Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences
Extension during the middle Cenozoic (43–26 Ma) in the north end of the West Antarctic rift system (WARS) is well constrained by seafloor magnetic anomalies formed at the extinct Adare spreading axis. Kinematic solutions for this time interval suggest a southward decrease in relative motion between...
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American Geophysical Union
2010
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ftcaltechauth:oai:authors.library.caltech.edu:19709 2023-05-15T13:49:58+02:00 Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences Granot, R. Cande, S. C. Stock, J. M. Davey, F. J. Clayton, R. W. 2010-08-04 application/pdf https://authors.library.caltech.edu/19709/ https://authors.library.caltech.edu/19709/1/Granot2010p11186Geochem_Geophy_Geosy.pdf https://resolver.caltech.edu/CaltechAUTHORS:20100830-113018904 en eng American Geophysical Union https://authors.library.caltech.edu/19709/1/Granot2010p11186Geochem_Geophy_Geosy.pdf Granot, R. and Cande, S. C. and Stock, J. M. and Davey, F. J. and Clayton, R. W. (2010) Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences. Geochemistry, Geophysics, Geosystems, 11 . Art. No. Q08005 . ISSN 1525-2027. doi:10.1029/2010GC003105. https://resolver.caltech.edu/CaltechAUTHORS:20100830-113018904 <https://resolver.caltech.edu/CaltechAUTHORS:20100830-113018904> other Article PeerReviewed 2010 ftcaltechauth https://doi.org/10.1029/2010GC003105 2021-11-11T18:45:10Z Extension during the middle Cenozoic (43–26 Ma) in the north end of the West Antarctic rift system (WARS) is well constrained by seafloor magnetic anomalies formed at the extinct Adare spreading axis. Kinematic solutions for this time interval suggest a southward decrease in relative motion between East and West Antarctica. Here we present multichannel seismic reflection and seafloor mapping data acquired within and near the Adare Basin on a recent geophysical cruise. We have traced the ANTOSTRAT seismic stratigraphic framework from the northwest Ross Sea into the Adare Basin, verified and tied to DSDP drill sites 273 and 274. Our results reveal three distinct periods of tectonic activity. An early localized deformational event took place close to the cessation of seafloor spreading in the Adare Basin (~24 Ma). It reactivated a few normal faults and initiated the formation of the Adare Trough. A prominent pulse of rifting in the early Miocene (~17 Ma) resulted in normal faulting that initiated tilted blocks. The overall trend of structures was NE–SW, linking the event with the activity outside the basin. It resulted in major uplift of the Adare Trough and marks the last extensional phase of the Adare Basin. Recent volcanic vents (Pliocene to present day) tend to align with the early Miocene structures and the on-land Hallett volcanic province. This latest phase of tectonic activity also involves near-vertical normal faulting (still active in places) with negligible horizontal consequences. The early Miocene extensional event found within the Adare Basin does not require a change in the relative motion between East and West Antarctica. However, the lack of subsequent rifting within the Adare Basin coupled with the formation of the Terror Rift and an on-land and subice extension within the WARS require a pronounced change in the kinematics of the rift. These observations indicate that extension increased southward, therefore suggesting that a major change in relative plate motion took place in the middle Miocene. The late Miocene pole of rotation might have been located north of the Adare Basin, with opposite opening sign compared to the Eocene-Oligocene pole. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ross Sea West Antarctica Caltech Authors (California Institute of Technology) Adare ENVELOPE(170.233,170.233,-71.283,-71.283) Adare Basin ENVELOPE(175.000,175.000,-71.000,-71.000) Adare Trough ENVELOPE(172.500,172.500,-70.033,-70.033) Antarctic Hallett ENVELOPE(170.217,170.217,-72.317,-72.317) Ross Sea West Antarctica Geochemistry, Geophysics, Geosystems 11 8 n/a n/a |
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Open Polar |
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Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
English |
description |
