Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous
Multichannel seismic reflection, gravity, magnetic, and bathymetric investigations were made along five latitudinal profiles from the eastern shelf of India of the Andaman shelf and four NW-SE profiles in the Western Basin off Madras (seismics on three latitudinal profiles) in the Bay of Bengal. The...
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American Geophysical Union
1997
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ftnio:oai:dsr.nio.org:2264/2055 2023-05-15T13:59:28+02:00 Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous Rao, D.G. Krishna, K.S. Sar, D. 1997 http://drs.nio.org/drs/handle/2264/2055 en eng American Geophysical Union Copyright [1997]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository. geophysical data continental shelves fracture zones plate tectonics anomalies crustal accretion cretaceous sedimentation Journal Article 1997 ftnio 2012-08-25T20:06:34Z Multichannel seismic reflection, gravity, magnetic, and bathymetric investigations were made along five latitudinal profiles from the eastern shelf of India of the Andaman shelf and four NW-SE profiles in the Western Basin off Madras (seismics on three latitudinal profiles) in the Bay of Bengal. The trend of the fracture zones, the locations of the magnetic chron 34, and the Cretaceous Magnetic Quiet Zone suggest that Greater India separated from Antarctica after a period of transform motion in the early Cretaceous, that is, about polarity chron MO (120 Ma) and drifted northwestward. Negative gravity annomalies are associated with basement rises including the 85 degrees E Ridge between the continental margin of India and the Ninetyeast Ridge. magnetic rever-sals and northweard trend of the 85 degrees E Ridge support a hotspot origin of the ridge and its emplacement most likely after the Cretaceous quiet period. Juxtaposition of high - amplitude hyperbolic reflections, down-faulted continental blocks buried under thick sediments, and associated gravity and magnetic anomalies mark the bounday between continental and oceanic rocks at the foot of continental slope, about 80 km seaward of the present continental shelf edge. Eight seismic sequences, as thick as 8.5 km, overlie the early Cretaceous oceanic basement and include four unconformities (lower Eocene, upper Oligocene, upper Miocene, and upper Pleistocene) which have been correlated to the major geologic/tectonic events. We also interpret the late Cretaceous/early Tertiary features on the eastern flank of the buried 85 degrees E Ridge as carbonate reefs. The observation of steep subduction of older (cold) Indian plate beneath the Burmese plate near the Andaman Islands suggests the Sunda Arc in this region as low to intermediate stress subduction zone Article in Journal/Newspaper Antarc* Antarctica National Institute of Oceanography, India: Digital Repository Service (DRS@nio) Indian Western Basin Sunda ENVELOPE(-6.982,-6.982,62.205,62.205) |
institution |
Open Polar |
collection |
National Institute of Oceanography, India: Digital Repository Service (DRS@nio) |
op_collection_id |
ftnio |
language |
English |
topic |
geophysical data continental shelves fracture zones plate tectonics anomalies crustal accretion cretaceous sedimentation |
spellingShingle |
geophysical data continental shelves fracture zones plate tectonics anomalies crustal accretion cretaceous sedimentation Rao, D.G. Krishna, K.S. Sar, D. Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous |
topic_facet |
geophysical data continental shelves fracture zones plate tectonics anomalies crustal accretion cretaceous sedimentation |
description |
Multichannel seismic reflection, gravity, magnetic, and bathymetric investigations were made along five latitudinal profiles from the eastern shelf of India of the Andaman shelf and four NW-SE profiles in the Western Basin off Madras (seismics on three latitudinal profiles) in the Bay of Bengal. The trend of the fracture zones, the locations of the magnetic chron 34, and the Cretaceous Magnetic Quiet Zone suggest that Greater India separated from Antarctica after a period of transform motion in the early Cretaceous, that is, about polarity chron MO (120 Ma) and drifted northwestward. Negative gravity annomalies are associated with basement rises including the 85 degrees E Ridge between the continental margin of India and the Ninetyeast Ridge. magnetic rever-sals and northweard trend of the 85 degrees E Ridge support a hotspot origin of the ridge and its emplacement most likely after the Cretaceous quiet period. Juxtaposition of high - amplitude hyperbolic reflections, down-faulted continental blocks buried under thick sediments, and associated gravity and magnetic anomalies mark the bounday between continental and oceanic rocks at the foot of continental slope, about 80 km seaward of the present continental shelf edge. Eight seismic sequences, as thick as 8.5 km, overlie the early Cretaceous oceanic basement and include four unconformities (lower Eocene, upper Oligocene, upper Miocene, and upper Pleistocene) which have been correlated to the major geologic/tectonic events. We also interpret the late Cretaceous/early Tertiary features on the eastern flank of the buried 85 degrees E Ridge as carbonate reefs. The observation of steep subduction of older (cold) Indian plate beneath the Burmese plate near the Andaman Islands suggests the Sunda Arc in this region as low to intermediate stress subduction zone |
format |
Article in Journal/Newspaper |
author |
Rao, D.G. Krishna, K.S. Sar, D. |
author_facet |
Rao, D.G. Krishna, K.S. Sar, D. |
author_sort |
Rao, D.G. |
title |
Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous |
title_short |
Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous |
title_full |
Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous |
title_fullStr |
Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous |
title_full_unstemmed |
Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous |
title_sort |
curstal evolution and sedimentation history of the bay of bengal since the cretaceous |
publisher |
American Geophysical Union |
publishDate |
1997 |
url |
http://drs.nio.org/drs/handle/2264/2055 |
long_lat |
ENVELOPE(-6.982,-6.982,62.205,62.205) |
geographic |
Indian Western Basin Sunda |
geographic_facet |
Indian Western Basin Sunda |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_rights |
Copyright [1997]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository. |
_version_ |
1766268023392436224 |