Crustal structure and rift flank uplift of the Adare Trough, Antarctica
The Adare Trough, located 100 km northeast of Cape Adare, Antarctica, represents the extinct third arm of a Tertiary spreading ridge between East and West Antarctica. It is characterized by pronounced asymmetric rift flanks elevated up to over 2 km above the trough's basement, accompanied by a...
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American Geophysical Union
2005
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Online Access: | https://doi.org/10.1029/2005GC001027 |
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ftcaltechauth:oai:authors.library.caltech.edu:pbq3e-wpq66 2024-06-23T07:46:44+00:00 Crustal structure and rift flank uplift of the Adare Trough, Antarctica Müller, R. Dietmar Cande, Steven C. Stock, Joann M. Keller, William R. 2005-11-23 https://doi.org/10.1029/2005GC001027 unknown American Geophysical Union https://doi.org/10.1029/2005GC001027 oai:authors.library.caltech.edu:pbq3e-wpq66 eprintid:1107 resolverid:CaltechAUTHORS:MULggg05 info:eu-repo/semantics/openAccess Other Geochemistry, Geophysics, Geosystems, 6(11), 2005GC001027, (2005-11-23) Adare Trough Antarctica depth anomaly extinct ridge flexure rift 0930 Exploration Geophysics: Oceanic structures 3010 Marine Geology and Geophysics: Gravity and isostasy (1218 1222) 3035 Marine Geology and Geophysics: Midocean ridge processes info:eu-repo/semantics/article 2005 ftcaltechauth https://doi.org/10.1029/2005GC001027 2024-06-12T03:27:39Z The Adare Trough, located 100 km northeast of Cape Adare, Antarctica, represents the extinct third arm of a Tertiary spreading ridge between East and West Antarctica. It is characterized by pronounced asymmetric rift flanks elevated up to over 2 km above the trough's basement, accompanied by a large positive mantle Bouguer anomaly. On the basis of recently acquired seismic reflection and ship gravity data, we invert mantle Bouguer anomalies from the Adare Trough and obtain an unexpectedly large oceanic crustal thickness maximum of 9–10.5 km underneath the extinct ridge. A regional positive residual basement depth anomaly between 1 and 2.5 km in amplitude characterizes ocean crust from offshore Victoria Land to the Balleny Islands and north of Iselin Bank. The observations and models indicate that the mid/late Tertiary episode of slow spreading between East and West Antarctica was associated with a mantle thermal anomaly. The increasing crustal thickness toward the extinct ridge indicates that this thermal mantle anomaly may have increased in amplitude through time during the Adare spreading episode. This scenario is supported by a mantle convection model, which indicates the formation and strengthening of a major regional negative upper mantle density anomaly in the southwest Pacific in the last 50 million years. The total amount of post-26 Ma extension associated with Adare Trough normal faulting was about 7.5 km, in anomalously thick oceanic crust with a lithospheric effective elastic thickness (EET) between 3.5 and 5 km. This corresponds to an age between 3 and 5 million years based on a thermal boundary layer model and supports a scenario in which the Adare Trough formed soon after spreading between East and West Antarctica ceased, confined to relatively weak lithosphere with anomalously thick oceanic crust. There is little evidence for major subsequent structural activity in the Adare trough area from the available seismic data, indicating that this part of the West Antarctic Rift system became largely ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Balleny Islands Victoria Land West Antarctica Caltech Authors (California Institute of Technology) Adare ENVELOPE(170.233,170.233,-71.283,-71.283) Adare Trough ENVELOPE(172.500,172.500,-70.033,-70.033) Antarctic Balleny Islands Cape Adare ENVELOPE(175.000,175.000,-71.000,-71.000) Iselin Bank ENVELOPE(-179.000,-179.000,-72.500,-72.500) Pacific Victoria Land West Antarctica Geochemistry, Geophysics, Geosystems 6 11 |
institution |
Open Polar |
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Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
unknown |
topic |
Adare Trough Antarctica depth anomaly extinct ridge flexure rift 0930 Exploration Geophysics: Oceanic structures 3010 Marine Geology and Geophysics: Gravity and isostasy (1218 1222) 3035 Marine Geology and Geophysics: Midocean ridge processes |
spellingShingle |
