新疆北山地区红石山岩体橄榄石与铬尖晶石成分特征及成因意义  

The Olivine and Chrome Spinel Composition Characteristics of the Hongshishan Mafic-Ultramafic Intrusion in the Beishan Area,Xinjiangand its Genesis

作　　者：夏昭德[1,2] 夏明哲[1,2] 范亚洲[1] 

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

出　　处：《新疆地质》2015年第1期33-40,共8页Xinjiang Geology

基　　金：国家自然科学基金(41302070;41102045);中国地质调查局国土资源大调查(1212011120498;12120113043100);中央高校基本科研业务费专项(2014G1271066)联合资助

摘　　要：红石山镁铁质-超镁铁质岩体，位于塔里木板块东北部的新疆北山地区，岩体平面为长条状，出露面积大于100 km2。岩体的堆晶韵律和堆晶旋回发育，属典型的层状岩体，每个旋回之间为突变接触关系，旋回内部为迅速或渐变过渡关系。岩石类型丰富，主要有纯橄岩、（含长）单辉橄榄岩、橄长岩、橄榄辉长岩、辉长岩和少量辉石岩。橄榄石和铬尖晶石是重要的早期结晶矿物。通过电子探针分析证明：橄榄石的Fo值为76~90.2，总体上随基性程度的降低，Fo降低。铬尖晶石Cr#为54~69，变化范围较小，落于典型层状岩体的铬尖晶石组成范围。模拟计算表明，形成红石山岩体的地幔部分熔融程度高（17.29%~18.92%，平均为18.41%）、原生岩浆为高温（1290℃~1330℃）、高镁（MgO=13.63%）的苦橄质岩浆，这为塔里木二叠纪地幔柱活动提供了新的证据。s：The Hongshishan mafic-ultramafic intrusion,located in the Beishan terrane,northeastern Tarim Block,NW China,is elongated plane and the exposed area over 100 km2.The intrusion belongs to layered intrusion with cumulate tex-ture and rhythmic layering,and the contact relationships of each cycle is mutation and the internal cycle is a quick or grad-ual transition.The Hongshishan intrusion is composed of dunite,clinopyroxene peridotite, troctolite,olivine gabbros,gab-bros and minor pyroxenite. and the main minerals are olivine,pyroxene and plagioclase.Olivine and chromites are impor-tant early crystallization of minerals. The electron microprobe analysis proved that the Fo value of olivine is 76 to 90.2 reduced from dunite to gabbro The Cr # of Chromites is 54 to 69,the range is small,belong to the typical composition range for chromites in layered intrusions. Simulations show that the degree of mantle partial melting is high up to 17.29%~18.92%（an average of 18.41%） and the primary magma is high temperature （1 290℃~1 330℃） and high magnesium （MgO=13.63%） of Picritic magma,providing the new evidence for Tarim Permian mantle plume activity.

关 键 词：红石山 橄榄石 铬尖晶石 地幔部分熔融 苦橄质岩浆 

分 类 号：P578.46[天文地球—矿物学] P578.942[天文地球—地质学]