湖北铁山与北京西山复合石香肠的初步研究

PRIMARY STUDY ON COMPOSITE BOUDINS IN TIESHAN, HUBEI AND XISHAN, BEIJING

湖北铁山地区发育接触热动力变质带 ,叠加了热动力和构造变形作用 ,这使该区岩体附近互层的灰岩和泥岩变质为大理岩和角岩 ;而且这两者之间存在有较大的粘度差。这就为石香肠构造的发育提供了充要条件 ,所以在湖北铁山地区形成了形式多样的石香肠。北京西山地区震旦系互层的灰岩和白云岩也存在明显的粘度差异 ,在构造变形作用下 ,也广泛发育有石香肠构造。结合湖北铁山和北京西山地区的复合石香肠 ,依据石香肠横断面形态把复合石香肠分为 , , 三类 ,并分析了每种类型的成因。复合石香肠是一种有特殊意义的石香肠构造 ,其特点是具有复合的形态特征 ,复合的构造成因。研究复合石香肠对了解其发育过程有重要的研究价值 ,对区域构造运动方向和期次的判定也有重要的指示意义。

There is a contact thermodynamical metamorphic zone developed in Tieshan of Hubei, The Tieshan region underwent complex magmatic emplacement and structural deformation. Nearby the Tieshan pluton, there is a great viscosity contrast between hornfels and marble, which are the products of contact metamorphism. Just under these conditions, different boudins developed in the layers consisting of the competent bed (hornfels) and matrix (marble). In Xishan of Beijing, the boudins developed when the strata of lime dolomitite and dolomitic limestone underwent multiperiodic tectonic movement. In these two regions, the authors find some new types of boudins. They can be called composite boudinage, and divided into three classes that totally include seven types based on the cross section. In this paper, the authors not only pay attention to the description, classification, but also to the cause of formation of composite boudinage and its significance. Composite boudinage contains some important geological significance, but receives few investigations at home and abroad. The analysis to the causation of formation of composite boudins can be helpful to understand its development. Meanwhile, composite boudins can be used to determine the direction and differentiate sequence of the tectonic movement and rheological evolution of rocks.