青藏高原北缘火山岩中辉石岩包体研究  

Pyroxenite Xenolith in the Volcanic Rocks from North Tibet

作　　者：吴才来[1] 杨经绥[1] 李海兵[1] Shi Rendeng 史仁灯[1] 孟繁聪[1] 

机构地区：[1]中国地质科学院地质研究所 [2]Institute of Geology, CAGS,

出　　处：《地球学报》2001年第1期61-66,共6页Acta Geoscientica Sinica

基　　金：国家重点基础研究发展规划项目! (G19980 480 0 );国家自然科学基金! (4973 2 0 70 )

摘　　要：青藏高原北缘可可西里鲸鱼湖、雄鹰台、双泉子火山岩中含有辉石岩包体 ,其主要矿物组成为单斜辉石和斜方辉石。辉石的化学成分与国内外幔源包体 -橄榄岩和辉石岩中的类似 ,与麻粒岩中的明显不同 ;辉石温压计计算结果表明 ,辉石形成的温度为 110 1～ 140 0℃ ,压力为 30× 10 8～ 6 0× 10 8Pa,结合岩浆动力学计算结果 ,推测岩浆的来源深度大于 15 0km ,这与地球物理研究得出本区地下深处存在低速层的结果相吻合。The pyroxenite xenolith in the volcanic rocks from Hohxil, north Tibet, consists of clinopyroxenes and othopyroxenes. Mineral chemically these pyroxenes are similar to mantle enclaves including peridotite and pyroxenite from China and abroad, and different from ones of granulites. The temperatures and pressures of forming pyroxenes are in ranges of 1 101～1 400 ℃(averaged 1 250 ℃) and 30×108～60×108Pa(averaged 46×108Pa)based on the thermobarometer of Mercier(1980), respectively. Combined with magma dynamics we deduced that magma was derived from the mantle with the depth of more than 150 km, which is fit in with geophysical conclusion that showed the low-velocity zone existed in the mantle under 150 km.

关 键 词：青藏高原 矿物化学 可可西里 辉石岩包体 

分 类 号：P574.2[天文地球—矿物学]