Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea
Seafloor spreading can be explained by different dynamic mechanisms, magmatically or tectonically dominated. The Southwest Sub-basin, located at the southwest tip of the propagating seafloor spreading of the South China Sea, remains unclear for its spreading regime owing to poor and debated knowledg...
Published in: | Geochemistry, Geophysics, Geosystems |
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Language: | English |
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Online Access: | http://ir.gig.ac.cn/handle/344008/40112 https://doi.org/10.1029/2018GC007819 |
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ftchacadscgigcas:oai:ir.gig.ac.cn:344008/40112 2023-05-15T17:06:11+02:00 Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea Yu, Junhui Yan, Pin Wang, Yanlin Zhang, Jinchang Qiu, Yan Pubellier, Manuel Delescluse, Matthias 2018-09-01 http://ir.gig.ac.cn/handle/344008/40112 https://doi.org/10.1029/2018GC007819 英语 eng AMER GEOPHYSICAL UNION GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS http://ir.gig.ac.cn/handle/344008/40112 doi:10.1029/2018GC007819 Geochemistry & Geophysics OCEAN-CONTINENT TRANSITION CENTRAL TYRRHENIAN BASIN DEEP-CRUSTAL STRUCTURE IODP EXPEDITION 349 EAST PACIFIC RISE LABRADOR SEA VELOCITY STRUCTURE EXHUMED MANTLE INDIAN RIDGE FLEMISH CAP 期刊论文 2018 ftchacadscgigcas https://doi.org/10.1029/2018GC007819 2020-12-22T07:21:34Z Seafloor spreading can be explained by different dynamic mechanisms, magmatically or tectonically dominated. The Southwest Sub-basin, located at the southwest tip of the propagating seafloor spreading of the South China Sea, remains unclear for its spreading regime owing to poor and debated knowledge of the crustal structures. Here two multichannel seismic lines and one oceanic bottom seismometer line across this subbasin are reprocessed and analyzed with focus on crustal imaging. The sediments are usually 0.5-1.0 km thick over the abyssal basin and slightly thicker in the few grabens. The thickest (3.3 km) sediments are found in the fossil spreading center. The basement is fairly rough and highly faulted by ubiquitous crustal faults. The fossil spreading center is characterized by a deep median valley, similar to that of magma-poor spreading cases. Both multichannel seismic lines show a few intermittent and diffusive reflectors at 1.5- to 3.6- km depth below the fragmented basement. These reflectors, correlating well with the velocities of 6.8-7.2 km/s obtained from velocity inversion of oceanic bottom seismometer data, are interpreted as Moho reflections. Thus, the inferred crustal thickness is only 1.5-3.6 km excluding the sediments, which is much thinner than usual. The underlying mantle with velocities lower than 8.0 km/s might be serpentinized with water infiltration along these crustal faults. Therefore, it is proposed that the spreading of the Southwest Sub-basin was tectonically dominated. Report Labrador Sea Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) Indian Pacific Geochemistry, Geophysics, Geosystems 19 9 3459 3477 |
institution |
Open Polar |
collection |
Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) |
op_collection_id |
ftchacadscgigcas |
language |
English |
topic |
Geochemistry & Geophysics OCEAN-CONTINENT TRANSITION CENTRAL TYRRHENIAN BASIN DEEP-CRUSTAL STRUCTURE IODP EXPEDITION 349 EAST PACIFIC RISE LABRADOR SEA VELOCITY STRUCTURE EXHUMED MANTLE INDIAN RIDGE FLEMISH CAP |
spellingShingle |
Geochemistry & Geophysics OCEAN-CONTINENT TRANSITION CENTRAL TYRRHENIAN BASIN DEEP-CRUSTAL STRUCTURE IODP EXPEDITION 349 EAST PACIFIC RISE LABRADOR SEA VELOCITY STRUCTURE EXHUMED MANTLE INDIAN RIDGE FLEMISH CAP Yu, Junhui Yan, Pin Wang, Yanlin Zhang, Jinchang Qiu, Yan Pubellier, Manuel Delescluse, Matthias Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea |
topic_facet |
Geochemistry & Geophysics OCEAN-CONTINENT TRANSITION CENTRAL TYRRHENIAN BASIN DEEP-CRUSTAL STRUCTURE IODP EXPEDITION 349 EAST PACIFIC RISE LABRADOR SEA VELOCITY STRUCTURE EXHUMED MANTLE INDIAN RIDGE FLEMISH CAP |
description |
Seafloor spreading can be explained by different dynamic mechanisms, magmatically or tectonically dominated. The Southwest Sub-basin, located at the southwest tip of the propagating seafloor spreading of the South China Sea, remains unclear for its spreading regime owing to poor and debated knowledge of the crustal structures. Here two multichannel seismic lines and one oceanic bottom seismometer line across this subbasin are reprocessed and analyzed with focus on crustal imaging. The sediments are usually 0.5-1.0 km thick over the abyssal basin and slightly thicker in the few grabens. The thickest (3.3 km) sediments are found in the fossil spreading center. The basement is fairly rough and highly faulted by ubiquitous crustal faults. The fossil spreading center is characterized by a deep median valley, similar to that of magma-poor spreading cases. Both multichannel seismic lines show a few intermittent and diffusive reflectors at 1.5- to 3.6- km depth below the fragmented basement. These reflectors, correlating well with the velocities of 6.8-7.2 km/s obtained from velocity inversion of oceanic bottom seismometer data, are interpreted as Moho reflections. Thus, the inferred crustal thickness is only 1.5-3.6 km excluding the sediments, which is much thinner than usual. The underlying mantle with velocities lower than 8.0 km/s might be serpentinized with water infiltration along these crustal faults. Therefore, it is proposed that the spreading of the Southwest Sub-basin was tectonically dominated. |
format |
Report |
author |
Yu, Junhui Yan, Pin Wang, Yanlin Zhang, Jinchang Qiu, Yan Pubellier, Manuel Delescluse, Matthias |
author_facet |
Yu, Junhui Yan, Pin Wang, Yanlin Zhang, Jinchang Qiu, Yan Pubellier, Manuel Delescluse, Matthias |
author_sort |
Yu, Junhui |
title |
Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea |
title_short |
Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea |
title_full |
Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea |
title_fullStr |
Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea |
title_full_unstemmed |
Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea |
title_sort |
seismic evidence for tectonically dominated seafloor spreading in the southwest sub-basin of the south china sea |
publisher |
AMER GEOPHYSICAL UNION |
publishDate |
2018 |
url |
http://ir.gig.ac.cn/handle/344008/40112 https://doi.org/10.1029/2018GC007819 |
geographic |
Indian Pacific |
geographic_facet |
Indian Pacific |
genre |
Labrador Sea |
genre_facet |
Labrador Sea |
op_relation |
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS http://ir.gig.ac.cn/handle/344008/40112 doi:10.1029/2018GC007819 |
op_doi |
https://doi.org/10.1029/2018GC007819 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
19 |
container_issue |
9 |
container_start_page |
3459 |
op_container_end_page |
3477 |
_version_ |
1766061215225741312 |