Morphology and origin of the Osbourn Trough
The Osbourn Trough is a 900 km long, east-west trending gravity low, visible in satellite altimetry data, which intersects the Tonga Trench at 25°30′S. A recent survey collected gravity, magnetic, echo sounder, and swath bathymetry data on three adjacent, north-south trending ship tracks centered...
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ftcaltechauth:oai:authors.library.caltech.edu:nnh4h-g1h25 2024-09-15T17:44:42+00:00 Morphology and origin of the Osbourn Trough Billen, Magali I. Stock, Joann 2000-06-10 https://doi.org/10.1029/2000JB900035 unknown American Geophysical Union https://doi.org/10.1029/2001JB900020 https://doi.org/10.1029/2000JB900035 oai:authors.library.caltech.edu:nnh4h-g1h25 eprintid:44934 resolverid:CaltechAUTHORS:20140414-140339355 info:eu-repo/semantics/openAccess Other Journal of Geophysical Research B, 105(B6), 13481-13489, (2000-06-10) info:eu-repo/semantics/article 2000 ftcaltechauth https://doi.org/10.1029/2000JB90003510.1029/2001JB900020 2024-08-06T15:34:58Z The Osbourn Trough is a 900 km long, east-west trending gravity low, visible in satellite altimetry data, which intersects the Tonga Trench at 25°30′S. A recent survey collected gravity, magnetic, echo sounder, and swath bathymetry data on three adjacent, north-south trending ship tracks centered on the trough. The linear gravity low is 20–30 mGal less than the regional value and is accompanied by a flat-lying, 200–500 m deep sediment-filled valley. Swath bathymetry images reveal several parallel, east-west trending linear ridges and valleys on either side of the main trough as well as other morphologic features characteristic of relict spreading centers, including a prominent inside corner high and possible pseudo-fault trace. The presence of magnetic anomalies (possibly anomalies 33 and 32) suggests that the seafloor here was formed after the end of the Cretaceous Normal Superchron (anomaly 34). These data support the conclusion that this trough is a spreading center, which stopped spreading in Late Cretaceous time. The existence of this feature has important implications for tectonic reconstructions in this region. The Osbourn Trough could be part of the fossil spreading center between the Pacific Plate and a fragment of the Phoenix Plate, the Bellingshausen Plate. This would require the seafloor between the Osbourn Trough and the Chatham Rise to the south to be a remnant fragment of the Bellingshausen Plate. This remnant may have joined to the Pacific Plate when the Hikurangi Plateau entered the Gondwana subduction zone at the Chatham Rise possibly causing the cessation of spreading on the Osbourn Trough. © 2000 American Geophysical Union. Received July 22, 1999; revised December 16, 1999; accepted January 26, 2000. This research was supported by NSF OPP 9317318 and OCE 9416779. Dallas Abbott, Bruce Luyendyk and Associate Editor Keith Louden provided helpful reviews of this paper. We thank Antarctic Support Associates, the crew and Captain Joe Borkowski of the RVIB Nathaniel B. Palmer, and Suzanne ... Article in Journal/Newspaper Antarc* Antarctic Caltech Authors (California Institute of Technology) |
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Caltech Authors (California Institute of Technology) |
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description |
The Osbourn Trough is a 900 km long, east-west trending gravity low, visible in satellite altimetry data, which intersects the Tonga Trench at 25°30′S. A recent survey collected gravity, magnetic, echo sounder, and swath bathymetry data on three adjacent, north-south trending ship tracks centered on the trough. The linear gravity low is 20–30 mGal less than the regional value and is accompanied by a flat-lying, 200–500 m deep sediment-filled valley. Swath bathymetry images reveal several parallel, east-west trending linear ridges and valleys on either side of the main trough as well as other morphologic features characteristic of relict spreading centers, including a prominent inside corner high and possible pseudo-fault trace. The presence of magnetic anomalies (possibly anomalies 33 and 32) suggests that the seafloor here was formed after the end of the Cretaceous Normal Superchron (anomaly 34). These data support the conclusion that this trough is a spreading center, which stopped spreading in Late Cretaceous time. The existence of this feature has important implications for tectonic reconstructions in this region. The Osbourn Trough could be part of the fossil spreading center between the Pacific Plate and a fragment of the Phoenix Plate, the Bellingshausen Plate. This would require the seafloor between the Osbourn Trough and the Chatham Rise to the south to be a remnant fragment of the Bellingshausen Plate. This remnant may have joined to the Pacific Plate when the Hikurangi Plateau entered the Gondwana subduction zone at the Chatham Rise possibly causing the cessation of spreading on the Osbourn Trough. © 2000 American Geophysical Union. Received July 22, 1999; revised December 16, 1999; accepted January 26, 2000. This research was supported by NSF OPP 9317318 and OCE 9416779. Dallas Abbott, Bruce Luyendyk and Associate Editor Keith Louden provided helpful reviews of this paper. We thank Antarctic Support Associates, the crew and Captain Joe Borkowski of the RVIB Nathaniel B. Palmer, and Suzanne ... |
format |
Article in Journal/Newspaper |
author |
Billen, Magali I. Stock, Joann |
spellingShingle |
Billen, Magali I. Stock, Joann Morphology and origin of the Osbourn Trough |
author_facet |
Billen, Magali I. Stock, Joann |
author_sort |
Billen, Magali I. |
title |
Morphology and origin of the Osbourn Trough |
title_short |
Morphology and origin of the Osbourn Trough |
title_full |
Morphology and origin of the Osbourn Trough |
title_fullStr |
Morphology and origin of the Osbourn Trough |
title_full_unstemmed |
Morphology and origin of the Osbourn Trough |
title_sort |
morphology and origin of the osbourn trough |
publisher |
American Geophysical Union |
publishDate |
2000 |
url |
https://doi.org/10.1029/2000JB900035 |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Journal of Geophysical Research B, 105(B6), 13481-13489, (2000-06-10) |
op_relation |
https://doi.org/10.1029/2001JB900020 https://doi.org/10.1029/2000JB900035 oai:authors.library.caltech.edu:nnh4h-g1h25 eprintid:44934 resolverid:CaltechAUTHORS:20140414-140339355 |
op_rights |
info:eu-repo/semantics/openAccess Other |
op_doi |
https://doi.org/10.1029/2000JB90003510.1029/2001JB900020 |
_version_ |
1810492360314847232 |