内蒙古亚干变质核杂岩与伸展拆离断层  

THE YAGAN METAMORPHIC CORE COMPLEX AND EXTENSIONAL DETACHMENT FAULT IN INNER MONGOLIA

作　　者：郑亚东[1] 张青[1] 

机构地区：[1]北京大学地质学系

出　　处：《地质学报》1993年第4期301-309,共9页Acta Geologica Sinica

基　　金：国家自然科学基金(49070135)

摘　　要：本文阐明了内蒙古亚干变质核杂岩的构造组成与特征,特别是拆离断层本身及下盘中的各种伸展构造,对变质核杂岩的年龄也进行了较详细的讨论。亚干变质核杂岩(侏罗纪)与科迪勒拉的变质核杂岩(第三纪)的特征基本相似。其基本构造要素:(1)下盘为糜棱状片麻岩;(2)绿泥石化角砾岩;(3)假熔岩和燧石状碎裂岩或微角砾岩;(4)未变质或轻微变质的上盘岩石和邻近拆离断层的一层断层泥或未粘结的断层角砾。但与科迪勒拉区不同的是,亚干变质核杂岩的下盘,有许多不同样式的伸展断层,从韧性低角正断层,经脆韧性断层到脆性高角正断层。The paper describes the features of the Yagan metamorphic core complex, especially the detachment and various extensional structures in the footwall. The age of the complex is discussed in some detail as well. The basic features of the Yagan metamorphic complex (Jurassic in age) are similar to those of the metamorphic core complex in the Cordilleran area (Tertiary in age); they are as follows: (a) mylonitic gneisses in the footwall, (b) chloritized breccias, (c) pseudotachylites and flinty cataclasites or microbreccias, (d) unmetamorphosed or epimetamorphic rocks in the hanging wall with a layer of fault gouges or incohesive fault breccia adjacent to the detachment fault, In contrast to its Cordilleran counterparts, however, there are lots of extensional faults with different styles (from ductile low-angle normal faults through brittleductile faults to brittle high-angle normal faults) in the footwall.

关 键 词：糜棱岩 超碎裂岩 断层 变质核杂岩 

分 类 号：P588.33[天文地球—岩石学]