Evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of South Atlantic MORB
Melt inclusions contained in plagioclase and olivine phenocrysts have been studied in tholeiitic basalts from the Shona ridge-centered hot spot region, South Atlantic Ocean. Two types of primitive melt inclusions exist within a hand sample, Normal-Mid Ocean Ridge Basalt (N-MORB) and Enriched-Mid Oce...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.548.7119 2023-05-15T18:21:12+02:00 Evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of South Atlantic MORB Marco Magnani Toshitsugu Fujii Yuji Orihashi Atsushi Yasuda Takafumi Hirata Alba P. Santo Gloria Vaggelli The Pennsylvania State University CiteSeerX Archives 2005 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.548.7119 http://www.terrapub.co.jp/journals/GJ/pdf/4003/40030277.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.548.7119 http://www.terrapub.co.jp/journals/GJ/pdf/4003/40030277.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.terrapub.co.jp/journals/GJ/pdf/4003/40030277.pdf text 2005 ftciteseerx 2016-01-08T11:24:45Z Melt inclusions contained in plagioclase and olivine phenocrysts have been studied in tholeiitic basalts from the Shona ridge-centered hot spot region, South Atlantic Ocean. Two types of primitive melt inclusions exist within a hand sample, Normal-Mid Ocean Ridge Basalt (N-MORB) and Enriched-Mid Ocean Ridge Basalt (E-MORB) as defined by trace ele-ments. The N-MORB melt inclusions have low (La/Sm)n (0.54–0.72), high Zr/Nb (22–44) and depleted Light Rare Earth Element (LREE) patterns, whereas the E-MORB melt inclusions have high (La/Sm)n (0.79–1.09), low Zr/Nb (12–21) and flat LREE. The composition of melt inclusions has been modified by post-entrapment crystallization of the host phase, but this effect is considered relatively small and does not affect the incompatible trace element ratios. The matrix glasses have mildly E-MORB compositions that lie between the two different types of melt inclusions, suggesting that they are pro-duced by mixing of primary magmas of E-MORB and N-MORB type. The N-MORB primitive melt inclusions are geochemically similar to Indian and other South Atlantic N-MORB in having high Ba/Nb ratios (4–10), but for the first time much more extreme values are found (8–18). The reason for this anomalous enrichment can be related to the presence of old pelagic sediments in a regionally depleted asthenosphere. The melt inclusions of this study display positive anomalies of Sr and Eu, the first time that have been recorded in the Text South Atlantic Ocean Unknown Indian Shona Ridge ENVELOPE(2.750,2.750,-51.000,-51.000) |
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Open Polar |
collection |
Unknown |
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ftciteseerx |
language |
English |
description |
Melt inclusions contained in plagioclase and olivine phenocrysts have been studied in tholeiitic basalts from the Shona ridge-centered hot spot region, South Atlantic Ocean. Two types of primitive melt inclusions exist within a hand sample, Normal-Mid Ocean Ridge Basalt (N-MORB) and Enriched-Mid Ocean Ridge Basalt (E-MORB) as defined by trace ele-ments. The N-MORB melt inclusions have low (La/Sm)n (0.54–0.72), high Zr/Nb (22–44) and depleted Light Rare Earth Element (LREE) patterns, whereas the E-MORB melt inclusions have high (La/Sm)n (0.79–1.09), low Zr/Nb (12–21) and flat LREE. The composition of melt inclusions has been modified by post-entrapment crystallization of the host phase, but this effect is considered relatively small and does not affect the incompatible trace element ratios. The matrix glasses have mildly E-MORB compositions that lie between the two different types of melt inclusions, suggesting that they are pro-duced by mixing of primary magmas of E-MORB and N-MORB type. The N-MORB primitive melt inclusions are geochemically similar to Indian and other South Atlantic N-MORB in having high Ba/Nb ratios (4–10), but for the first time much more extreme values are found (8–18). The reason for this anomalous enrichment can be related to the presence of old pelagic sediments in a regionally depleted asthenosphere. The melt inclusions of this study display positive anomalies of Sr and Eu, the first time that have been recorded in the |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Marco Magnani Toshitsugu Fujii Yuji Orihashi Atsushi Yasuda Takafumi Hirata Alba P. Santo Gloria Vaggelli |
spellingShingle |
Marco Magnani Toshitsugu Fujii Yuji Orihashi Atsushi Yasuda Takafumi Hirata Alba P. Santo Gloria Vaggelli Evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of South Atlantic MORB |
author_facet |
Marco Magnani Toshitsugu Fujii Yuji Orihashi Atsushi Yasuda Takafumi Hirata Alba P. Santo Gloria Vaggelli |
author_sort |
Marco Magnani |
title |
Evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of South Atlantic MORB |
title_short |
Evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of South Atlantic MORB |
title_full |
Evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of South Atlantic MORB |
title_fullStr |
Evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of South Atlantic MORB |
title_full_unstemmed |
Evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of South Atlantic MORB |
title_sort |
evidence of primitive melt heterogeneities preserved in plagioclase-hosted melt inclusions of south atlantic morb |
publishDate |
2005 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.548.7119 http://www.terrapub.co.jp/journals/GJ/pdf/4003/40030277.pdf |
long_lat |
ENVELOPE(2.750,2.750,-51.000,-51.000) |
geographic |
Indian Shona Ridge |
geographic_facet |
Indian Shona Ridge |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
http://www.terrapub.co.jp/journals/GJ/pdf/4003/40030277.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.548.7119 http://www.terrapub.co.jp/journals/GJ/pdf/4003/40030277.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766200342962241536 |