西南天山东德沟异剥钙榴岩化斜长角闪岩中假蓝宝石和富铝尖晶石特征及其地质意义  

Sapphirine and Al-rich Spinel in Rodingitized Amphibolite and the Geological Implications in the Dongdegou,Zhaosu County,Southwestern Tianshan Mountains

作　　者：吴苏[1] 李旭平[1] 孔凡梅[1] 

机构地区：[1]山东科技大学地质科学与工程学院,山东省沉积成矿作用与沉积矿产重点实验室,山东青岛266590

出　　处：《地质论评》2013年第5期823-831,共9页Geological Review

基　　金：国家自然科学基金资助项目(编号40973022);国家973项目(编号2009CB825007)的成果

摘　　要：西南天山昭苏县东德沟中异剥钙榴岩化斜长角闪岩中发现过铝质的假蓝宝石和富铝尖晶石,假蓝宝石的Al2O3含量在64.82％ ～ 66.36％之间,富铝尖晶石的Al2O3含量在65.24％～ 68.54％之间.根据含假蓝宝石和尖晶石的矿物组合和矿物反应结构,利用Theriak-Domino软件,对岩石的变质条件进行模拟,结果表明形成假蓝宝石的峰期温压为700～780℃,0.65～0.75 GPa,达到了麻粒岩相的变质条件,峰期变质反应为：角闪石（Am）＋尖晶石（Spl）＋钙长石（An）=绿泥石（Chl）＋透辉石（Di）＋假蓝宝石（Spr）,岩石在异剥钙榴岩化之前经历了一次高温富Al（熔）流体的交代进变质作用.含假蓝宝石麻粒岩相变质作用的出现为西南天山俯冲上板片岩石复杂的变质作用过程又增添了新的内容,具有重要的地质意义.Peraluminous sapphirine and Al-rich spinel were discovered in rodingitized amphibolite in the Dongdegou, Zhaosu County, southwestern Tianshan Mountains, the content of A12 03 in sapphirine is between 64. 82% and 66.36%, in Al-rieh spinel between 65.24% and 68.54%. According to the sapphirine-bearing mineral assemblages and mineral reaction textures, using the Theriak--Domino software, the metamorphic process of the bulk rock was simulated. The results showed that the peak temperature--pressure conditions were 700 -780 ~C ,0. 65 -0. 75 GPa, reaching granulite facies metamorphic conditions. The peak metamorphic reaction is： amphibole （Am） ＋ spinel （Spl） ＋ anorthite （An） = chlorite （Chl） ＋ diopside （Di） ＋ sapphirine （Spr）. Rocks experienced an Al-rich fluid/melt metasomatic metamorphism of high temperature. The occurrence of sapphirine-bearing granulite facies rocks adds new insight for the complicated metamorphic processes of rocks in supra subduction zone of the southwestern Tianshan Mountains, showing important geological implications.

关 键 词：假蓝宝石 异剥钙榴岩化斜长角闪岩 麻粒岩相变质 西南天山 

分 类 号：P588.3[天文地球—岩石学]