A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea
Marine geophysical surveys over the Scotia Ridge show it to be composed of blocks mainly of continental origin. Major structures found on the blocks are in many cases truncated at block margins and their existence is also inconsistent with the present isolated situation of the blocks. The evidence s...
Published in: | Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences |
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1972
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Online Access: | http://dx.doi.org/10.1098/rsta.1972.0005 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1972.0005 |
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crroyalsociety:10.1098/rsta.1972.0005 2024-09-15T17:47:39+00:00 A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea 1972 http://dx.doi.org/10.1098/rsta.1972.0005 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1972.0005 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences volume 271, issue 1213, page 151-183 ISSN 0080-4614 2054-0272 journal-article 1972 crroyalsociety https://doi.org/10.1098/rsta.1972.0005 2024-07-29T04:23:13Z Marine geophysical surveys over the Scotia Ridge show it to be composed of blocks mainly of continental origin. Major structures found on the blocks are in many cases truncated at block margins and their existence is also inconsistent with the present isolated situation of the blocks. The evidence suggests post-Upper Cretaceous fragmentation of a continuous continental area. Complementary marine geomagnetic studies over the deep water of the Scotia Sea have dated two areas as younger than 22 million years (Ma) and have indicated the direction of spreading in others. A model of present plate motions, based on the magnetic anomalies, explains the active volcanism of the South Sandwich Islands as being caused by consumption of Atlantic crust at the associated trench at a rate of 5.5 cm/year for the past 7 to 8 Ma at least. An Upper Tertiary episode of plate consumption at 5 cm/year at the South Shetland trench, suggested by the magnetic lineations, with a secondary slow extensional widening of Bransfield Strait is used to explain similarly the contemporaneous volcanism of the South Shetland Is. Making the reasonable assumption of a Tertiary formation of the undated parts of the Scotia Sea by spreading in the directions indicated by the magnetic lineations, a tentative reconstruction of the component blocks of the Scotia Ridge is made. The attempt is only partly successful in matching structural patterns across adjacent margins of reconstructed blocks, South Georgia being most obviously wrongly situated. It is suggested that the misfits result from minor errors in the initial assumptions and the modification of structures during fragmentation and drift. South Georgia may have formed on the Atlantic rather than the Pacific side of the compact continental region which is thought to have joined South America and west Antarctica for much of the Mesozoic at least. A Gondwanaland reconstruction is presented which is consistent with the Scotia Ridge reconstruction, in which the Antarctic Peninsula lies alongside the Caird ... Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctica Bransfield Strait Scotia Sea South Sandwich Islands West Antarctica The Royal Society Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences 271 1213 151 183 |
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The Royal Society |
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crroyalsociety |
language |
English |
description |
Marine geophysical surveys over the Scotia Ridge show it to be composed of blocks mainly of continental origin. Major structures found on the blocks are in many cases truncated at block margins and their existence is also inconsistent with the present isolated situation of the blocks. The evidence suggests post-Upper Cretaceous fragmentation of a continuous continental area. Complementary marine geomagnetic studies over the deep water of the Scotia Sea have dated two areas as younger than 22 million years (Ma) and have indicated the direction of spreading in others. A model of present plate motions, based on the magnetic anomalies, explains the active volcanism of the South Sandwich Islands as being caused by consumption of Atlantic crust at the associated trench at a rate of 5.5 cm/year for the past 7 to 8 Ma at least. An Upper Tertiary episode of plate consumption at 5 cm/year at the South Shetland trench, suggested by the magnetic lineations, with a secondary slow extensional widening of Bransfield Strait is used to explain similarly the contemporaneous volcanism of the South Shetland Is. Making the reasonable assumption of a Tertiary formation of the undated parts of the Scotia Sea by spreading in the directions indicated by the magnetic lineations, a tentative reconstruction of the component blocks of the Scotia Ridge is made. The attempt is only partly successful in matching structural patterns across adjacent margins of reconstructed blocks, South Georgia being most obviously wrongly situated. It is suggested that the misfits result from minor errors in the initial assumptions and the modification of structures during fragmentation and drift. South Georgia may have formed on the Atlantic rather than the Pacific side of the compact continental region which is thought to have joined South America and west Antarctica for much of the Mesozoic at least. A Gondwanaland reconstruction is presented which is consistent with the Scotia Ridge reconstruction, in which the Antarctic Peninsula lies alongside the Caird ... |
format |
Article in Journal/Newspaper |
title |
A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea |
spellingShingle |
A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea |
title_short |
A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea |
title_full |
A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea |
title_fullStr |
A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea |
title_full_unstemmed |
A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea |
title_sort |
discussion on volcanism and the structure of the earth - the evolution of the scotia ridge and scotia sea |
publisher |
The Royal Society |
publishDate |
1972 |
url |
http://dx.doi.org/10.1098/rsta.1972.0005 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1972.0005 |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Bransfield Strait Scotia Sea South Sandwich Islands West Antarctica |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Bransfield Strait Scotia Sea South Sandwich Islands West Antarctica |
op_source |
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences volume 271, issue 1213, page 151-183 ISSN 0080-4614 2054-0272 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rsta.1972.0005 |
container_title |
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences |
container_volume |
271 |
container_issue |
1213 |
container_start_page |
151 |
op_container_end_page |
183 |
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1810497108566867968 |