Pliocene sea ice evolution in the Iceland and Labrador Sea – A biomarker approach
Sea ice plays a crucial role in the climate system. Although this is broadly acknowledged, the role of sea ice is not fully understood, especially during warmer periods such as the Pliocene (5.88–2.58 Million years (Ma) ago). Fragmentary evidence suggests that the Arctic sea ice was reduced in the P...
Published in: | Earth and Planetary Science Letters |
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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The University of Bergen
2017
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ftunivbergen:oai:bora.uib.no:1956/16992 2023-05-15T14:51:14+02:00 Pliocene sea ice evolution in the Iceland and Labrador Sea – A biomarker approach Clotten, Caroline 2017-12-07 application/pdf https://hdl.handle.net/1956/16992 eng eng The University of Bergen Paper I: Clotten, C., Stein, R., Fahl, K., Schreck, M., De Schepper, S. On the Causes of Sea Ice in the Early Pliocene Iceland Sea. Full text not available in BORA. Clotten, C., Stein, R., Fahl, K., De Schepper, S (2018). Seasonal sea ice cover during the warm Pliocene: evidence from the Iceland Sea (ODP Site 907). Earth and Planetary Science Letters. 481:61-72. The accepted version is available in the main thesis. The article is also available at: http://dx.doi.org/10.1016/j.epsl.2017.10.011 Paper III: Clotten, C., Stein, R., Fahl, K., De Schepper, S. Sea ice presence in the Labrador Sea prior to the Northern Hemisphere Glaciation. Full text not available in BORA. Paper IV: Schreck, M., Nam, S.-I., Clotten, C., Fahl, K., De Schepper, S., Forwick, M., Matthiessen, J. (2017). Neogene dinoflagellate cysts and acritarchs from the high northern latitudes and their relation to sea surface temperature. Marine Micropaleontology. 136:51-65. The accepted version is available in the main thesis. The article is also available at: http://dx.doi.org/10.1016/j.marmicro.2017.09.003 https://hdl.handle.net/1956/16992 cristin:1522847 Copyright the Author. All rights reserved Doctoral thesis 2017 ftunivbergen https://doi.org/10.1016/j.epsl.2017.10.01110.1016/j.marmicro.2017.09.003 2023-03-14T17:39:26Z Sea ice plays a crucial role in the climate system. Although this is broadly acknowledged, the role of sea ice is not fully understood, especially during warmer periods such as the Pliocene (5.88–2.58 Million years (Ma) ago). Fragmentary evidence suggests that the Arctic sea ice was reduced in the Pliocene, but that it could have been transported into the Nordic Seas, when the East Greenland Current (EGC) developed, which established the modern Nordic Seas circulation. Today the EGC is the main exporter of cooler and fresher Arctic water masses into the Nordic Seas and carries 90% of the total sea ice exported from the Arctic Ocean with it. The main objectives of this thesis are to determine the presence of (seasonal) sea ice in the Pliocene Iceland and Labrador Seas and to identify the role of the EGC and sea ice on the Pliocene (sub-)Arctic climate. The Iceland Sea and the Labrador Sea are important and sensitive regions for determining the occurrence of sea ice and changes in the EGC and Greenland Ice Sheet (GIS). Therefore, Early Pliocene to Early Quaternary sediments were investigated from the Iceland Sea (ODP Site 907) and the Labrador Sea (IODP Site U1307) using biomarkers (IP25, sterols, alkenones) to reconstruct the Pliocene paleoceanography and especially the sea ice cover in both areas. Additional information was obtained from palynological analysis of the same sites. My analyses revealed, that sea ice occurred for the first time in the Pliocene Iceland Sea around 4.5 Ma, together with a cooling of the entire Nordic Seas. The development of a proto EGC replaced warmer Atlantic water masses in the Iceland Sea and either favored the local formation of sea ice or directly exported sea ice from the Arctic Ocean. At ~4.0 Ma, an extended interval of seasonal sea ice in the Iceland Sea occurred contemporaneously with the establishment of a large sea surface temperature (SST) gradient in the Nordic Seas: the Iceland Sea cooled further, whereas the Norwegian Sea warmed. Increased warming in the North Atlantic ... Doctoral or Postdoctoral Thesis Arctic Arctic Ocean East Greenland east greenland current Greenland Ice Sheet Iceland Labrador Sea Nordic Seas North Atlantic Norwegian Sea Sea ice University of Bergen: Bergen Open Research Archive (BORA-UiB) Arctic Arctic Ocean Greenland Norwegian Sea Earth and Planetary Science Letters 481 61 72 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
