Abstract: Theoretical consideration and method on evaluatng paleostress value of the fault zone are described by using the microstructure in mineral.The tectonic stress of the Yishui-Tongtou and Tongwu-Gegou ruptures on the norther part of the western branch of Yishui-fault zone in the late Yanshanian (post K₁) was calculated according to free dislocation density in deformed quartz crystal and percentage of deformed twin in calcite.The result shows that the stresses for the two crystals range from 1000-1500 b and 700-1100b,respectively.The microstructures of the fault zone show that the stable dislocation creep may occur both in the process of dry ductile/brittle-ductile deformation.Considering the effective water in the fault zone,it is likely that the evaluation can yield a real value by using McGomick relation rather than Weather's.

摘要： 本文侧重于利用变形矿物显微构造估算断裂带古应力值的一些理论分析和方法介绍。并以变形石英晶内自由位错密度ρ和方解石变形双晶百分比分别估算了沂沭断裂带西支北段的沂水-汤头断裂及鄌郚-葛沟断裂燕山晚期(K₁后)构造活动的应力值,其结果分别为1000-1500巴和700-1100巴量级。断裂带显微构造可能表明在地质时期的构造应力场作用中,稳态位错蠕变既可发生于韧性变形,又可发生于脆-韧性变形过程中。考虑到断层带“水”的因素,估算中采用McCormick关系式较Weathers关系式可能更接近实际。