Mélange dehydration and melting beneath South Sandwich Islands arc
Abstract Mechanisms regulating material transfer from subducted slabs to arc magmas remain debated, centered on metasomatized mantle wedge interactions versus mélange mobilization at the slab-mantle interface. The South Sandiwch Islands arc offers a unique setting to distinguish between these models...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2025-02-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-56554-x |
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| author | Yunchao Shu Sune G. Nielsen Veronique Le Roux Danielle Santiago Ramos Jerzy Blusztajn Maureen Auro Phil T. Leat Tristan J. Horner |
| author_facet | Yunchao Shu Sune G. Nielsen Veronique Le Roux Danielle Santiago Ramos Jerzy Blusztajn Maureen Auro Phil T. Leat Tristan J. Horner |
| author_sort | Yunchao Shu |
| collection | DOAJ |
| description | Abstract Mechanisms regulating material transfer from subducted slabs to arc magmas remain debated, centered on metasomatized mantle wedge interactions versus mélange mobilization at the slab-mantle interface. The South Sandiwch Islands arc offers a unique setting to distinguish between these models due to the significant barium isotope contrast between altered oceanic crust and sediments, the latter displaying unusually light barium isotope compositions compared to the global sediment range. Here we show substantial barium isotope variations coupled with invariant strontium isotope ratios in arc lavas, consistent with mélange mobilization beneath the arc. Northern arc lavas display a broader range of barium isotope values than expected from slab inputs, suggesting barium isotope fractionation during slab material transport, potentially driven by phengite-related barium retention within the mélange. Notably, sediments, rather than altered oceanic crust, emerge as the dominant source of barium in arc lavas. While a comparison of barium isotope data from four additional arcs indicates mantle wedge metasomatism remains visible in several cases, mélange mobilization is consistent with available data across all of these subduction zones. |
| format | Article |
| id | doaj-art-6d708ab3a604408eb253d282a1e33a35 |
| institution | Kabale University |
| issn | 2041-1723 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Nature Communications |
| spelling | doaj-art-6d708ab3a604408eb253d282a1e33a352025-02-09T12:44:11ZengNature PortfolioNature Communications2041-17232025-02-0116111310.1038/s41467-025-56554-xMélange dehydration and melting beneath South Sandwich Islands arcYunchao Shu0Sune G. Nielsen1Veronique Le Roux2Danielle Santiago Ramos3Jerzy Blusztajn4Maureen Auro5Phil T. Leat6Tristan J. Horner7NIRVANA (Non-traditional Isotope Research for Various Advanced Novel Applications) Laboratories, Woods Hole Oceanographic InstitutionNIRVANA (Non-traditional Isotope Research for Various Advanced Novel Applications) Laboratories, Woods Hole Oceanographic InstitutionDepartment of Geology and Geophysics, Woods Hole Oceanographic InstitutionNIRVANA (Non-traditional Isotope Research for Various Advanced Novel Applications) Laboratories, Woods Hole Oceanographic InstitutionNIRVANA (Non-traditional Isotope Research for Various Advanced Novel Applications) Laboratories, Woods Hole Oceanographic InstitutionNIRVANA (Non-traditional Isotope Research for Various Advanced Novel Applications) Laboratories, Woods Hole Oceanographic InstitutionBritish Antarctic SurveyNIRVANA (Non-traditional Isotope Research for Various Advanced Novel Applications) Laboratories, Woods Hole Oceanographic InstitutionAbstract Mechanisms regulating material transfer from subducted slabs to arc magmas remain debated, centered on metasomatized mantle wedge interactions versus mélange mobilization at the slab-mantle interface. The South Sandiwch Islands arc offers a unique setting to distinguish between these models due to the significant barium isotope contrast between altered oceanic crust and sediments, the latter displaying unusually light barium isotope compositions compared to the global sediment range. Here we show substantial barium isotope variations coupled with invariant strontium isotope ratios in arc lavas, consistent with mélange mobilization beneath the arc. Northern arc lavas display a broader range of barium isotope values than expected from slab inputs, suggesting barium isotope fractionation during slab material transport, potentially driven by phengite-related barium retention within the mélange. Notably, sediments, rather than altered oceanic crust, emerge as the dominant source of barium in arc lavas. While a comparison of barium isotope data from four additional arcs indicates mantle wedge metasomatism remains visible in several cases, mélange mobilization is consistent with available data across all of these subduction zones.https://doi.org/10.1038/s41467-025-56554-x |
| spellingShingle | Yunchao Shu Sune G. Nielsen Veronique Le Roux Danielle Santiago Ramos Jerzy Blusztajn Maureen Auro Phil T. Leat Tristan J. Horner Mélange dehydration and melting beneath South Sandwich Islands arc Nature Communications |
| title | Mélange dehydration and melting beneath South Sandwich Islands arc |
| title_full | Mélange dehydration and melting beneath South Sandwich Islands arc |
| title_fullStr | Mélange dehydration and melting beneath South Sandwich Islands arc |
| title_full_unstemmed | Mélange dehydration and melting beneath South Sandwich Islands arc |
| title_short | Mélange dehydration and melting beneath South Sandwich Islands arc |
| title_sort | melange dehydration and melting beneath south sandwich islands arc |
| url | https://doi.org/10.1038/s41467-025-56554-x |
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