摘要
我国东部地区数十条断裂带横剖面上断层岩的化学分析资料表明，硅含量的递变有明显的规律。从变质作用、成分组合、显微构造、分带分异和构造背景等的不同表现，元素硅的地球化学行为可分为低级变质作用和甚低级变质作用两种类型。硅在断裂带中变化的复杂性，依实例分析同Ｋ石的分解密切相关，此系动力分异的多期性所导致的变质分异和化学分界多次性的结果，并形成ＳｉＯ２－Ｋ２Ｏ－Ａｌ２Ｏ３－ＭｇＯ－ＭｎＯ等多种硅的动力变质平衡系统。文中最后还简述了上述讨论对资源环境地质研究的意义。
Based on the data of chemical analyses of the fractured rocks within cross sections of a few tens of fault zones in eastern China, there are obviously successive change pattern for the content of element Si, and from various different presents including the metamorphism, component composition, micro-structure, zonal differentiation, and tectonic background etc., the tectono-geochemical behaviour of the element Si can be divided into a low grade metamorphism type (abbreviated as L type) and a very low grade metamorphlsm type (VL type). In the former, the metamorphic temperature is more than 200°- 250 ℃, and the metamorphic factes matches with the greenschist. But in the latter, the metamorphic temperature is less than 200 ℃, which coincides the zeolite metamorphic factes.As a matter of fact the complex change of element Si in fault zones is closely correspond lug to feldspars in practical examples. Obviously multi-period features of the dynamic differentiation can result in the mult-times of metamorphic differentiation and chemical differentia non. Thus many kinds of dynamic metamorphic equilibrium systems of the element St could be formed such as SiO2 -K2O -Al2O3 -MgO -MnO and so on. Finally the significance of the discussion mentioned above to the geological research of resources and environment has been briefly described. On the one hand, most of mylonites hosting gold ores are some siliceous mylonites, and they were distributed in many provinces in the eastern area of China. On the other hand, the silicified rock can weld fault zone to prevent the sliding slope,and these phenomena are often discovered in the Lower Yangtzi area.
出处
《高校地质学报》
CAS
CSCD
1996年第1期38-47,共10页
Geological Journal of China Universities
基金
国家自然科学基金
关键词
断裂带
元素硅
化学活动类型
变质平衡系统
fault zone, element Si, chemical activity type, metamorphic quilibrium system
