【摘要】 研究区内有两类密切共生的活动陆缘型幔源侵入岩组合，它们分属拉斑系列和钙碱系列。这两个系列的侵入岩存在系统的化学差异，而且在高位岩浆房中普遍经历了镁铁矿物的分离结晶作用。拉斑系列与钙碱系列均具有板块会聚边缘幔源岩浆的地球化学特征。它们均不同程度地富集大离子亲石元素而贫高场强元素、过渡族元素和重稀土元素。地球化学研究证明，这两个系列的岩浆起源于同一贫化型地幔源区，源岩类型为尖晶石橄榄岩。大离子亲石元素的富集应归因于消减板块的脱水作用或熔融作用。两个系列间的化学差异起因于拉斑系列的熔融程度高于钙碱系列。它们均为晋宁期古秦岭洋盆闭合过程的产物更多还原

【Abstract】 In the study area there exist two types of closely associated active epicontinental mantle-derived intrusive assemblages, belonging to tholeiite series and calc-alkaline series respectively. Intrusive rocks of the two series show systematic chemical differences, and generally experienced fractional crystallization of mafic minerals at the high magmatic chamber. Both the tholeiite series and the calc-alkaline series exhibit geochemical characteristics of mantle-derived magma along the margin of plate convergence, and are in different degrees enriched in large-ion lithophile elements and impoverished in high field strong elements, transitional elements and heavy rare earth elements. Geochemical studies show that magma of these two series originated from the same impoverished mantle source, with the source rock being spinel peridotite. The enrichment of large-ion lithophile elements should be attributed to the devatering or melting of the subducting plate. The chemical differences between these two series resulted from the higher melting degree of the tholeiite series than that of the calc-alkaline series. They were both formed during the closing process of the Qinling paleooceanic basin in Jinning period.更多还原