Multi-isotope and geochemical approach to the magma source and tectonic setting of Proterozoic anorthosite massifs and AnorthositeMangerite-Charnockite-Granite(AMCG)suites  

作　　者：L.A.Elizondo-Pacheco L.A.Solari R.González-Guzmán H.L.He E.Becerra-Torres J.A.Ramírez-Fernández R.Maldonado 

机构地区：[1]Posgrado en Ciencias de la Tierra,Instituto de Geociencias,Universidad Nacional Autónoma de México,Santiago de Querétaro 76230,Mexico [2]Instituto de Geociencias,Universidad Nacional Autónoma de México,Santiago de Querétaro 76230,Mexico [3]Departamento de Geología,División de Ciencias de la Tierra,CICESE,Ensenada 22860,Mexico [4]School of Earth Sciences,Yunnan University,Kunming 650500,PR China [5]Yunnan International Joint Laboratory of Critical Mineral Resource,Kunming 650500,PR China [6]Escuela Nacional de Estudios Superiores Unidad Juriquilla,Universidad Nacional Autónoma de México,Santiago de Querétaro 76230,México [7]Facultad de Ciencias de la Tierra,Universidad Autónoma de Nuevo León,Linares 67700,Mexico [8]Instituto de Geología,Universidad Nacional Autónoma de México,Ciudad de México 04510,Mexico

出　　处：《Geoscience Frontiers》2024年第6期2-21,共20页地学前缘（英文版）

基　　金：LAEP thanks the Consejo Nacional de Humanidades,Ciencias y Tecnologías(CONAHCYT)for granting him a Ph.D.scholarship.;Special thanks to Victor Chashchin,Jean-Clair Duchesne,and Mike Hamilton for sharing valuable articles and published data during the development of datAMCG.This paper contributes to the Conacyt Ciencia de Frontera grant 7351 funded to LAS.HLH is funded by the National Natural Science Foundation of China(Grant No.42272227)。

摘　　要：The occurrence of massif-type anorthosite intrusions is a widespread Proterozoic phenomenon.They are usually associated with gabbroic,charnockitic,and granitic rocks,comprising the so-called anorthositemangerite-charnockite-granite(AMCG)suite.Although these rocks have been extensively studied worldwide,several aspects concerning their formation remain unsettled.Among them,the magma source and the tectonic setting are the most important.To evaluate these issues,we first compiled geochemical and isotopic data of Proterozoic anorthosite massifs and AMCG suites worldwide and stored it in a database named datAMCG.This plethora of data allows us to make some important interpretations.We argue that the wide-ranging multi-isotopic composition of this group of rocks reflects varying proportions of juvenile mantle-derived melts and crustal components.We interpret that the precursor magmas of most massive anorthosite bodies and associated mafic rocks have a mantle-dominated origin.However,we highlight that a crustal component is indispensable to generate these lithologies.Adding variable amounts of this material during succeeding multi-stage assimilation-fractional crystallization(AFC)processes gives these intrusions their typical mantle-crustal hybrid isotopic traits.In contrast,a crustaldominant origin with a complementary mantle component is interpreted for most MCG rocks.In summary,the isotopic information in datAMCG indicates that both sources are necessary to generate AMCG rocks.Therefore,we suggest that hybridized magmas with different mantle-crust proportions originate these rocks.This interpretation might offer a more nuanced and accurate depiction of this phenomenon in future work instead of choosing a single-sourced model as in the past decades.Finally,tectonomagmatic diagrams suggest that the rocks under study were likely generated in a tectonic environment that transitioned between collision and post-collisional extension,sometimes involving subduction-modified mantle sources.This interpretation is supported by

关 键 词：Massif-type anorthosite Anorthosite-granite suite Magmatic sources Hybridized magmas Tectonic setting Post-orogenic extension 

分 类 号：P588.1[天文地球—岩石学] P597[天文地球—地质学] P534.4