Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data
Interpretations of multichannel seismic (MCS) reflection and potential field data suggest that some prominent gravity anomalies in the Bellingshausen Sea are associated with plate boundaries that were active during the Late Cretaceous and early Tertiary. Between 83degrees and 93degreesW, a belt of n...
Published in: | Journal of Geophysical Research: Solid Earth |
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American Geophysical Union
2002
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Online Access: | http://nora.nerc.ac.uk/id/eprint/13260/ http://www.agu.org/journals/jb/jb0212/2002JB001897/2002JB001897.pdf |
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ftnerc:oai:nora.nerc.ac.uk:13260 2023-05-15T13:45:11+02:00 Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data Cunningham, Alex P. Larter, Robert D. Barker, Peter F. Gohl, Karsten Nitsche, Frank O. 2002 http://nora.nerc.ac.uk/id/eprint/13260/ http://www.agu.org/journals/jb/jb0212/2002JB001897/2002JB001897.pdf unknown American Geophysical Union Cunningham, Alex P.; Larter, Robert D. orcid:0000-0002-8414-7389 Barker, Peter F.; Gohl, Karsten; Nitsche, Frank O. 2002 Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data. Journal of Geophysical Research, 107 (B12), 2346. 20, pp. https://doi.org/10.1029/2002JB001897 <https://doi.org/10.1029/2002JB001897> Earth Sciences Publication - Article PeerReviewed 2002 ftnerc https://doi.org/10.1029/2002JB001897 2023-02-04T19:28:30Z Interpretations of multichannel seismic (MCS) reflection and potential field data suggest that some prominent gravity anomalies in the Bellingshausen Sea are associated with plate boundaries that were active during the Late Cretaceous and early Tertiary. Between 83degrees and 93degreesW, a belt of negative anomalies extends along the West Antarctic continental slope, which we term the continental slope gravity anomaly (CSGA). MCS profiles show that the CSGA coincides with an acoustically opaque structural high imaged beneath the lower slope. We interpret this structure as the upper part of an accretionary prism which formed during southward subduction of the Phoenix and Charcot plates, before Chatham Rise separated from West Antarctica. MCS profiles crossing the same margin to the northeast show no evidence of an extensive buried accretionary prism, but instead reveal an abrupt northeastward steepening of the continental slope near 78degreesW. We attribute this change in tectonic style, at least in part, to subduction erosion resulting from subduction of rough oceanic basement which formed at the Antarctic-Phoenix ridge after an abrupt decrease in spreading rate at chron 23r (52 Ma). Near 95degreesW, the Bellingshausen gravity anomaly (BGA) consists of a prominent low-high gravity couple which crosses the West Antarctic continental shelf, slope, and rise. The BGA corresponds to a buried asymmetric basement trough, where Cretaceous oceanic basement dips beneath more elevated basement to the east. The trough probably formed after subduction of Charcot plate ocean floor stalled at the nearby Antarctic Peninsula margin, near the end of the Cretaceous Normal Superchron. Ocean floor to the east of the BGA became attached to the Antarctic Peninsula, and the BGA trough subsequently accommodated a small amount of convergent motion between the Antarctic Peninsula and the ocean floor to the west (initially part of the Marie Byrd Land plate and later part of the Bellingshausen plate). Tectonism probably ceased at the BGAat ... Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctica Bellingshausen Sea Marie Byrd Land West Antarctica Natural Environment Research Council: NERC Open Research Archive Antarctic Antarctic Peninsula Bellingshausen Sea Byrd Charcot ENVELOPE(139.017,139.017,-69.367,-69.367) Marie Byrd Land ENVELOPE(-130.000,-130.000,-78.000,-78.000) Pacific The Antarctic West Antarctica Journal of Geophysical Research: Solid Earth 107 B12 EPM 6-1 EPM 6-20 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Cunningham, Alex P. Larter, Robert D. Barker, Peter F. Gohl, Karsten Nitsche, Frank O. Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data |
topic_facet |
