地幔岩中不同产状的流体-熔体包裹体及地幔流体交代作用  

STUDY ON FLUID-MELTING INCLUSION IN MANTLE ROCK AND IT’S SIGNIFICANCE FOR MANTLE METASOMATISM

作　　者：谢玉玲[1] 潘琳[1] 徐九华[1] 邱士东[1] 刘玉堂 

机构地区：[1]北京科技大学,北京100083 [2]内蒙古自治区有色地质研究所,内蒙古呼和浩特010010

出　　处：《新疆地质》2005年第1期10-13,i001,共5页Xinjiang Geology

基　　金：国家自然科学基金项目(49972031)资助

摘　　要：地幔捕虏体中存在不同产状的熔体包裹体和各种硅酸盐玻璃相,包括主矿物内部的蠕虫状、长圆形、圆形、不规则状包裹体(I型)、边部的连通的管状包裹体(T型)、主矿物边部和粒间的片状熔融体——“浆胞”(C型),三者可见明显过渡关系,它们是地幔流体交代地幔岩石过程中由交代重熔形成的,是研究地幔流体的特征和地幔交代作用的对象之一.从I型、T型到C型,其成分呈规律变化,其中S、Cu、Ni,K、Na含量呈明显的降低趋势.包裹体中玻璃相的成分较主矿物富Si、Al、S、Cu、Ni、K和Na,再加上CO2包裹体的发现,表明地幔流体的成分富碱金属、Si、Al、S、Cu、Ni和CO2.地幔交代作用可以使交代产物中Si、Al含量升高而形成中酸性岩浆,也可由于硫化物熔体聚集而形成矿浆.不同地区的地幔流体性质可能存在差异,这些不同性质的地幔流体可能与不同类型的地幔成矿作用有关.Fluid-silicate melt inclusions were found in olivine and pyroxene of xenolith. Three occurrences of silicate melt were distinguished under the microscope. They are isolated fluid-melt inclusions (I-type), tube-like fluid-melt inclusion (T-type) at the edge of host mineral and 'magma cell'(C-type) - a dollop of silicate melt at the interval of host minerals. The composition of silicate glass from different occurrences was determined by EPMA and SEM/EDS. From isolated fluid-melt inclusion, tube-like fluid-melt inclusion to 'magma cell' the content of K, Na, S, Cu, Ni decreases because these elements are trapped in during mantle metasomatism. Compared to host minerals, the silicate glass has higher Si, Al, K, Na, S, Cu, Ni. CO2 fluid inclusions were also found in olivine and pyroxene and it is thought that the mantle fluid is rich in Si, Al, K, Na, S, Cu, Ni, CO2. Mantle fluids rich in Si and Al can induce the forming of mid-acid magma through metasomatism and a separate sulfide ore-magma from the silicate melt can congregate.

关 键 词：地幔流体 熔体包裹体 产状 地幔岩 地幔交代作用 地幔捕虏体 流体性质 成矿作用 玻璃相 硅酸盐 蠕虫状 矿物 不规则 熔融体 特征和 成分 Cu Ni Si Al C02 碱金属 CO2 中酸性 硫化物 圆形 I型 T型 C型 含量 Na 岩石 岩浆 

分 类 号：P588.1[天文地球—岩石学]