title_sort |
terrigenous grain-size record of the newfoundland ridge contourite drift, iodp site u1411: the first physical proxy record of north atlantic abyssal current intensity during the eocene-oligocene transition |
publisher |
Virginia Tech |
publishDate |
2016 |
url |
http://hdl.handle.net/10919/83539 |
genre |
Antarc* Antarctic Greenland Greenland-Scotland Ridge Newfoundland North Atlantic |
genre_facet |
Antarc* Antarctic Greenland Greenland-Scotland Ridge Newfoundland North Atlantic |
op_relation |
vt_gsexam:9146 http://hdl.handle.net/10919/83539 |
op_rights |
In Copyright http://rightsstatements.org/vocab/InC/1.0/ |
_version_ |
1799468820378681344 |