The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

The Middle Miocene Climatic Transition (MMCT, approximately 14 Ma) is a key period in Cenozoic cooling and cryospheric expansion. Despite being well documented in isotopic record, the causes of the MMCT are still a matter of debate. Among various hypotheses, some authors suggested that it was due th...

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Published in:Climate of the Past
Main Authors: Hamon, N., Sepulchre, P., Lefebvre, V., Ramstein, G.
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2013
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Online Access:https://doi.org/10.5194/cp-9-2687-2013
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spelling ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00020984 2023-05-15T13:41:02+02:00 The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma) Hamon, N. Sepulchre, P. Lefebvre, V. Ramstein, G. 2013-11 electronic https://doi.org/10.5194/cp-9-2687-2013 https://noa.gwlb.de/receive/cop_mods_00020984 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020939/cp-9-2687-2013.pdf https://cp.copernicus.org/articles/9/2687/2013/cp-9-2687-2013.pdf eng eng Copernicus Publications Climate of the Past -- http://www.copernicus.org/EGU/cp/cp/published_papers.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2217985 -- 1814-9332 https://doi.org/10.5194/cp-9-2687-2013 https://noa.gwlb.de/receive/cop_mods_00020984 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020939/cp-9-2687-2013.pdf https://cp.copernicus.org/articles/9/2687/2013/cp-9-2687-2013.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2013 ftnonlinearchiv https://doi.org/10.5194/cp-9-2687-2013 2022-02-08T22:51:54Z The Middle Miocene Climatic Transition (MMCT, approximately 14 Ma) is a key period in Cenozoic cooling and cryospheric expansion. Despite being well documented in isotopic record, the causes of the MMCT are still a matter of debate. Among various hypotheses, some authors suggested that it was due the final closure of the eastern Tethys seaway and subsequent oceanic circulation reorganisation. The aim of the present study is to quantify the impact of varying Tethys seaway depths on middle Miocene ocean and climate, in order to better understand its role in the MMCT. We present four sensitivity experiments with a fully coupled ocean-atmosphere general circulation model. Our results indicate the presence of a warm and salty water source in the northern Indian Ocean when the eastern Tethys is deep open (4000 or 1000 m), which corresponds to the Tethyan Indian Saline Water (TISW) described on the basis of isotopic studies. This water source is absent in the experiments with shallow (250 m) and closed Tethys seaway, inducing strong changes in the latitudinal density gradient and ultimately the reinforcement of the Antarctic Circumpolar Current (ACC). Moreover, when the Tethys seaway is shallow or closed, there is a westward water flow in the Gibraltar Strait that strengthens the Atlantic Meridional Overturning Circulation (AMOC) compared to the experiments with deep-open Tethys seaway. Our results therefore suggest that the shoaling and final closure of the eastern Tethys seaway played a major role in the oceanic circulation reorganisation during the middle Miocene. The results presented here provide new constraints on the timing of the Tethys seaway closure and particularly indicate that, prior to 14 Ma, a deep-open Tethys seaway should have allowed the formation of TISW. Moreover, whereas the final closure of this seaway likely played a major role in the reorganisation of oceanic circulation, we suggest that it was not the main driver of the global cooling and Antarctica ice-sheet expansion during the MMCT. Here we propose that the initiation of the MMCT was caused by an atmospheric pCO2 drawdown and that the oceanic changes due to the Tethys seaway closure amplified the response of global climate and East Antarctic Ice Sheet. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Niedersächsisches Online-Archiv NOA Antarctic East Antarctic Ice Sheet Indian The Antarctic Climate of the Past 9 6 2687 2702
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collection Niedersächsisches Online-Archiv NOA
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language English
topic article
Verlagsveröffentlichung
spellingShingle article
Verlagsveröffentlichung
Hamon, N.
Sepulchre, P.
Lefebvre, V.
Ramstein, G.
The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)
topic_facet article
Verlagsveröffentlichung
description The Middle Miocene Climatic Transition (MMCT, approximately 14 Ma) is a key period in Cenozoic cooling and cryospheric expansion. Despite being well documented in isotopic record, the causes of the MMCT are still a matter of debate. Among various hypotheses, some authors suggested that it was due the final closure of the eastern Tethys seaway and subsequent oceanic circulation reorganisation. The aim of the present study is to quantify the impact of varying Tethys seaway depths on middle Miocene ocean and climate, in order to better understand its role in the MMCT. We present four sensitivity experiments with a fully coupled ocean-atmosphere general circulation model. Our results indicate the presence of a warm and salty water source in the northern Indian Ocean when the eastern Tethys is deep open (4000 or 1000 m), which corresponds to the Tethyan Indian Saline Water (TISW) described on the basis of isotopic studies. This water source is absent in the experiments with shallow (250 m) and closed Tethys seaway, inducing strong changes in the latitudinal density gradient and ultimately the reinforcement of the Antarctic Circumpolar Current (ACC). Moreover, when the Tethys seaway is shallow or closed, there is a westward water flow in the Gibraltar Strait that strengthens the Atlantic Meridional Overturning Circulation (AMOC) compared to the experiments with deep-open Tethys seaway. Our results therefore suggest that the shoaling and final closure of the eastern Tethys seaway played a major role in the oceanic circulation reorganisation during the middle Miocene. The results presented here provide new constraints on the timing of the Tethys seaway closure and particularly indicate that, prior to 14 Ma, a deep-open Tethys seaway should have allowed the formation of TISW. Moreover, whereas the final closure of this seaway likely played a major role in the reorganisation of oceanic circulation, we suggest that it was not the main driver of the global cooling and Antarctica ice-sheet expansion during the MMCT. Here we propose that the initiation of the MMCT was caused by an atmospheric pCO2 drawdown and that the oceanic changes due to the Tethys seaway closure amplified the response of global climate and East Antarctic Ice Sheet.
format Article in Journal/Newspaper
author Hamon, N.
Sepulchre, P.
Lefebvre, V.
Ramstein, G.
author_facet Hamon, N.
Sepulchre, P.
Lefebvre, V.
Ramstein, G.
author_sort Hamon, N.
title The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)
title_short The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)
title_full The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)
title_fullStr The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)
title_full_unstemmed The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)
title_sort role of eastern tethys seaway closure in the middle miocene climatic transition (ca. 14 ma)
publisher Copernicus Publications
publishDate 2013
url https://doi.org/10.5194/cp-9-2687-2013
https://noa.gwlb.de/receive/cop_mods_00020984
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020939/cp-9-2687-2013.pdf
https://cp.copernicus.org/articles/9/2687/2013/cp-9-2687-2013.pdf
geographic Antarctic
East Antarctic Ice Sheet
Indian
The Antarctic
geographic_facet Antarctic
East Antarctic Ice Sheet
Indian
The Antarctic
genre Antarc*
Antarctic
Antarctica
Ice Sheet
genre_facet Antarc*
Antarctic
Antarctica
Ice Sheet
op_relation Climate of the Past -- http://www.copernicus.org/EGU/cp/cp/published_papers.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2217985 -- 1814-9332
https://doi.org/10.5194/cp-9-2687-2013
https://noa.gwlb.de/receive/cop_mods_00020984
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020939/cp-9-2687-2013.pdf
https://cp.copernicus.org/articles/9/2687/2013/cp-9-2687-2013.pdf
op_rights uneingeschränkt
info:eu-repo/semantics/openAccess
op_doi https://doi.org/10.5194/cp-9-2687-2013
container_title Climate of the Past
container_volume 9
container_issue 6
container_start_page 2687
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