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近几年来,“活动断层”研究已引起地震地质学者和工程地质学者的重视。在有潜在不稳定地区建设大水库、大工程或电站时,这一问题更显得重要。从地震设计的观点,应该研究断层和破碎带的范围和活动性,评价它们的稳定性。最重要的是测定它们最近的活动期。这些方法的使用,通常有一定的局限性,只能用于含有适合年龄测定的某些矿物样品。如果这些方法不适用,就必须寻找其他途径。随着研究的深入,新的方法不断地出现,如:电子自旋共振法和断层粘土矿物的钾氩绝对年龄测定法等,都是以断层产物为直接测定对象的。本文将介绍另一种新的判断活断层活动的相对年代方法。该方法是日本学者金折裕司等(1980)提出的。由于该方法是以断层产状中的石英碎砾为测定对象,利用其显微风化形貌结构来估计断层的活动期,制样和测定都较简易可行,易于推广。基本原理对沉积、冰川和风成成因的石英颗粒的显微形貌,已做过许多扫描电镜
In recent years, “active fault” research has attracted the attention of seismologists and engineering geologists. This problem is even more important when building large reservoirs, major projects or power stations in potentially unstable areas. From the point of view of seismic design, the scope and activity of faults and fractures should be studied to evaluate their stability. The most important thing is to measure their recent activity period. The use of these methods usually has some limitations and can only be used with certain mineral samples containing suitable age determinations. If these methods do not work, we must find other ways. With the deepening of research, new methods are emerging constantly, such as the electron spin resonance method and the absolute age determination method of potassium and argon of the fault clay minerals, which are all based on the fault products. This article will introduce another new relative dating method to determine active fault activity. The method is proposed by Japanese scholar Kim Hung-yu et al. (1980). Because this method is based on the quartz gravel in the fault shape, the micro-weathering structure of the fault is used to estimate the active period of the fault. The sample preparation and determination are simple and easy to be implemented. Fundamentals The microscopic morphology of quartz grains of sedimentary, glacial and aeolian origin has been studied by many scanning electron microscopy