The effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of Mid-Ocean Ridge Basalts
Molybdenum (Mo) stable isotopes hold great potential to investigate the processes involved in planetary formation and differentiation. However their use is currently hampered by the lack of understanding of the dominant controls driving mass-dependent fractionations at high temperature. Here we inve...
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ftpubman:oai:pure.mpg.de:item_3547409 2023-11-12T04:07:54+01:00 The effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of Mid-Ocean Ridge Basalts Bezard, R. Fischer-Gödde, M. Hamelin, C. Brennecka, G. Kleine, T. 2016 http://hdl.handle.net/21.11116/0000-000D-D272-5 unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2016.07.056 info:eu-repo/semantics/altIdentifier/pissn/0012-821X http://hdl.handle.net/21.11116/0000-000D-D272-5 Earth and Planetary Science Letters info:eu-repo/semantics/article 2016 ftpubman https://doi.org/10.1016/j.epsl.2016.07.056 2023-10-22T23:47:36Z Molybdenum (Mo) stable isotopes hold great potential to investigate the processes involved in planetary formation and differentiation. However their use is currently hampered by the lack of understanding of the dominant controls driving mass-dependent fractionations at high temperature. Here we investigate the role of magmatic processes and mantle source heterogeneities on the Mo isotope composition of Mid-Ocean Ridges Basalts (MORBs) using samples from two contrasting ridge segments: (1) the extremely fast spreading Pacific-Antarctic (66-41°S) section devoid of plume influence and; (2) the slow spreading Mohns-Knipovich segment (77-71°N) intercepted by the Jan Mayen Plume (71°N). We show that significant variations in Mo stable isotope composition exist in MORBs with δ 98/95 Mo ranging from - 0.24 ‰ to + 0.15 ‰ (relative to NIST SRM3134). The absence of correlation between δ 98/95 Mo and indices of magma differentiation or partial melting suggests a negligible impact of these processes on the isotopic variations observed. On the other hand, the δ 98/95 Mo variations seem to be associated with changes in radiogenic isotope signatures and rare earth element ratios (e.g., (La/Sm) N ), suggesting mantle source heterogeneities as a dominant factor for the δ 98/95 Mo variations amongst MORBs. The heaviest Mo isotope compositions correspond to the most enriched signatures, suggesting that recycled crustal components are isotopically heavy compared to the uncontaminated depleted mantle. The uncontaminated depleted mantle shows slightly sub-chondritic δ 98/95 Mo, which cannot be produced by core formation and, therefore, more likely result from extensive anterior partial melting of the mantle. Consequently, the primitive δ 98/95 Mo composition of the depleted mantle appears overprinted by the effects of both partial melting and crustal recycling. Article in Journal/Newspaper Antarc* Antarctic Jan Mayen Max Planck Society: MPG.PuRe Antarctic Pacific Jan Mayen Earth and Planetary Science Letters 453 171 181 |
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Max Planck Society: MPG.PuRe |
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unknown |
description |
Molybdenum (Mo) stable isotopes hold great potential to investigate the processes involved in planetary formation and differentiation. However their use is currently hampered by the lack of understanding of the dominant controls driving mass-dependent fractionations at high temperature. Here we investigate the role of magmatic processes and mantle source heterogeneities on the Mo isotope composition of Mid-Ocean Ridges Basalts (MORBs) using samples from two contrasting ridge segments: (1) the extremely fast spreading Pacific-Antarctic (66-41°S) section devoid of plume influence and; (2) the slow spreading Mohns-Knipovich segment (77-71°N) intercepted by the Jan Mayen Plume (71°N). We show that significant variations in Mo stable isotope composition exist in MORBs with δ 98/95 Mo ranging from - 0.24 ‰ to + 0.15 ‰ (relative to NIST SRM3134). The absence of correlation between δ 98/95 Mo and indices of magma differentiation or partial melting suggests a negligible impact of these processes on the isotopic variations observed. On the other hand, the δ 98/95 Mo variations seem to be associated with changes in radiogenic isotope signatures and rare earth element ratios (e.g., (La/Sm) N ), suggesting mantle source heterogeneities as a dominant factor for the δ 98/95 Mo variations amongst MORBs. The heaviest Mo isotope compositions correspond to the most enriched signatures, suggesting that recycled crustal components are isotopically heavy compared to the uncontaminated depleted mantle. The uncontaminated depleted mantle shows slightly sub-chondritic δ 98/95 Mo, which cannot be produced by core formation and, therefore, more likely result from extensive anterior partial melting of the mantle. Consequently, the primitive δ 98/95 Mo composition of the depleted mantle appears overprinted by the effects of both partial melting and crustal recycling. |
format |
Article in Journal/Newspaper |
author |
Bezard, R. Fischer-Gödde, M. Hamelin, C. Brennecka, G. Kleine, T. |
spellingShingle |
Bezard, R. Fischer-Gödde, M. Hamelin, C. Brennecka, G. Kleine, T. The effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of Mid-Ocean Ridge Basalts |
author_facet |
Bezard, R. Fischer-Gödde, M. Hamelin, C. Brennecka, G. Kleine, T. |
author_sort |
Bezard, R. |
title |
The effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of Mid-Ocean Ridge Basalts |
title_short |
The effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of Mid-Ocean Ridge Basalts |
title_full |
The effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of Mid-Ocean Ridge Basalts |
title_fullStr |
The effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of Mid-Ocean Ridge Basalts |
title_full_unstemmed |
The effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of Mid-Ocean Ridge Basalts |
title_sort |
effects of magmatic processes and crustal recycling on the molybdenum stable isotopic composition of mid-ocean ridge basalts |
publishDate |
2016 |
url |
http://hdl.handle.net/21.11116/0000-000D-D272-5 |
geographic |
Antarctic Pacific Jan Mayen |
geographic_facet |
Antarctic Pacific Jan Mayen |
genre |
Antarc* Antarctic Jan Mayen |
genre_facet |
Antarc* Antarctic Jan Mayen |
op_source |
Earth and Planetary Science Letters |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2016.07.056 info:eu-repo/semantics/altIdentifier/pissn/0012-821X http://hdl.handle.net/21.11116/0000-000D-D272-5 |
op_doi |
https://doi.org/10.1016/j.epsl.2016.07.056 |
container_title |
Earth and Planetary Science Letters |
container_volume |
453 |
container_start_page |
171 |
op_container_end_page |
181 |
_version_ |
1782328390928302080 |