新疆北山地区漩涡岭镁铁质-超镁铁质层状岩体岩石学与矿物学研究  

Petrography and Mineralogy of the Xuanwoling Mafic-Ultramafic Layered Intrusion in the Beishan Region, Xinjiang

作　　者：夏昭德[1,2] 王垚[1] 姜常义[1,2] 凌锦兰[1] 夏明哲[1,2] 郭娜欣[1] 

机构地区：[1]长安大学地球科学与资源学院,西安710054 [2]西部矿产资源与地质工程教育部重点实验室,西安710054

出　　处：《地质学报》2013年第4期486-497,共12页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号41102045);中央高校基本科研业务费专项资金(编号CHD2010ZY008);中国地质调查局地质矿产调查评价专项(编号1212011120498和12120113043100)共同资助的成果

摘　　要：位于新疆北山地区的漩涡岭岩体是一堆晶层理发育的镁铁质—超镁铁质层状岩体。岩石类型主要有纯橄岩、橄长岩、橄榄辉长岩和辉长岩等。主要的造岩矿物有橄榄石、辉石、斜长石、铬尖晶石,岩相学特征表明岩浆在演化过程中经历了橄榄石、尖晶石、斜长石、斜方辉石和单斜辉石的分离结晶,结晶次序依次为橄榄石+尖晶石→斜长石→辉石,表明结晶时压力较低。漩涡岭岩体的纯橄岩中橄榄石的Fo高达90.1%,这不同于新疆北部黄山岩带、喀拉通克岩体群以及甘肃金川岩体的橄榄石Fo组成,利用橄榄石最高Fo值估算得到漩涡岭岩体的母岩浆的Mg#为0.73～0.75,岩浆的液相线温度高达1330～1350℃,其岩浆为高温高Mg的苦橄质岩浆,这为塔里木东北部二叠纪地幔柱活动提供了新的证据。The Xuanwoling intrusion, located in the Beishan region in the northeastern Tarim Block, NW China, is one of the mafic-ultramafic intrusions with cumulate texture and rhythmic layering.The rocks in this area contain dunite, troctolite, olivine gabbros and gabbros. Major minerals are olivine,pyroxene, plagioclase, and picotite. Petrographical characters indicate that the Xuanwoling intrusion had undergone fractional crystallization, with crystallization sequence of olivine+spinel, plagioclase and pyroxene, indicating the crystallization pressure was lower than 0.5~0.8GPa.Olivines from this intrusion have high Fo values (up to 90.1%),and this differs from that of ith Kalatongke,Huangshan and Jinchuan intrusions. The Fo molecular of olivine was used to estimates the Mg# values of prarental magma of Xuanwoling intrusion. Th result shows Mg# of the parental magma is 0.73~0.75,and the crystallization temperature of the Xuanwoling intrusion is 1330~1350℃ higher than basalt liquidus temperature about 130℃.Therefore, the magma is picritic magma with high temperature and high MgO, providing new evidence for Permian mantle plume activity in northeastern Tarim.

关 键 词：镁铁质—超镁铁质 岩石学 矿物学 母岩浆 漩涡岭 新疆北山地区 

分 类 号：P57[天文地球—矿物学]