鲁西中生代辉长-闪长岩中辉石岩捕虏体的岩石成因

鲁西中生代辉长-闪长岩中包含有变晶结构和堆积结构两种类型辉石岩类捕虏体,它们的矿物化学和岩石地球化学特征可同中国东部新生代玄武岩中的辉石岩类包体相对比.它们代表了上地幔两次岩浆底侵事件的产物.辉石岩类捕虏体母岩浆来自于含有陆壳物质的软流圈及其上部岩石圈地幔的部分熔融.辉石岩类捕虏体是由该母岩浆高压分离结晶堆积的产物.辉石岩的母岩浆在上地幔的运移是引起鲁西中生代岩石圈地幔富硅质交代作用的主要因素.

Petrogenesis of pyroxenite xenoliths in Mesozoic gabbro-diorite from western Shandong Province, China

Two types of pyroxenite xenoliths with crystalloblastic and accumulational textures can be found in Mesozoic gabbro-diorite from western Shandong Province. The mineral chemistry and petro-geochemical characteristics of the xenoliths are similar to those of pyroxenite inclusions in Cenozoic basalts from eastern China. The pyroxenite xenoliths could be resulted from two periods of magmatic underplating. The parental magma for pyroxenite xenoliths could be derived from the partial melting of the asthenosphere with continental crust material involvement and of the upper lithospheric mantle. The pyroxenite xenoliths could be accumulates of the high-pressure fractional crystallization of the parental magma. The flow of pyroxenitic parental magma in the upper mantle should be a major factor resulting in silica-rich metasomatism in the Mesozoic lithospheric mantle in western Shandong Province.