Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene
The vigorous eastward flow of the Antarctic Circumpolar Current (ACC) connects all major ocean basins and plays a prominent role in the transport of heat, carbon and nutrients around the globe. However, the establishment of a deep circumpolar flow, similar to the present-day ACC, remains controversi...
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2022
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ftunivutrecht:oai:dspace.library.uu.nl:1874/417995 2023-07-23T04:15:14+02:00 Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene Evangelinos, Dimitris Escutia, Carlota van de Flierdt, Tina Valero, Luis Flores, José Abel Harwood, David M. Hoem, Frida S. Bijl, Peter Etourneau, Johan Kreissig, Katharina Nilsson-Kerr, Katrina Holder, Liam López-Quirós, Adrián Salabarnada, Ariadna Marine palynology and palaeoceanography Marine Palynology 2022-01 application/pdf https://dspace.library.uu.nl/handle/1874/417995 en eng 0921-8181 https://dspace.library.uu.nl/handle/1874/417995 info:eu-repo/semantics/ClosedAccess ACC CDW Deep ocean circulation Neodymium isotope ratios Oligocene-early Miocene Tasmanian Gateway Global and Planetary Change Oceanography Article 2022 ftunivutrecht 2023-07-02T03:35:46Z The vigorous eastward flow of the Antarctic Circumpolar Current (ACC) connects all major ocean basins and plays a prominent role in the transport of heat, carbon and nutrients around the globe. However, the establishment of a deep circumpolar flow, similar to the present-day ACC, remains controversial thereby obscuring our understanding of its climatic impact. Deciphering the chemical composition of Circumpolar Deep Water (CDW) within the ACC can provide critical insights about its development and evolution. Here we present new fossil fish teeth/bone debris neodymium isotope (εNd) records from Deep Sea Drilling Project (DSDP) Sites 278 and 274 in the southwest Pacific Ocean, with the aim to trace changes in deep water masses across the Tasmanian Gateway between the early Oligocene and early Miocene (~ 33–22 Ma). Site 274 provides the first Nd isotope record proximal to the Ross Sea during the Oligocene (33.5–23.4 Ma). Its Nd isotope composition shows excursions to very radiogenic values, εNd(t) = −3.1 and εNd(t)= − 3.7, at 33.5 Ma and 23.8 Ma, respectively, in response to major steps in Antarctic ice sheet expansion. A shift to lower, more unradiogenic εNd(t) values between 29.7 and 29.1 Ma is linked to an increased influence of proto-CDW upwelling at the site. In contrast, the Nd isotope record from Site 278 in the southern Emerald Basin shows little variability (εNd(t) = −6.0 to −6.7) throughout the Oligocene and early Miocene (30.9–21.8 Ma). Comparison with published data north of the ACC path, demonstrates the presence of two deep water masses in the South Pacific prior to the inferred onset of the ACC (33–30 Ma), one occupying depths between ~2500 and 3000 m (εNd(t)= ~ −3 to −5) and a deep/bottom water mass (> 3000 m) with a more unradiogenic Nd isotope composition (εNd(t)= ~ −6). Site 278 located close to the proto-polar front (proto-PF) indicates that following the inferred onset of the ACC, deep waters bathing the southern Emerald Basin remained more radiogenic in the Southwest Pacific compared to ... Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ross Sea Utrecht University Repository Antarctic Emerald Basin ENVELOPE(162.500,162.500,-54.000,-54.000) Pacific Ross Sea The Antarctic |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
ACC CDW Deep ocean circulation Neodymium isotope ratios Oligocene-early Miocene Tasmanian Gateway Global and Planetary Change Oceanography |
spellingShingle |
ACC CDW Deep ocean circulation Neodymium isotope ratios Oligocene-early Miocene Tasmanian Gateway Global and Planetary Change Oceanography Evangelinos, Dimitris Escutia, Carlota van de Flierdt, Tina Valero, Luis Flores, José Abel Harwood, David M. Hoem, Frida S. Bijl, Peter Etourneau, Johan Kreissig, Katharina Nilsson-Kerr, Katrina Holder, Liam López-Quirós, Adrián Salabarnada, Ariadna Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene |
