郯庐断裂带中-南段中生代岩浆活动的构造背景与深部过程  

TECTONIC SETTING AND DEEP PROCESSES OF MESOZOIC MAGMATISM IN MIDDLE-SOUTH SEGMENT OF THE TAN-LU FAULT

作　　者：牛漫兰[1] 朱光[1] 刘国生[1] 王道轩[1] 宋传中[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009

出　　处：《地质科学》2002年第4期393-404,共12页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目 (编号 :49872 0 74)资助

摘　　要：郯庐断裂带内岩浆岩及糜棱岩的年龄及野外研究表明以中 酸性为主的岩浆活动主要发生在早白垩世走滑运动的晚期 ,岩石化学以富钾、富碱为特征 ;稀土元素以轻稀土富集、重稀土亏损为特征 ;微量元素表现出富集大离子亲石元素 ,尤其是强不相容元素 ;同位素组成显示岩浆来源于壳幔过渡带。带内岩浆活动明显受断裂带控制 ,走滑晚期的岩浆活动起源于地幔底侵、壳幔相互作用下的壳幔过渡带 ,在伊泽奈崎板块斜向俯冲、中国东部遭受区域性剪切—挤压的背景下出现。在此背景下中国东部发生了岩石圈减薄 ,同时出现了一系列北东—北北东向已深切至壳幔边界的左行平移断裂系 。The isotopic ages of Mesozoic igneous rocks and mylonites and field survey revealed that the Mesozoic magmatic activities along the Tan Lu fault mainly occurred in the later stage of Early Cretaceous strike slip movement and formed a set of igneous rocks characterized by intermediate acidic rocks. The rocks were rich in alkali, potassium, and notably rich in highly incompatible lithophile elements (Rb, Th, Ba and LREE). The magmatic activities in Shandong Anhui area should be controlled by the Tan Lu fault. The recent contributions, including isotope data, showed that the magmatic activities during the later strike slip stage originated from the transitional zone between the crust and mantle through the underplating and mutual crust mantle action; and the Tan\|Lu fault must have cut down into the crust mantle boundary. Under a tectonic setting of oblique subduction of the Izanagi Plate, the East China continent suffered from a regional stress field of transcompression. Therefore, the East China continent once experienced lithospheric thinning and a group of NE or NNE striking sinistral shearing created, which resulted in a large scale magmatic activities.

关 键 词：中生代 郯庐断裂带 岩浆活动 构造背景 岩石化学 断裂活动 

分 类 号：P588.1[天文地球—岩石学]