Origin of trondhjemite and albitite at the expense of A-type granite,Aravalli orogen, India:Evidence from new metasomatic replacement fronts

作     者：Parampreet Kaur Naveen Chaudhri Nusrat Eliyas 

作者机构：Centre of Advanced Study in Geology Panjab University 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2019年第10卷第5期

页      面：1891-1913页

核心收录：

学科分类：07[理学] 

主　　题：Albitisation A-type granite Trondhjemite Albitite Alwar complex NW India 

摘      要：The A-type Harsora-Dadikar granites in the Alwar complex of northern Aravalli orogen,NW India provide evidence for subsolidus-requilibration of *** record three new discrete stages of albitisation,producing trondhjemite and albitite sequentially at the expense of original ***-I metasomatism deanorthised the magmatic oligoclase and transformed the grey least-albitised granite to pinkish grey microcline-oligoclase ***-II converted the latter to trondhjemite by replacement of microcline to ***-III metasomatism led to the formation of albitite/albite granite from trondhjemite,where the metasomatically formed oligoclase was replaced by *** stage of metasomatism resulted in nearly complete disappearance of amphibole and biotite,producing a monomineralic rock (albitite),which is consistent with Korzhinskii theory of infiltration *** reaction fronts delineating the Stage-II and Stage-III are sharp and easily discernible by their prominent color differences in Harsora on the outcrop ***,the mineral transformations during three stages are manifested by the differential gains/losses in Na,K,Ca,Rb,Ba,Sr,Fe and *** formation of albite,Cl-rich marialitic scapolite and Cl-rich amphibole in the albitised granites are suggestive of Naand Cl-brines as the metasomatising *** fluid-rock interactions,which can significantly transform the pristine mineralogy of granitoids,should be carefully considered to avoid any misinterpretations about their petrological history.