武当地块基性岩度群岩石地球化学特征及其大地构造意义

南秦岭构造带武当地块核部的基性岩席群，是在古生代地幔底侵作用导致地壳伸展过程中岩浆沿主拆离面及基底变质岩群内次一级滑脱面侵位形成。岩席群岩石地球化学特征的研究表明，其主元素、微量元素及稀土元素地球化学与勉略缝合带发育的蛇绿岩组合中的辉绿岩和大洋玄武岩之岩石地球化学特点相似，结合同位素地质学资料，本认为武当地块基性岩席群所代表的这次拉伸作用与略洋的打开是同一构造背景下不同阶段的产物。

GEOCHEMISTRY OF THE SHEET-LIKE BASIC SWARM IN WUDANG BLOCK AND ITS TECTONICS SIGNIFICANCE

There are a lot of tabular basic intrusive bodies in Wudang block of South Qinling Orogenic zone. It has been confirmed, in tectonics, that they intruded into the Middle Proterozoic Wudangshan group during the Paleozoic extensional process of Wudang block. The geochemistry of the sheet-like basic swarm shows that they are similar to that of diabases of ophiolites in Mianlue suture zone. It is very possible that the opening of Mianlue ocean and the intrusion of the sheet-like basic swarm were the results of different extensional stages during the same extension in South Qinling zone.