topic_facet |
ACC CDW Deep ocean circulation Neodymium isotope ratios Oligocene-early Miocene Tasmanian Gateway Global and Planetary Change Oceanography |
description |
The vigorous eastward flow of the Antarctic Circumpolar Current (ACC) connects all major ocean basins and plays a prominent role in the transport of heat, carbon and nutrients around the globe. However, the establishment of a deep circumpolar flow, similar to the present-day ACC, remains controversial thereby obscuring our understanding of its climatic impact. Deciphering the chemical composition of Circumpolar Deep Water (CDW) within the ACC can provide critical insights about its development and evolution. Here we present new fossil fish teeth/bone debris neodymium isotope (εNd) records from Deep Sea Drilling Project (DSDP) Sites 278 and 274 in the southwest Pacific Ocean, with the aim to trace changes in deep water masses across the Tasmanian Gateway between the early Oligocene and early Miocene (~ 33–22 Ma). Site 274 provides the first Nd isotope record proximal to the Ross Sea during the Oligocene (33.5–23.4 Ma). Its Nd isotope composition shows excursions to very radiogenic values, εNd(t) = −3.1 and εNd(t)= − 3.7, at 33.5 Ma and 23.8 Ma, respectively, in response to major steps in Antarctic ice sheet expansion. A shift to lower, more unradiogenic εNd(t) values between 29.7 and 29.1 Ma is linked to an increased influence of proto-CDW upwelling at the site. In contrast, the Nd isotope record from Site 278 in the southern Emerald Basin shows little variability (εNd(t) = −6.0 to −6.7) throughout the Oligocene and early Miocene (30.9–21.8 Ma). Comparison with published data north of the ACC path, demonstrates the presence of two deep water masses in the South Pacific prior to the inferred onset of the ACC (33–30 Ma), one occupying depths between ~2500 and 3000 m (εNd(t)= ~ −3 to −5) and a deep/bottom water mass (> 3000 m) with a more unradiogenic Nd isotope composition (εNd(t)= ~ −6). Site 278 located close to the proto-polar front (proto-PF) indicates that following the inferred onset of the ACC, deep waters bathing the southern Emerald Basin remained more radiogenic in the Southwest Pacific compared to ... |
author2 |
Marine palynology and palaeoceanography Marine Palynology |
format |
Article in Journal/Newspaper |
author |
Evangelinos, Dimitris Escutia, Carlota van de Flierdt, Tina Valero, Luis Flores, José Abel Harwood, David M. Hoem, Frida S. Bijl, Peter Etourneau, Johan Kreissig, Katharina Nilsson-Kerr, Katrina Holder, Liam López-Quirós, Adrián Salabarnada, Ariadna |
author_facet |
Evangelinos, Dimitris Escutia, Carlota van de Flierdt, Tina Valero, Luis Flores, José Abel Harwood, David M. Hoem, Frida S. Bijl, Peter Etourneau, Johan Kreissig, Katharina Nilsson-Kerr, Katrina Holder, Liam López-Quirós, Adrián Salabarnada, Ariadna |
author_sort |
Evangelinos, Dimitris |
title |
Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene |
title_short |
Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene |
title_full |
Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene |
title_fullStr |
Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene |
title_full_unstemmed |
Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene |
title_sort |
absence of a strong, deep-reaching antarctic circumpolar current zonal flow across the tasmanian gateway during the oligocene to early miocene |
publishDate |
2022 |
url |
https://dspace.library.uu.nl/handle/1874/417995 |
long_lat |
ENVELOPE(162.500,162.500,-54.000,-54.000) |
geographic |
Antarctic Emerald Basin Pacific Ross Sea The Antarctic |
geographic_facet |
Antarctic Emerald Basin Pacific Ross Sea The Antarctic |
genre |
Antarc* Antarctic Ice Sheet Ross Sea |
genre_facet |
Antarc* Antarctic Ice Sheet Ross Sea |
op_relation |
0921-8181 https://dspace.library.uu.nl/handle/1874/417995 |
op_rights |
info:eu-repo/semantics/ClosedAccess |
_version_ |
1772189239602053120 |