Extension during the middle Cenozoic (43–26 Ma) in the north end of the West Antarctic rift system (WARS) is well constrained by seafloor magnetic anomalies formed at the extinct Adare spreading axis. Kinematic solutions for this time interval suggest a southward decrease in relative motion between East and West Antarctica. Here we present multichannel seismic reflection and seafloor mapping data acquired within and near the Adare Basin on a recent geophysical cruise. We have traced the ANTOSTRAT seismic stratigraphic framework from the northwest Ross Sea into the Adare Basin, verified and tied to DSDP drill sites 273 and 274. Our results reveal three distinct periods of tectonic activity. An early localized deformational event took place close to the cessation of seafloor spreading in the Adare Basin (~24 Ma). It reactivated a few normal faults and initiated the formation of the Adare Trough. A prominent pulse of rifting in the early Miocene (~17 Ma) resulted in normal faulting that initiated tilted blocks. The overall trend of structures was NE–SW, linking the event with the activity outside the basin. It resulted in major uplift of the Adare Trough and marks the last extensional phase of the Adare Basin. Recent volcanic vents (Pliocene to present day) tend to align with the early Miocene structures and the on-land Hallett volcanic province. This latest phase of tectonic activity also involves near-vertical normal faulting (still active in places) with negligible horizontal consequences. The early Miocene extensional event found within the Adare Basin does not require a change in the relative motion between East and West Antarctica. However, the lack of subsequent rifting within the Adare Basin coupled with the formation of the Terror Rift and an on-land and subice extension within the WARS require a pronounced change in the kinematics of the rift. These observations indicate that extension increased southward, therefore suggesting that a major change in relative plate motion took place in the middle Miocene. The late Miocene pole of rotation might have been located north of the Adare Basin, with opposite opening sign compared to the Eocene-Oligocene pole. |
format |
Article in Journal/Newspaper |
author |
Granot, R. Cande, S. C. Stock, J. M. Davey, F. J. Clayton, R. W. |
spellingShingle |
Granot, R. Cande, S. C. Stock, J. M. Davey, F. J. Clayton, R. W. Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences |
author_facet |
Granot, R. Cande, S. C. Stock, J. M. Davey, F. J. Clayton, R. W. |
author_sort |
Granot, R. |
title |
Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences |
title_short |
Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences |
title_full |
Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences |
title_fullStr |
Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences |
title_full_unstemmed |
Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences |
title_sort |
postspreading rifting in the adare basin, antarctica: regional tectonic consequences |
publisher |
American Geophysical Union |
publishDate |
2010 |
url |
https://authors.library.caltech.edu/19709/ https://authors.library.caltech.edu/19709/1/Granot2010p11186Geochem_Geophy_Geosy.pdf https://resolver.caltech.edu/CaltechAUTHORS:20100830-113018904 |
long_lat |
ENVELOPE(170.233,170.233,-71.283,-71.283) ENVELOPE(175.000,175.000,-71.000,-71.000) ENVELOPE(172.500,172.500,-70.033,-70.033) ENVELOPE(170.217,170.217,-72.317,-72.317) |
geographic |
Adare Adare Basin Adare Trough Antarctic Hallett Ross Sea West Antarctica |
geographic_facet |
Adare Adare Basin Adare Trough Antarctic Hallett Ross Sea West Antarctica |
genre |
Antarc* Antarctic Antarctica Ross Sea West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ross Sea West Antarctica |
op_relation |
https://authors.library.caltech.edu/19709/1/Granot2010p11186Geochem_Geophy_Geosy.pdf Granot, R. and Cande, S. C. and Stock, J. M. and Davey, F. J. and Clayton, R. W. (2010) Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences. Geochemistry, Geophysics, Geosystems, 11 . Art. No. Q08005 . ISSN 1525-2027. doi:10.1029/2010GC003105. https://resolver.caltech.edu/CaltechAUTHORS:20100830-113018904 <https://resolver.caltech.edu/CaltechAUTHORS:20100830-113018904> |
op_rights |
other |
op_doi |
https://doi.org/10.1029/2010GC003105 |
container_title |
Geochemistry, Geophysics, Geosystems |
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11 |
container_issue |
8 |
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1766252671995478016 |