北秦岭晋宁期中酸性侵入岩带地球化学特征与构造环境

北秦岭侵入岩带中的中酸性侵入岩主要形成于晋宁旋回的中晚期阶段。主要岩石类型包括辉石闪长岩、闪长岩、石英闪长岩、英云闪长岩、花岗闪长岩、斜长花岗岩、花岗岩和钾长花岗岩。岩石化学、稀土元素和微量元素地球化学研究证明,这些岩石主要形成于B型俯冲和碰撞造山的构造环境中,而钾长花岗岩形成于后造山的伸展阶段。据此,该侵入岩带揭示了北秦岭褶皱带在晋宁旋回中晚期阶段的演化过程。

GEOCHEMISTRY FEATURES AND THE TECTONIC SETTING OF INTERMEDIATE-ACID INTRUSIVE ROCKS OF THE JINNING PERIOD IN THE NORTH QINLING

The intermediate-acid intrusive rocks which are situated in the North Qinling, were shaped in the middle-later period of Jinning cycte. The main rock type includes pyroxiere diorites, diorite, quartz diorites, guartz mica diorites, grano diorites, plagio granites, granites and potash feldspoar granites. Based on studies of rock chemistry, rare earth elements and micre elements, it is proved that these rocks were shaped in the tectonic setting of B-type subduction zone and collision zone. The potash feldspoar granite was formed in the post-orogenic extensional stage. In view of the above, this intrusive rock zone reveals the evolution process of the middle-later period of the Jinning cycte in the North Qinling folding belt.