Ophiolite hosted chromitite formed by supra-subduction zone peridotite–plume interaction  

作　　者：Júlia Farré-de-Pablo Joaquín A.Proenza JoséMaría González-Jiménez Thomas Aiglsperger Antonio Garcia-Casco Javier Escuder-Viruete Vanessa Colás Francisco Longo 

机构地区：[1]Departament de Mineralogia,Petrologia i Geologia Aplicada,Universitat de Barcelona,C/Martíi Franques,s/n,08028,Barcelona,Spain [2]Departamento de Mineraloga y Petrologa,Universidad de Granada,Facultad de Ciencias,Fuentenueva s/n,18002,Granada,Spain [3]Department of Civil Engineering and Natural Resources,LuleåUniversity of Technology,SE 97187,Luleå,Sweden [4]Instituto Andaluz de Ciencias de la Tierra(CSIC-UGR),Avda.de las Palmeras 4,E-18100,Armilla,Granada,Spain [5]Instituto Geologico y Minero de Espana,C/La Calera 1,Tres Cantos,28760,Madrid,Spain [6]Instituto de Geología,Universidad Nacional Autonoma de México,Ciudad Universitaria,04510,Ciudad de México,Mexico [7]Facultad de Ingeniería,Universidad Catòlica de Cibao,La Vega,Dominican Republic

出　　处：《Geoscience Frontiers》2020年第6期2083-2102,共20页地学前缘（英文版）

基　　金：provided by the Fondo Europeo de Desarrollo Regional(FEDER)Funds;the Spanish Project CGL2015-65824 granted by the Spanish Ministerio de Economía y Competitividad(MINECO)to JAP and RTI2018-099157-A-I00 Ministerio de Ciencia;Innovacion y Universidades(MICINN)to JMGJ.Additional funding was obtained from the Ramon y Cajal Fellowship RYC-2015-17596 to JMGJ(sponsored by MICINN);the Ph.D.grant BES-2016-076887 to JFdP(sponsored by MINECO);the Mexican research programs Ciencia Basica(A1-S14574);sponsored by the Consejo Nacional de Ciencia y Tecnología(CONACYT)from Mexico,and the Programa de Apoyo a Proyectos de Investigacion e Innovacion tecnologica(IA-101419);sponsored by the UNAM.Additional support was provided by the University of Barcelona and University of Granada,Spain。

摘　　要：Chromitite bodies hosted in peridotites typical of suboceanic mantle(s.l.ophiolitic)are found in the northern and central part of the Loma Caribe peridotite,in the Cordillera Central of the Dominican Republic.These chromitites are massive pods of small size(less than a few meters across)and veins that intrude both dunite and harzburgite.Compositionally,they are high-Cr chromitites[Cr#=Cr/(Cr+Al)atomic ratio=0.71-0.83]singularly enriched in TiO2(up to 1.25 wt.%),Fe2 O3(2.77-9.16 wt.%)as well as some trace elements(Ga,V,Co,Mn,and Zn)and PGE(up to 4548 ppb in whole-rock).This geochemical signature is unknown for chromitites hosted in oceanic upper mantle but akin to those chromites crystallized from mantle plume derived melts.Noteworthy,the melt estimated to be in equilibrium with such chromite from the Loma Caribe chromitites is similar to basalts derived from different source regions of a heterogeneous Caribbean mantle plume.This mantle plume is responsible for the formation of the Caribbean Large Igneous Province(CLIP).Dolerite dykes with back-arc basin basalt(BABB)and enriched mid-ocean ridge basalt(E-MORB)affinities commonly intrude the Loma Caribe peridotite,and are interpreted as evidence of the impact that the Caribbean plume had in the off-axis magmatism of the back-arc basin,developed after the Caribbean island-arc extension in the Late Cretaceous.We propose a model in which chromitites were formed in the shallow portion of the back-arc mantle as a result of the metasomatic reaction between the supra-subduction zone(SSZ)peridotites and upwelling plume-related melts.

关 键 词：CHROMITITE OPHIOLITE PLUME MANTLE Back-arc basin Dominican Republic 

分 类 号：P618.3[天文地球—矿床学] P587[天文地球—地质学]