Adare Trough Antarctica depth anomaly extinct ridge flexure rift 0930 Exploration Geophysics: Oceanic structures 3010 Marine Geology and Geophysics: Gravity and isostasy (1218 1222) 3035 Marine Geology and Geophysics: Midocean ridge processes Müller, R. Dietmar Cande, Steven C. Stock, Joann M. Keller, William R. Crustal structure and rift flank uplift of the Adare Trough, Antarctica |
topic_facet |
Adare Trough Antarctica depth anomaly extinct ridge flexure rift 0930 Exploration Geophysics: Oceanic structures 3010 Marine Geology and Geophysics: Gravity and isostasy (1218 1222) 3035 Marine Geology and Geophysics: Midocean ridge processes |
description |
The Adare Trough, located 100 km northeast of Cape Adare, Antarctica, represents the extinct third arm of a Tertiary spreading ridge between East and West Antarctica. It is characterized by pronounced asymmetric rift flanks elevated up to over 2 km above the trough's basement, accompanied by a large positive mantle Bouguer anomaly. On the basis of recently acquired seismic reflection and ship gravity data, we invert mantle Bouguer anomalies from the Adare Trough and obtain an unexpectedly large oceanic crustal thickness maximum of 9–10.5 km underneath the extinct ridge. A regional positive residual basement depth anomaly between 1 and 2.5 km in amplitude characterizes ocean crust from offshore Victoria Land to the Balleny Islands and north of Iselin Bank. The observations and models indicate that the mid/late Tertiary episode of slow spreading between East and West Antarctica was associated with a mantle thermal anomaly. The increasing crustal thickness toward the extinct ridge indicates that this thermal mantle anomaly may have increased in amplitude through time during the Adare spreading episode. This scenario is supported by a mantle convection model, which indicates the formation and strengthening of a major regional negative upper mantle density anomaly in the southwest Pacific in the last 50 million years. The total amount of post-26 Ma extension associated with Adare Trough normal faulting was about 7.5 km, in anomalously thick oceanic crust with a lithospheric effective elastic thickness (EET) between 3.5 and 5 km. This corresponds to an age between 3 and 5 million years based on a thermal boundary layer model and supports a scenario in which the Adare Trough formed soon after spreading between East and West Antarctica ceased, confined to relatively weak lithosphere with anomalously thick oceanic crust. There is little evidence for major subsequent structural activity in the Adare trough area from the available seismic data, indicating that this part of the West Antarctic Rift system became largely ... |
format |
Article in Journal/Newspaper |
author |
Müller, R. Dietmar Cande, Steven C. Stock, Joann M. Keller, William R. |
author_facet |
Müller, R. Dietmar Cande, Steven C. Stock, Joann M. Keller, William R. |
author_sort |
Müller, R. Dietmar |
title |
Crustal structure and rift flank uplift of the Adare Trough, Antarctica |
title_short |
Crustal structure and rift flank uplift of the Adare Trough, Antarctica |
title_full |
Crustal structure and rift flank uplift of the Adare Trough, Antarctica |
title_fullStr |
Crustal structure and rift flank uplift of the Adare Trough, Antarctica |
title_full_unstemmed |
Crustal structure and rift flank uplift of the Adare Trough, Antarctica |
title_sort |
crustal structure and rift flank uplift of the adare trough, antarctica |
publisher |
American Geophysical Union |
publishDate |
2005 |
url |
https://doi.org/10.1029/2005GC001027 |
long_lat |
ENVELOPE(170.233,170.233,-71.283,-71.283) ENVELOPE(172.500,172.500,-70.033,-70.033) ENVELOPE(175.000,175.000,-71.000,-71.000) ENVELOPE(-179.000,-179.000,-72.500,-72.500) |
geographic |
Adare Adare Trough Antarctic Balleny Islands Cape Adare Iselin Bank Pacific Victoria Land West Antarctica |
geographic_facet |
Adare Adare Trough Antarctic Balleny Islands Cape Adare Iselin Bank Pacific Victoria Land West Antarctica |
genre |
Antarc* Antarctic Antarctica Balleny Islands Victoria Land West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Balleny Islands Victoria Land West Antarctica |
op_source |
Geochemistry, Geophysics, Geosystems, 6(11), 2005GC001027, (2005-11-23) |
op_relation |
https://doi.org/10.1029/2005GC001027 oai:authors.library.caltech.edu:pbq3e-wpq66 eprintid:1107 resolverid:CaltechAUTHORS:MULggg05 |
op_rights |
info:eu-repo/semantics/openAccess Other |
op_doi |
https://doi.org/10.1029/2005GC001027 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
6 |
container_issue |
11 |
_version_ |
1802647844650221568 |