Earth Sciences |
description |
Interpretations of multichannel seismic (MCS) reflection and potential field data suggest that some prominent gravity anomalies in the Bellingshausen Sea are associated with plate boundaries that were active during the Late Cretaceous and early Tertiary. Between 83degrees and 93degreesW, a belt of negative anomalies extends along the West Antarctic continental slope, which we term the continental slope gravity anomaly (CSGA). MCS profiles show that the CSGA coincides with an acoustically opaque structural high imaged beneath the lower slope. We interpret this structure as the upper part of an accretionary prism which formed during southward subduction of the Phoenix and Charcot plates, before Chatham Rise separated from West Antarctica. MCS profiles crossing the same margin to the northeast show no evidence of an extensive buried accretionary prism, but instead reveal an abrupt northeastward steepening of the continental slope near 78degreesW. We attribute this change in tectonic style, at least in part, to subduction erosion resulting from subduction of rough oceanic basement which formed at the Antarctic-Phoenix ridge after an abrupt decrease in spreading rate at chron 23r (52 Ma). Near 95degreesW, the Bellingshausen gravity anomaly (BGA) consists of a prominent low-high gravity couple which crosses the West Antarctic continental shelf, slope, and rise. The BGA corresponds to a buried asymmetric basement trough, where Cretaceous oceanic basement dips beneath more elevated basement to the east. The trough probably formed after subduction of Charcot plate ocean floor stalled at the nearby Antarctic Peninsula margin, near the end of the Cretaceous Normal Superchron. Ocean floor to the east of the BGA became attached to the Antarctic Peninsula, and the BGA trough subsequently accommodated a small amount of convergent motion between the Antarctic Peninsula and the ocean floor to the west (initially part of the Marie Byrd Land plate and later part of the Bellingshausen plate). Tectonism probably ceased at the BGAat ... |
format |
Article in Journal/Newspaper |
author |
Cunningham, Alex P. Larter, Robert D. Barker, Peter F. Gohl, Karsten Nitsche, Frank O. |
author_facet |
Cunningham, Alex P. Larter, Robert D. Barker, Peter F. Gohl, Karsten Nitsche, Frank O. |
author_sort |
Cunningham, Alex P. |
title |
Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data |
title_short |
Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data |
title_full |
Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data |
title_fullStr |
Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data |
title_full_unstemmed |
Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data |
title_sort |
tectonic evolution of the pacific margin of antarctica 2. structure of late cretaceous-early tertiary plate boundaries in the bellingshausen sea from seismic reflection and gravity data |
publisher |
American Geophysical Union |
publishDate |
2002 |
url |
http://nora.nerc.ac.uk/id/eprint/13260/ http://www.agu.org/journals/jb/jb0212/2002JB001897/2002JB001897.pdf |
long_lat |
ENVELOPE(139.017,139.017,-69.367,-69.367) ENVELOPE(-130.000,-130.000,-78.000,-78.000) |
geographic |
Antarctic Antarctic Peninsula Bellingshausen Sea Byrd Charcot Marie Byrd Land Pacific The Antarctic West Antarctica |
geographic_facet |
Antarctic Antarctic Peninsula Bellingshausen Sea Byrd Charcot Marie Byrd Land Pacific The Antarctic West Antarctica |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Bellingshausen Sea Marie Byrd Land West Antarctica |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Bellingshausen Sea Marie Byrd Land West Antarctica |
op_relation |
Cunningham, Alex P.; Larter, Robert D. orcid:0000-0002-8414-7389 Barker, Peter F.; Gohl, Karsten; Nitsche, Frank O. 2002 Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data. Journal of Geophysical Research, 107 (B12), 2346. 20, pp. https://doi.org/10.1029/2002JB001897 <https://doi.org/10.1029/2002JB001897> |
op_doi |
https://doi.org/10.1029/2002JB001897 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
107 |
container_issue |
B12 |
container_start_page |
EPM 6-1 |
op_container_end_page |
EPM 6-20 |
_version_ |
1766215423930400768 |