Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs
Lead isotopic compositions of young volcanic rocks from different tectonic environments have distinctive characteristics. Their differences are evaluated within the framework of global tectonics and mantle differentiation. Ocean island leads are in general more radiogenic than mid-ocean ridge basalt...
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.1980.0224 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1980.0224 |
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crroyalsociety:10.1098/rsta.1980.0224 2024-06-02T08:09:27+00:00 Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs 1980 http://dx.doi.org/10.1098/rsta.1980.0224 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1980.0224 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 297, issue 1431, page 409-445 ISSN 0080-4614 2054-0272 journal-article 1980 crroyalsociety https://doi.org/10.1098/rsta.1980.0224 2024-05-07T14:16:08Z Lead isotopic compositions of young volcanic rocks from different tectonic environments have distinctive characteristics. Their differences are evaluated within the framework of global tectonics and mantle differentiation. Ocean island leads are in general more radiogenic than mid-ocean ridge basalt (m.o.r.b.) leads. They form linear trends on lead isotopic ratio plots. Many of the trends extend toward the field of m.o.r.b. On plots of 207 P b / 204 Pb against 206 Pb / 204 Pb, their slopes are generally close to 0.1. Island arc leads in general are confined between sediment and m.o.r.b. type leads with slopes of ca . 0.30 on a plot of 207 P b / 204 Pb against 206 Pb / 204 Pb. Pb, Sr and Nd isotopic data of Hawaiian volcanics are closely examined. Data from each island support a two-component mixing model. However, there is a lack of full range correlation between islands, indicating heterogeneity in the end members. This mixing model could also be extended to explain data from the Iceland-Reykjanes ridge, and from 45° N on the Atlantic Ridge. The observed chemical and isotopic heterogeneity in young volcanic rocks is considered to be a result of long-term as well as short-term mantle differentiation and mixing. Lead isotopic data from ocean islands are interpreted in terms of mantle evolution models that involve long-term (more than 2 Ga) mantle chemical and isotopic heterogeneity. Incompatible element enriched ‘plume’-type m.o.r.b. have Th/U ratios ca . 3.0 too low and Rb/Sr ratios ca . 0.04 too high to generate the observed 208 Pb and 87 Sr respectively for long periods of time. Elemental fractionation in the mantle must have occurred very recently. This conclusion also applies to mantle sources for ocean island alkali basalts and nephelinites. Depletion of incompatible elements in m.o.r.b. sources is most probably due to continuous extraction of silicate melt and/or fluid phase from the low-velocity zone throughout geological time. Data on Pb isotopes, Sr isotopes and trace elements on volcanic rocks from ... Article in Journal/Newspaper Iceland Ocean Island The Royal Society Reykjanes ENVELOPE(-22.250,-22.250,65.467,65.467) Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences 297 1431 409 445 |
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Open Polar |
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The Royal Society |
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crroyalsociety |
language |
English |
description |
Lead isotopic compositions of young volcanic rocks from different tectonic environments have distinctive characteristics. Their differences are evaluated within the framework of global tectonics and mantle differentiation. Ocean island leads are in general more radiogenic than mid-ocean ridge basalt (m.o.r.b.) leads. They form linear trends on lead isotopic ratio plots. Many of the trends extend toward the field of m.o.r.b. On plots of 207 P b / 204 Pb against 206 Pb / 204 Pb, their slopes are generally close to 0.1. Island arc leads in general are confined between sediment and m.o.r.b. type leads with slopes of ca . 0.30 on a plot of 207 P b / 204 Pb against 206 Pb / 204 Pb. Pb, Sr and Nd isotopic data of Hawaiian volcanics are closely examined. Data from each island support a two-component mixing model. However, there is a lack of full range correlation between islands, indicating heterogeneity in the end members. This mixing model could also be extended to explain data from the Iceland-Reykjanes ridge, and from 45° N on the Atlantic Ridge. The observed chemical and isotopic heterogeneity in young volcanic rocks is considered to be a result of long-term as well as short-term mantle differentiation and mixing. Lead isotopic data from ocean islands are interpreted in terms of mantle evolution models that involve long-term (more than 2 Ga) mantle chemical and isotopic heterogeneity. Incompatible element enriched ‘plume’-type m.o.r.b. have Th/U ratios ca . 3.0 too low and Rb/Sr ratios ca . 0.04 too high to generate the observed 208 Pb and 87 Sr respectively for long periods of time. Elemental fractionation in the mantle must have occurred very recently. This conclusion also applies to mantle sources for ocean island alkali basalts and nephelinites. Depletion of incompatible elements in m.o.r.b. sources is most probably due to continuous extraction of silicate melt and/or fluid phase from the low-velocity zone throughout geological time. Data on Pb isotopes, Sr isotopes and trace elements on volcanic rocks from ... |
format |
Article in Journal/Newspaper |
title |
Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs |
spellingShingle |
Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs |
title_short |
Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs |
title_full |
Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs |
title_fullStr |
Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs |
title_full_unstemmed |
Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs |
title_sort |
lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs |
publisher |
The Royal Society |
publishDate |
1980 |
url |
http://dx.doi.org/10.1098/rsta.1980.0224 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1980.0224 |
long_lat |
ENVELOPE(-22.250,-22.250,65.467,65.467) |
geographic |
Reykjanes |
geographic_facet |
Reykjanes |
genre |
Iceland Ocean Island |
genre_facet |
Iceland Ocean Island |
op_source |
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences volume 297, issue 1431, page 409-445 ISSN 0080-4614 2054-0272 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rsta.1980.0224 |
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Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences |
container_volume |
297 |
container_issue |
1431 |
container_start_page |
409 |
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445 |
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1800755179808620544 |