New insights into the current- and past hydrology of the north-western subtropical Pacific Ocean over the past 25 kyr, based on investigations of the Nd isotopic composition of seawater and deep-sea sediments from the northern South China Sea
The aim of this study is to reconstruct the evolution of the hydrology of the western subtropical North Pacific Ocean by using εNd proxy analysed on foraminifera and dispersed authigenic ferromanganese oxide precipitates in sediments from deep-sea cores collected in the northern SCS. Before using th...
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Other Authors: | , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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HAL CCSD
2014
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Online Access: | https://theses.hal.science/tel-01362508 https://theses.hal.science/tel-01362508/document https://theses.hal.science/tel-01362508/file/VD2_WU_QIONG_08092014.pdf |
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ftccsdartic:oai:HAL:tel-01362508v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
Authigenic phases Paleohydrology Last glacial period Nd isotopic composition Seawater South China Sea Philippine Sea Hydrology Holocene Foraminifera Nepheloid layers Composition isotopique du Nd Holocène Paléohydrologie Dernière période glaciaire Phases authigéniques Foraminifères Couche néphéloïde Hydrologie Mer des Philippines Mer de Chine du Sud Eau de mer [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
Authigenic phases Paleohydrology Last glacial period Nd isotopic composition Seawater South China Sea Philippine Sea Hydrology Holocene Foraminifera Nepheloid layers Composition isotopique du Nd Holocène Paléohydrologie Dernière période glaciaire Phases authigéniques Foraminifères Couche néphéloïde Hydrologie Mer des Philippines Mer de Chine du Sud Eau de mer [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Wu, Qiong New insights into the current- and past hydrology of the north-western subtropical Pacific Ocean over the past 25 kyr, based on investigations of the Nd isotopic composition of seawater and deep-sea sediments from the northern South China Sea |
topic_facet |
Authigenic phases Paleohydrology Last glacial period Nd isotopic composition Seawater South China Sea Philippine Sea Hydrology Holocene Foraminifera Nepheloid layers Composition isotopique du Nd Holocène Paléohydrologie Dernière période glaciaire Phases authigéniques Foraminifères Couche néphéloïde Hydrologie Mer des Philippines Mer de Chine du Sud Eau de mer [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
The aim of this study is to reconstruct the evolution of the hydrology of the western subtropical North Pacific Ocean by using εNd proxy analysed on foraminifera and dispersed authigenic ferromanganese oxide precipitates in sediments from deep-sea cores collected in the northern SCS. Before using the εNd proxy on deep sea sediments of the SCS, Nd of 16 seawater profiles collected in the northern South China Sea (SCS) and the Philippine Sea were investigated to establish the εNd distribution of water masses along the tropical western Pacific and the SCS that, until now have not been documented. εNd values for mid- and deep-water masses of the Philippine Sea and the SCS range from -2.7 to -4.4 and generally increase slightly with water depth. In the Philippine Sea, εNd values for the North Pacific Intermediate Water (NPIW) reach- 2.7±0.4 at mid-depths (500 to 1400 m). Below ~1800 m, the Pacific Deep Water (PDW) is characterized by less radiogenic Nd (-4.1±0.5) indicating the instrusion of southern sourced water masses. For most of the stations in the Northern SCS, water masses below 1500m (PDW) display homogenous εNd values (~ -4.1) similar to those of the PDW in the Philippine Sea. εNd values for the South China Sea Intermediate Water (SCSIW, 500-1500m) vary from -3.0 to -3.9 as a result of the vertical mixing of the NPIW with the PDW in the SCS. Seawater εNd values for the SCS (~5.3 to -7.0) display local modification in areas where the water lies above sediment drift deposit systems. This implies that “boundary exchange” with unradiogenic sediments (around~11) may occur temporally and spatially and does not modify he Nd isotopic composition of the PDW in the Northern SCS. In a second step, seawater εNd extracted from cleaned planktonic foraminifera G. ruber has been investigated on core MD05-2904, collected at a deph of 2000m on the north-western margin of the SCS. This study was undertaken in order to reconstruct hydrological variations since the LGM in the western subtropical North Pacific. The εNd records ... |
author2 |
Géosciences Paris Sud (GEOPS) Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) Université Paris Sud - Paris XI Christophe Colin |
format |
Doctoral or Postdoctoral Thesis |
author |
Wu, Qiong |
author_facet |
Wu, Qiong |
author_sort |
Wu, Qiong |
title |
New insights into the current- and past hydrology of the north-western subtropical Pacific Ocean over the past 25 kyr, based on investigations of the Nd isotopic composition of seawater and deep-sea sediments from the northern South China Sea |
title_short |
New insights into the current- and past hydrology of the north-western subtropical Pacific Ocean over the past 25 kyr, based on investigations of the Nd isotopic composition of seawater and deep-sea sediments from the northern South China Sea |
title_full |
