4.5 Article

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

期刊

GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
卷 23, 期 2, 页码 -

出版社

AMER GEOPHYSICAL UNION
DOI: 10.1029/2021GC010101

关键词

pyroxenite; gabbroic cumulate; boninite; supra-subduction zone; geochemistry; Caribbean plate

资金

  1. Ministerio de Ciencia e Innovacion of the Spanish Government [CGL2012-33669/BTE, PID2019-105625RB-C22, MCIN/AEI/10.13039/501100011033, PRX18/00055]

向作者/读者索取更多资源

The Rio Boba mafic-ultramafic plutonic sequence in northern Dominican Republic represents the lower crust of the Caribbean island arc. It is formed by cumulate rocks derived from tholeiitic magmas with low H2O content. The magmatic evolution involves multi-stage processes, including decompressional melting of a refractory mantle source and enrichment by a hydrous fluid derived from a subducting slab and/or overlying sediments.
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 island arc tholeiitic (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 unraveling the processes responsible for subduction initiation and subsequent building of the Caribbean island arc.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.5
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据