A heterogeneous subcontinental mantle under the African–Arabian Plate boundary revealed by boron and radiogenic isotopes
Abstract The northern and northwestern margins of the Arabian Plate are a locus of a diffuse and long-lasting (early Miocene to Pleistocene) Na-alkali basaltic volcanism, sourced in the asthenosphere mantle. The upwelling asthenosphere at the Africa–Arabia margin produces very limited magma volumes...
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2021-05-01
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doaj-a82c6ae17d444402b8e00c1e9985c3eb2021-05-30T11:37:29ZengNature Publishing GroupScientific Reports2045-23222021-05-0111111310.1038/s41598-021-90275-7A heterogeneous subcontinental mantle under the African–Arabian Plate boundary revealed by boron and radiogenic isotopesSamuele Agostini0Paolo Di Giuseppe1Piero Manetti2Carlo Doglioni3Sandro Conticelli4Istituto di Geoscienze e Georisorse, Sede Principale di Pisa, Consiglio Nazionale delle RicercheIstituto di Geoscienze e Georisorse, Sede Principale di Pisa, Consiglio Nazionale delle RicercheDipartimento di Scienze della Terra, Università degli Studi di FirenzeDipartimento di Scienze della Terra, Università La Sapienza, RomaDipartimento di Scienze della Terra, Università degli Studi di FirenzeAbstract The northern and northwestern margins of the Arabian Plate are a locus of a diffuse and long-lasting (early Miocene to Pleistocene) Na-alkali basaltic volcanism, sourced in the asthenosphere mantle. The upwelling asthenosphere at the Africa–Arabia margin produces very limited magma volumes in the axial zone. Therefore, portions of hot, fertile mantle continue their eastward migration and are stored at shallower depths under the 100-km thick Arabian lithosphere, which is much thinner than the African one (≈175 km): this causes the occurrence and 20-Ma persistence of magma supply under the study area. Erupted basalts sampled a continuous variation of the mantle source, with a striking correlation among temperature, pressure and isotopic composition shifting between two end members: a 100 km-deep, more depleted source, and a 60 km-deep, more enriched one. In particular, we observed an unusual variation in boron isotopes, which in the oceanic domain does not vary between more depleted and more enriched mantle sources. This study shows that, at least in the considered region, subcontinental mantle is more heterogeneous than the suboceanic one, and able to record for very long times recycling of shallow material.https://doi.org/10.1038/s41598-021-90275-7 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Samuele Agostini Paolo Di Giuseppe Piero Manetti Carlo Doglioni Sandro Conticelli |
spellingShingle |
Samuele Agostini Paolo Di Giuseppe Piero Manetti Carlo Doglioni Sandro Conticelli A heterogeneous subcontinental mantle under the African–Arabian Plate boundary revealed by boron and radiogenic isotopes Scientific Reports |
author_facet |
Samuele Agostini Paolo Di Giuseppe Piero Manetti Carlo Doglioni Sandro Conticelli |
author_sort |
Samuele Agostini |
title |
A heterogeneous subcontinental mantle under the African–Arabian Plate boundary revealed by boron and radiogenic isotopes |
title_short |
A heterogeneous subcontinental mantle under the African–Arabian Plate boundary revealed by boron and radiogenic isotopes |
title_full |
A heterogeneous subcontinental mantle under the African–Arabian Plate boundary revealed by boron and radiogenic isotopes |
title_fullStr |
A heterogeneous subcontinental mantle under the African–Arabian Plate boundary revealed by boron and radiogenic isotopes |
title_full_unstemmed |
A heterogeneous subcontinental mantle under the African–Arabian Plate boundary revealed by boron and radiogenic isotopes |
title_sort |
heterogeneous subcontinental mantle under the african–arabian plate boundary revealed by boron and radiogenic isotopes |
publisher |
Nature Publishing Group |
series |
Scientific Reports |
issn |
2045-2322 |
publishDate |
2021-05-01 |
description |
Abstract The northern and northwestern margins of the Arabian Plate are a locus of a diffuse and long-lasting (early Miocene to Pleistocene) Na-alkali basaltic volcanism, sourced in the asthenosphere mantle. The upwelling asthenosphere at the Africa–Arabia margin produces very limited magma volumes in the axial zone. Therefore, portions of hot, fertile mantle continue their eastward migration and are stored at shallower depths under the 100-km thick Arabian lithosphere, which is much thinner than the African one (≈175 km): this causes the occurrence and 20-Ma persistence of magma supply under the study area. Erupted basalts sampled a continuous variation of the mantle source, with a striking correlation among temperature, pressure and isotopic composition shifting between two end members: a 100 km-deep, more depleted source, and a 60 km-deep, more enriched one. In particular, we observed an unusual variation in boron isotopes, which in the oceanic domain does not vary between more depleted and more enriched mantle sources. This study shows that, at least in the considered region, subcontinental mantle is more heterogeneous than the suboceanic one, and able to record for very long times recycling of shallow material. |
url |
https://doi.org/10.1038/s41598-021-90275-7 |
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