Hydrothermal alteration of chevkinite-(Ce) in the Shuiquangou syenitic intrusion,northern China
会议名称：《中国科学院地质与地球物理研究所2006学术年会》
会议日期：2007年
学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学]
关 键 词：Chevkinite-(Ce) Corona system Hydrothermal alteration Mobilization
摘 要：A rare-earth iron titanosilicate mineral closely associated with amphibole was found in two altered syenite samples from the Shuiquangou syenitic *** on electron microprobe analyses,the mineral is chevkinite-(Ce).The mineral is altered and mantled by a corona of allanite(?)ilmenite(?)titanite(?)epidote(?)*** balance calculations reveal that the former chevkinite was replaced directly by an allanite and ilmenite association (allanite(?)ilmenite zone) in the inner part of the corona *** appears that during the replacement,Si and Ti were immobile,whereas Al,Fe,Mn,Mg and Ca were externally supplied and a proportion of REE and Th were transferred out of the former *** released REE and Th become incorporated in allanite and titanite in the allanite(?)ilmenite(?)titanite mantle where allanite contains higher Nd,Sm and Y but lower La and Ce than that in the allanite(?)ilmenite zone,suggesting that redistribution of these elements took place and the mobility of Nd,Sm and Y is enhanced during hydrothermal alteration.