loading page

Reconstructing the crustal section of the intra-oceanic Caribbean island arc: contraints from the cumulate layered gabbronorites and pyroxenites of the Rio Boba plutonic sequence, northern Dominican Republic
  • +3
  • Javier Escuder-Viruete,
  • Mercedes Castillo-Carrión,
  • Fernando Pérez Valera,
  • Pablo Valverde-Vaquero,
  • Álvaro Rubio Ordónez,
  • Francisco José Fernández
Javier Escuder-Viruete
Instituto Geologico Minero España - CSIC, Instituto Geologico Minero España - CSIC

Corresponding Author:[email protected]

Author Profile
Mercedes Castillo-Carrión
Instituto Geológico y Minero de España, Instituto Geológico y Minero de España
Author Profile
Fernando Pérez Valera
Departamento de Ciencias de la Tierra y del Medio Ambiente, Departamento de Ciencias de la Tierra y del Medio Ambiente
Author Profile
Pablo Valverde-Vaquero
Instituto Geológico y Minero de España - CSIC, Instituto Geológico y Minero de España - CSIC
Author Profile
Álvaro Rubio Ordónez
Departamento de Geología, Departamento de Geología
Author Profile
Francisco José Fernández
Departamento de Geología, Departamento de Geología
Author Profile


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.
Feb 2022Published in Geochemistry, Geophysics, Geosystems volume 23 issue 2. 10.1029/2021GC010101