New insights into the current- and past hydrology of the north-western subtropical Pacific Ocean over the past 25 kyr, based on investigations of the Nd isotopic composition of seawater and deep-sea sediments from the northern South China Sea |
title_fullStr |
New insights into the current- and past hydrology of the north-western subtropical Pacific Ocean over the past 25 kyr, based on investigations of the Nd isotopic composition of seawater and deep-sea sediments from the northern South China Sea |
title_full_unstemmed |
New insights into the current- and past hydrology of the north-western subtropical Pacific Ocean over the past 25 kyr, based on investigations of the Nd isotopic composition of seawater and deep-sea sediments from the northern South China Sea |
title_sort |
new insights into the current- and past hydrology of the north-western subtropical pacific ocean over the past 25 kyr, based on investigations of the nd isotopic composition of seawater and deep-sea sediments from the northern south china sea |
publisher |
HAL CCSD |
publishDate |
2014 |
url |
https://theses.hal.science/tel-01362508 https://theses.hal.science/tel-01362508/document https://theses.hal.science/tel-01362508/file/VD2_WU_QIONG_08092014.pdf |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
https://theses.hal.science/tel-01362508 Geochemistry. Université Paris Sud - Paris XI, 2014. English. ⟨NNT : 2014PA112169⟩ |
op_relation |
NNT: 2014PA112169 tel-01362508 https://theses.hal.science/tel-01362508 https://theses.hal.science/tel-01362508/document https://theses.hal.science/tel-01362508/file/VD2_WU_QIONG_08092014.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766170649420627968 |
spelling |
ftccsdartic:oai:HAL:tel-01362508v1 2023-05-15T18:01:16+02:00 New insights into the current- and past hydrology of the north-western subtropical Pacific Ocean over the past 25 kyr, based on investigations of the Nd isotopic composition of seawater and deep-sea sediments from the northern South China Sea Etude de l'hydrologie de la Mer de Chine du Sud depuis la dernière période glaciaire à partir de la composition isotopique du Nd analysé dans les foraminifères Wu, Qiong Géosciences Paris Sud (GEOPS) Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) Université Paris Sud - Paris XI Christophe Colin 2014-09-08 https://theses.hal.science/tel-01362508 https://theses.hal.science/tel-01362508/document https://theses.hal.science/tel-01362508/file/VD2_WU_QIONG_08092014.pdf en eng HAL CCSD NNT: 2014PA112169 tel-01362508 https://theses.hal.science/tel-01362508 https://theses.hal.science/tel-01362508/document https://theses.hal.science/tel-01362508/file/VD2_WU_QIONG_08092014.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01362508 Geochemistry. Université Paris Sud - Paris XI, 2014. English. ⟨NNT : 2014PA112169⟩ Authigenic phases Paleohydrology Last glacial period Nd isotopic composition Seawater South China Sea Philippine Sea Hydrology Holocene Foraminifera Nepheloid layers Composition isotopique du Nd Holocène Paléohydrologie Dernière période glaciaire Phases authigéniques Foraminifères Couche néphéloïde Hydrologie Mer des Philippines Mer de Chine du Sud Eau de mer [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/doctoralThesis Theses 2014 ftccsdartic 2023-03-27T09:12:54Z The aim of this study is to reconstruct the evolution of the hydrology of the western subtropical North Pacific Ocean by using εNd proxy analysed on foraminifera and dispersed authigenic ferromanganese oxide precipitates in sediments from deep-sea cores collected in the northern SCS. Before using the εNd proxy on deep sea sediments of the SCS, Nd of 16 seawater profiles collected in the northern South China Sea (SCS) and the Philippine Sea were investigated to establish the εNd distribution of water masses along the tropical western Pacific and the SCS that, until now have not been documented. εNd values for mid- and deep-water masses of the Philippine Sea and the SCS range from -2.7 to -4.4 and generally increase slightly with water depth. In the Philippine Sea, εNd values for the North Pacific Intermediate Water (NPIW) reach- 2.7±0.4 at mid-depths (500 to 1400 m). Below ~1800 m, the Pacific Deep Water (PDW) is characterized by less radiogenic Nd (-4.1±0.5) indicating the instrusion of southern sourced water masses. For most of the stations in the Northern SCS, water masses below 1500m (PDW) display homogenous εNd values (~ -4.1) similar to those of the PDW in the Philippine Sea. εNd values for the South China Sea Intermediate Water (SCSIW, 500-1500m) vary from -3.0 to -3.9 as a result of the vertical mixing of the NPIW with the PDW in the SCS. Seawater εNd values for the SCS (~5.3 to -7.0) display local modification in areas where the water lies above sediment drift deposit systems. This implies that “boundary exchange” with unradiogenic sediments (around~11) may occur temporally and spatially and does not modify he Nd isotopic composition of the PDW in the Northern SCS. In a second step, seawater εNd extracted from cleaned planktonic foraminifera G. ruber has been investigated on core MD05-2904, collected at a deph of 2000m on the north-western margin of the SCS. This study was undertaken in order to reconstruct hydrological variations since the LGM in the western subtropical North Pacific. The εNd records ... Doctoral or Postdoctoral Thesis Planktonic foraminifera Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Pacific |