Sea ice plays a crucial role in the climate system. Although this is broadly acknowledged, the role of sea ice is not fully understood, especially during warmer periods such as the Pliocene (5.88–2.58 Million years (Ma) ago). Fragmentary evidence suggests that the Arctic sea ice was reduced in the Pliocene, but that it could have been transported into the Nordic Seas, when the East Greenland Current (EGC) developed, which established the modern Nordic Seas circulation. Today the EGC is the main exporter of cooler and fresher Arctic water masses into the Nordic Seas and carries 90% of the total sea ice exported from the Arctic Ocean with it. The main objectives of this thesis are to determine the presence of (seasonal) sea ice in the Pliocene Iceland and Labrador Seas and to identify the role of the EGC and sea ice on the Pliocene (sub-)Arctic climate. The Iceland Sea and the Labrador Sea are important and sensitive regions for determining the occurrence of sea ice and changes in the EGC and Greenland Ice Sheet (GIS). Therefore, Early Pliocene to Early Quaternary sediments were investigated from the Iceland Sea (ODP Site 907) and the Labrador Sea (IODP Site U1307) using biomarkers (IP25, sterols, alkenones) to reconstruct the Pliocene paleoceanography and especially the sea ice cover in both areas. Additional information was obtained from palynological analysis of the same sites. My analyses revealed, that sea ice occurred for the first time in the Pliocene Iceland Sea around 4.5 Ma, together with a cooling of the entire Nordic Seas. The development of a proto EGC replaced warmer Atlantic water masses in the Iceland Sea and either favored the local formation of sea ice or directly exported sea ice from the Arctic Ocean. At ~4.0 Ma, an extended interval of seasonal sea ice in the Iceland Sea occurred contemporaneously with the establishment of a large sea surface temperature (SST) gradient in the Nordic Seas: the Iceland Sea cooled further, whereas the Norwegian Sea warmed. Increased warming in the North Atlantic ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Clotten, Caroline |
spellingShingle |
Clotten, Caroline Pliocene sea ice evolution in the Iceland and Labrador Sea – A biomarker approach |
author_facet |
Clotten, Caroline |
author_sort |
Clotten, Caroline |
title |
Pliocene sea ice evolution in the Iceland and Labrador Sea – A biomarker approach |
title_short |
Pliocene sea ice evolution in the Iceland and Labrador Sea – A biomarker approach |
title_full |
Pliocene sea ice evolution in the Iceland and Labrador Sea – A biomarker approach |
title_fullStr |
Pliocene sea ice evolution in the Iceland and Labrador Sea – A biomarker approach |
title_full_unstemmed |
Pliocene sea ice evolution in the Iceland and Labrador Sea – A biomarker approach |
title_sort |
pliocene sea ice evolution in the iceland and labrador sea – a biomarker approach |
publisher |
The University of Bergen |
publishDate |
2017 |
url |
https://hdl.handle.net/1956/16992 |
geographic |
Arctic Arctic Ocean Greenland Norwegian Sea |
geographic_facet |
Arctic Arctic Ocean Greenland Norwegian Sea |
genre |
Arctic Arctic Ocean East Greenland east greenland current Greenland Ice Sheet Iceland Labrador Sea Nordic Seas North Atlantic Norwegian Sea Sea ice |
genre_facet |
Arctic Arctic Ocean East Greenland east greenland current Greenland Ice Sheet Iceland Labrador Sea Nordic Seas North Atlantic Norwegian Sea Sea ice |
op_relation |
Paper I: Clotten, C., Stein, R., Fahl, K., Schreck, M., De Schepper, S. On the Causes of Sea Ice in the Early Pliocene Iceland Sea. Full text not available in BORA. Clotten, C., Stein, R., Fahl, K., De Schepper, S (2018). Seasonal sea ice cover during the warm Pliocene: evidence from the Iceland Sea (ODP Site 907). Earth and Planetary Science Letters. 481:61-72. The accepted version is available in the main thesis. The article is also available at: http://dx.doi.org/10.1016/j.epsl.2017.10.011 Paper III: Clotten, C., Stein, R., Fahl, K., De Schepper, S. Sea ice presence in the Labrador Sea prior to the Northern Hemisphere Glaciation. Full text not available in BORA. Paper IV: Schreck, M., Nam, S.-I., Clotten, C., Fahl, K., De Schepper, S., Forwick, M., Matthiessen, J. (2017). Neogene dinoflagellate cysts and acritarchs from the high northern latitudes and their relation to sea surface temperature. Marine Micropaleontology. 136:51-65. The accepted version is available in the main thesis. The article is also available at: http://dx.doi.org/10.1016/j.marmicro.2017.09.003 https://hdl.handle.net/1956/16992 cristin:1522847 |
op_rights |
Copyright the Author. All rights reserved |
op_doi |
https://doi.org/10.1016/j.epsl.2017.10.01110.1016/j.marmicro.2017.09.003 |
container_title |
Earth and Planetary Science Letters |
container_volume |
481 |
container_start_page |
61 |
op_container_end_page |
72 |
_version_ |
1766322283377328128 |