摘要
中国东部燕山期火成岩构造组合可识别出两种类型,大多数的火成岩具有类似于安第斯和美国西部的大陆边缘弧的岩石学与地球化学性质;南岭地区则发育海西型黑云母、二云母和白云母花岗岩组合。沿岩浆构造带可识别出3个火成岩段。按岩浆—构造事件序列,北、中、南段分别为反时针、顺时针和反时针+顺时针的pTt轨迹。在中段,玄武岩岩浆底侵作用发生于陆壳增厚之后,即顺时针pTt轨迹的造山—深部过程被认为是钾玄岩组合占优势发育的主要原因。本文提出,类似安第斯的造山带是由于大陆岩石圈的拆沉(丢失了约120km的大陆岩石圈根)与大洋俯冲作用的联合所致,而海西型的南岭造山带则是陆内俯冲作用与陆壳—岩石圈的巨大增厚作用所致。因此,中国东部燕山期是复合型(大陆边缘造山与大陆碰撞造山)造山带。
Two types of Yanshanian igneous petrotectonic assemblages in East China are recognized: most of the igneous rocks is characterized by the continental marginal arc in petrology and ge-chemistry like Andes and west USA; and the Hercyn-type biotite-, two mica-, and muscovite granite belt is developed in the Nanling region . Three segments of Yanshanian igneous rocks a-long the belt have been recognized. In terms of the magma-tectonic event sequence, the north, middle and south segments have CCW, CW,and CCW + CW pTt path, respectively. The CW pTt path of the middle segment, indicated from the basaltic magma underplating after the crustal thickening, is believed to be a cause for the dominant developing of the shoshonitic rock assemblage. This paper suggests that, the Andes-like orogenic belt resulted from the lithosphere de- lamination (loss of about 120 km continental lithosphere root) in combination with the oceanic subduction, and the Hercyn-type Nanling orogenic belt is formed due to both the lithosphere and the crust thickening. Thus, the orogenic belt of Ease China in Yanshanian is believed to be a composite orogenic belt of continental marginal and continental collision orogeny.
出处
《地质论评》
CAS
CSCD
北大核心
2000年第1期41-48,共8页
Geological Review
基金
国家攀登专项 (编号SSER-111-2)
国土资源部项目 (编号9501112
9501102-04-02
9501105-03-02)
国家自然科学基金 (编号49772155)
关键词
中国
燕山期
火成岩
构造组合
造山--深部过程
Yanshannian igneous petrotetonic assemblge
orogenic-deep processes
CCW/ CW pTt path
