Petrology of a transform fault zone and adjacent ridge segments
The Verna Fracture Zone in the North Atlantic (9 to 11° N), which has been identified as a transform fault zone, contains exposures of serpentinized peridotites, while its adjacent ridge segments are floored mainly by typical abyssal ocean ridge basalts. This petrologic contrast correlates with the...
Published in: | Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences |
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Online Access: | http://dx.doi.org/10.1098/rsta.1971.0005 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1971.0005 |
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crroyalsociety:10.1098/rsta.1971.0005 2024-06-02T08:11:32+00:00 Petrology of a transform fault zone and adjacent ridge segments 1971 http://dx.doi.org/10.1098/rsta.1971.0005 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1971.0005 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 268, issue 1192, page 423-441 ISSN 0080-4614 2054-0272 journal-article 1971 crroyalsociety https://doi.org/10.1098/rsta.1971.0005 2024-05-07T14:16:26Z The Verna Fracture Zone in the North Atlantic (9 to 11° N), which has been identified as a transform fault zone, contains exposures of serpentinized peridotites, while its adjacent ridge segments are floored mainly by typical abyssal ocean ridge basalts. This petrologic contrast correlates with the greater frequency of volcanic eruptions along the actively spreading ridge segments compared to the transform fault zone. Where rifting components occur across transform faults, exposures of the deeper zone of oceanic crust may result. The bathymetry of the Verna Fracture Zone suggests that some uplift parallel to the fracture zone as well as rifting led to exposures of deeper rocks. The basalts from the adjacent ridge axes contain ‘xenocrysts’ of plagioclase and olivine and more rarely of chromite. These appear to have a cognate origin, perhaps related to cooling and convection in near surface magma chambers. The basalts from the ridge axes, offset and on opposite sides of the transform fault, have similar features and compositions. The plagioclase peridotites have mineralogical features which indicate equilibration in the plagioclase pyrolite facies, suggesting maximum equilibration depths of around 30 km for a temperature of around 1200 °C. The chemical characteristics of the Vema F.Z. peridotites suggest that they may be undifferentiated mantle, emplaced as a subsolidus hot plastic intrusion or as a crystal mush. The abundance of peridotites and serpentinized peridotites is believed to reflect their abundance in seismic layer three of the oceanic crust. Article in Journal/Newspaper North Atlantic The Royal Society Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences 268 1192 423 441 |
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English |
description |
The Verna Fracture Zone in the North Atlantic (9 to 11° N), which has been identified as a transform fault zone, contains exposures of serpentinized peridotites, while its adjacent ridge segments are floored mainly by typical abyssal ocean ridge basalts. This petrologic contrast correlates with the greater frequency of volcanic eruptions along the actively spreading ridge segments compared to the transform fault zone. Where rifting components occur across transform faults, exposures of the deeper zone of oceanic crust may result. The bathymetry of the Verna Fracture Zone suggests that some uplift parallel to the fracture zone as well as rifting led to exposures of deeper rocks. The basalts from the adjacent ridge axes contain ‘xenocrysts’ of plagioclase and olivine and more rarely of chromite. These appear to have a cognate origin, perhaps related to cooling and convection in near surface magma chambers. The basalts from the ridge axes, offset and on opposite sides of the transform fault, have similar features and compositions. The plagioclase peridotites have mineralogical features which indicate equilibration in the plagioclase pyrolite facies, suggesting maximum equilibration depths of around 30 km for a temperature of around 1200 °C. The chemical characteristics of the Vema F.Z. peridotites suggest that they may be undifferentiated mantle, emplaced as a subsolidus hot plastic intrusion or as a crystal mush. The abundance of peridotites and serpentinized peridotites is believed to reflect their abundance in seismic layer three of the oceanic crust. |
format |
Article in Journal/Newspaper |
title |
Petrology of a transform fault zone and adjacent ridge segments |
spellingShingle |
Petrology of a transform fault zone and adjacent ridge segments |
title_short |
Petrology of a transform fault zone and adjacent ridge segments |
title_full |
Petrology of a transform fault zone and adjacent ridge segments |
title_fullStr |
Petrology of a transform fault zone and adjacent ridge segments |
title_full_unstemmed |
Petrology of a transform fault zone and adjacent ridge segments |
title_sort |
petrology of a transform fault zone and adjacent ridge segments |
publisher |
The Royal Society |
publishDate |
1971 |
url |
http://dx.doi.org/10.1098/rsta.1971.0005 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1971.0005 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences volume 268, issue 1192, page 423-441 ISSN 0080-4614 2054-0272 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rsta.1971.0005 |
container_title |
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences |
container_volume |
268 |
container_issue |
1192 |
container_start_page |
423 |
op_container_end_page |
441 |
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