Barite in omphacite-hosted K-feldspar + quartz poly-crystalline aggregates from the Sulu eclogites and its implications  

作　　者：ZENG LingSen LIU FuLai LIANG FengHua CHEN FangYuan 

机构地区：[1]Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China

出　　处：《Chinese Science Bulletin》2007年第21期2995-3001,共7页

基　　金：Supported by "973" Project from the Ministry of Science and Technology of China (Grant No. 2003CB716504) ;the National Natural Science Foundation of China (Grant No. 40673027)

摘　　要：K-feldspar + quartz polycrystalline aggregates were found as sub-millimeter-size inclusions with a pseudomorph after coesite (?) in omphacites from a number of Sulu eclogites. In these aggregates, round or subhedral barites occur as tiny inclusions in either K-feldspar or quartz. Energy dispersive spectroscopy (EDS) analyses show that these barites have (1) 33.86%―41.12% SO3, 0%―34.65% SrO, and 24.12%―63.55% BaO, (2) seemingly negative linear correlations between SrO and BaO, indicating that they are ideal solid solutions of barite (BaSO4) and celestite (SrSO4), and (3) highly variable Sr/Ba molar ratios ranging from 0 to 2.1. Presence of barites in the Sulu eclogites not only indicates oxidation of the subducting continental crust, but also very limited and restricted fluids pre- sented during exhumation of the Sulu UHP eclogites.K-feldspar ＋ quartz polycrystalline aggregates were found as sub-millimeter-size inclusions with a pseudomorph after coesite （？） in omphacites from a number of Sulu eclogites. In these aggregates, round or subhedral barites occur as tiny inclusions in either K-feldspar or quartz. Energy dispersive spectroscopy （EDS） analyses show that these barites have （1） 33.86%--41.12% SO3, 0%--34.65% SrO, and 24.12%-63.55% BaO, （2） seemingly negative linear correlations between SrO and BaO, indicating that they are ideal solid solutions of barite （BaSO4） and celestite （SrSO4）, and （3） highly variable Sr/Ba molar ratios ranging from 0 to 2.1. Presence of barites in the Sulu eclogites not only indicates oxidation of the subducting continental crust, but also very limited and restricted fluids presented during exhumation of the Sulu UHP eclogites.

关 键 词：重晶石 集料 变质作用 石英石 

分 类 号：TD1[矿业工程—矿山地质测量]