青藏高原东北缘断层泥的研究

STUDIES ON FAULT CLAY ALONG NORTHEASTERN MARGIN OF QINGHAI-XIZANG PLATEAU

摘要:

本文对青藏高原东北缘一些主要断裂(包括阿尔金、昌马、毛毛山等断裂)的断层泥首次进行了研究。在对断裂带的内部结构、围岩成分、断层泥的厚度及石英颗粒表面特征等综合分析的基础上对断裂的活动年代、活动方式及断层泥形成的深度进行了讨论。石英颗粒表面上溶蚀程度(颗粒表面的光滑程度、凹凸现象及孔洞发育情况)可划分为6种类型并且每种类型都有相应的年代。根据断裂的粘滑、蠕滑特征,对该区的各活动断裂进行了粘滑段与蠕滑段的划分。用红外光谱与稀土元素的分析结果,算得断层泥形成的深度在地壳10km范围内。

Abstract:

The fault clay of some principal faults,including Altun,Changrna and Maornaoshan faults,along the northeastern border of Qinghai-Xizang Plateau is first studied. On the basis of the comprehensive analyses of the inner structures, country rock composition,fault clay thickness and quartz grain surface features within a fault zone,the fault activity ages and ways as well as the depth of fault gouges are discussed. The surface corrosion degrees of quartz grains can be classified into six types and each type has a corresponding age. The division standards of fault activity natures are proposed,by which the stick-slip and creep slip parts of a fault zone can be divided. Through the infrared spectroscopic analysis and rare earth element analysis, it is considered that the fault gouge formed at about 10 km depth within the crust.