【摘要】 且干布拉克杂岩体位于库鲁克塔格地块的西南缘,是构造运移到陆壳中的大陆岩石圈地幔顶部的岩块。在862±12Ma期间,该岩体在地幔内经历了复杂的交代作用首先是透辉石交代蛇纹岩;然后是金云母交代蛇纹岩和透辉岩,这些金云母经近地表地质作用后形成了我国规模最大的蛭石矿床;最后是含金云母的碳酸岩岩脉贯入并交代先期形成的各种岩石。研究证明,交代剂应当是碳酸质的碱性硅酸盐熔体或流体,并分异成共轭的两部分这些交代剂普遍具有Ta、Nb、Ti、Zr和Hf的贫化;而且,Nd、Sr、Pb、O、C、H同位素组成普遍具EMⅠ、EMⅡ地幔端元和地壳岩石的特征。由此而证明交代剂主要源自于消减板块中的深海沉积物和在海沟中裹挟的陆源浊积岩。更多还原

【Abstract】 Qieganbulake complex located in the southwest margin ol the Kuluketage massif, as a block mass, was tectonically migrated into continental crust from the top of upper mantle. The complex had undergone complicated metasomatism during 862± 12Ma. First, serpentinites were replaced by diopsides; then, diopsidiles and serpentinites were replaced by phlolopites. which formed the largest scale of roseite deposit in China throuth epigene; finally, phlolopitic carbonatite veins injected and metasomated various rocks formed previously. The studies have proved that metasomating solution may be carbonatic alkali-silicate melt mass or fluid, which was differentiated into two conjugate parters: carbonatic magma and alkali-silicate melt mass or fluid. Nd, Sr, Pb, O, C and H isotopic compositions of metasomating solution, with universally low Ta, Nb, Ti, Zr and Hf, showing characteristics of EM Ⅰ, EM Ⅱ mantle end-member and crust material. All facts indicate that metasomating solution came mainly from deep-sea sediments of the subducting plate and terrigenous turbidites urapped in the sea-floor trench.更多还原