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The prevalence of kilometer-scale heterogeneity in the source region of MORB upper mantle
The source regions of mid-ocean ridge basalts (MORB) are heterogeneous, consisting of chemically and lithologically distinct domains of variable size. Partial melting of such heterogeneous mantle sources gives rise to diverse isotopic compositions of MORB and abyssal peridotites. Variations in radio...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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American Association for the Advancement of Science
2017
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706740/ https://www.ncbi.nlm.nih.gov/pubmed/29202030 http://dx.doi.org/10.1126/sciadv.1701872 |
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author | Liu, Boda Liang, Yan |
author_facet | Liu, Boda Liang, Yan |
author_sort | Liu, Boda |
collection | PubMed |
description | The source regions of mid-ocean ridge basalts (MORB) are heterogeneous, consisting of chemically and lithologically distinct domains of variable size. Partial melting of such heterogeneous mantle sources gives rise to diverse isotopic compositions of MORB and abyssal peridotites. Variations in radiogenic isotope ratios in MORB are attributed to mixing of melts derived from enriched and depleted mantle components. However, melt mixing alone cannot fully account for the difference between the average (143)Nd/(144)Nd in abyssal peridotites and their spatially associated MORB. We show that the more depleted Nd isotope composition in abyssal peridotites is a natural consequence of melt migration–induced mixing or smearing in the melting column. Sub-kilometer scale enriched mantle components or heterogeneities are significantly damped or homogenized in both the residue and erupted melt during their transit through the melting region. Heterogeneities with larger size and higher incompatible trace element abundance are more resistive to the mixing processes. The size-sensitive mixing depends on a parameter called the enrichment strength, which is the product of the heterogeneity size and the ratio between incompatible trace element abundance in the enriched and depleted mantle sources. Observed Nd-Hf isotope variations in MORB and abyssal peridotites can be reproduced if the enrichment strength is 20 to 60 km. These heterogeneities could be on the kilometer scale and have similar isotope ratios to but less incompatible trace element abundances than recycled oceanic crust. |
format | Online Article Text |
id | pubmed-5706740 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | American Association for the Advancement of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-57067402017-11-30 The prevalence of kilometer-scale heterogeneity in the source region of MORB upper mantle Liu, Boda Liang, Yan Sci Adv Research Articles The source regions of mid-ocean ridge basalts (MORB) are heterogeneous, consisting of chemically and lithologically distinct domains of variable size. Partial melting of such heterogeneous mantle sources gives rise to diverse isotopic compositions of MORB and abyssal peridotites. Variations in radiogenic isotope ratios in MORB are attributed to mixing of melts derived from enriched and depleted mantle components. However, melt mixing alone cannot fully account for the difference between the average (143)Nd/(144)Nd in abyssal peridotites and their spatially associated MORB. We show that the more depleted Nd isotope composition in abyssal peridotites is a natural consequence of melt migration–induced mixing or smearing in the melting column. Sub-kilometer scale enriched mantle components or heterogeneities are significantly damped or homogenized in both the residue and erupted melt during their transit through the melting region. Heterogeneities with larger size and higher incompatible trace element abundance are more resistive to the mixing processes. The size-sensitive mixing depends on a parameter called the enrichment strength, which is the product of the heterogeneity size and the ratio between incompatible trace element abundance in the enriched and depleted mantle sources. Observed Nd-Hf isotope variations in MORB and abyssal peridotites can be reproduced if the enrichment strength is 20 to 60 km. These heterogeneities could be on the kilometer scale and have similar isotope ratios to but less incompatible trace element abundances than recycled oceanic crust. American Association for the Advancement of Science 2017-11-22 /pmc/articles/PMC5706740/ /pubmed/29202030 http://dx.doi.org/10.1126/sciadv.1701872 Text en Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). http://creativecommons.org/licenses/by-nc/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license (http://creativecommons.org/licenses/by-nc/4.0/) , which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited. |
spellingShingle | Research Articles Liu, Boda Liang, Yan The prevalence of kilometer-scale heterogeneity in the source region of MORB upper mantle |
title | The prevalence of kilometer-scale heterogeneity in the source region of MORB upper mantle |
title_full | The prevalence of kilometer-scale heterogeneity in the source region of MORB upper mantle |
title_fullStr | The prevalence of kilometer-scale heterogeneity in the source region of MORB upper mantle |
title_full_unstemmed | The prevalence of kilometer-scale heterogeneity in the source region of MORB upper mantle |
title_short | The prevalence of kilometer-scale heterogeneity in the source region of MORB upper mantle |
title_sort | prevalence of kilometer-scale heterogeneity in the source region of morb upper mantle |
topic | Research Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706740/ https://www.ncbi.nlm.nih.gov/pubmed/29202030 http://dx.doi.org/10.1126/sciadv.1701872 |
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