Reconstructing the crustal section of the intra-oceanic Caribbean island arc: constraints from the cumulate layered gabbronorites and pyroxenites of the Rio Boba plutonic sequence, northern Dominican Republic
| Autor: | Javier Escuder-Viruete, Francisco J. Fernández, Álvaro Rubio Ordónez, Fernando Pérez Valera, Pablo Valverde-Vaquero, Mercedes Castillo-Carrión |
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| Přispěvatelé: | Ministerio de Ciencia e Innovación (España), Universidad de Alicante. Departamento de Ciencias de la Tierra y del Medio Ambiente |
| Rok vydání: | 2022 |
| Předmět: |
Caribbean island
gabbroic cumulate Dominican Republic Estratigrafía Crust Pyroxenites Cretaceous Arc (geometry) Paleontology Sequence (geology) Geophysics supra-subduction zone Gabbronorites Geochemistry and Petrology Section (archaeology) boninite Caribbean plate Rio Boba Plutonic Sequence Intra-Oceanic Caribbean Island Arc Geology Crustal Section pyroxenite geochemistry |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname Scopus RUA. Repositorio Institucional de la Universidad de Alicante Universidad de Alicante (UA) RUO. Repositorio Institucional de la Universidad de Oviedo |
| Popis: | Located in northern Dominican Republic, the Early Cretaceous Rio Boba mafic-ultramafic plutonic sequence constitutes a lower crust section of the Caribbean island arc, made up by gabbroic rocks and subordinate pyroxenite. Modal compositions, mineral chemistry, whole-rock compositions and thermobarometric calculations indicate that pyroxenites and gabbronorites represent a cumulate sequence formed by fractionation of tholeiitic magmas with initially very low H2O content in the lower crust of the arc (0.6-0.8 GPa). Melts evolved along a simplified crystallization sequence of olivine pyroxenes plagioclase Fe-Ti oxides. The magmatic evolution of the Rio Boba sequence and associated supra-crustal Puerca Gorda metavolcanic rocks is multi-stage and involves the generation of magmas from melting of different sources in a supra-subduction zone setting. The first stage included the formation of a highly depleted substrate as result of decompressional melting of a refractory mantle source, represented by a cumulate sequence of LREE-depleted IAT and boninitic gabbronorites and pyroxenites. The second stage involved volumetrically subordinate cumulate troctolites and gabbros, which are not penetratively deformed. The mantle source was refractory and enriched by a LILE-rich hydrous fluid derived from a subducting slab and/or overlying sediments, and possibly by a LREE-rich melt. The third stage is recorded in the upper crust of the arc by the Puerca Gorda ‘normal’ IAT protoliths, which are derived from an N-MORB mantle source enriched with a strong subduction component. This magmatic evolution has implications for unravelling the processes responsible for subduction initiation and subsequent building of the Caribbean island arc. Instituto Geológico y Minero de España, España Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, España Departamento de Geología, Universidad de Oviedo, España |
| Databáze: | OpenAIRE |
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