中国庐山第四纪沉积砾石的显微构造系统及地质环境动力学分析

经过多年的区域地质调查和第四纪环境演变的分析, 对庐山芦林盆地大校场谷口剖面松散沉积物中变形砾石进行岩石显微构造学的研究。发现变形砾石内部存在特殊的微裂隙组构, 呈现出错裂-横裂-劈裂-爆裂-复裂-应力矿物等的复杂组合, 其结构面特征反映出显微构造形迹的力学性质是互为转变的。通过物理模型分析和试验变形比对等综合材料证明, 变形砾石是遭受了既密集、又分散、还具有同时发生作用的长时期的多边界外力条件及平衡力系, 内部形成破裂其应力传递过程和性质改变与变形形迹转变及其做功连续扩展, 是由低于疲劳极限的具有脉动性作用微弱应力造成的。地球陆表过程和地质环境要素及其动力学机制的研究认为, 只有第四纪晚期地质事件的低温、低应力及其分散密集的多颗粒平衡力系的缓慢长期及间歇脉动作用的边界条件才能满足、符合及形成这种特殊的岩石变形构造, 为中国东部山地可能遭受第四纪冰冻环境及冰川作用提供了新的科学证据。

A Dynamic Analysis of the Geological Environment and Micro-structural System of the Quaternary Sedimentary Gravelsin the Lushan Area of China

Based on many years work of regional geological investigation and an analysis of Quaternary environ-ment development, the authors studied the microscopic structure of the deformed gravels in loose sediments along the Dajiaochang valley section in Lulin basin of Lushan area and detected the existence of the special mi-cro-fissure fabric inside the deformed gravel, which assumes the complex assemblage of displacement crack -transversal crack - cleavage crack - explosion crack - composite crack - stress minerals, whose structural plane characteristic show that the mechanic qualities of the microscopic structure features are interchangeable. Synthetic material data and physical model analysis as well as experimental deformation contrast have demonstrated that the deformed gravel underwent the prolonged and simultaneous multi-boundary external force condition and the equi-librant system characterized by intensiveness and scattering. The internal breaking, the stress transmission process, the quality variation with the change of the transformation structure features and the continuous expansion of the work-doing resulted from the weak stress of the pulsation action lower than the fatigue limit. Researches on the earth's land surface processes and the geological environment essential factor and its dynamic mechanism have demonstrated that only with the equilibrant system of the low-temperature and low-stress and the scattered as well as dense multi-grains, the boundary condition for the slow, long-term and intermittent pulsation action can meet the formation conditions of such a rock deformation structure. These achievements have provided new scientific evidence for the possible existence of Quaternary frost environment and glacial action in mountainous areas of eastern China.