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为探索断裂晚第四纪以来新活动的微观依据,我们以郯庐断裂带宿迁北马窑开挖探槽断层新活动断错物质为主要研究对象,结合前人工作对比分析,识别编录晚第四纪以来变形和史前地震事件遗迹,分析其活动习性,定向采集断错物质,进行显微构造分析.发现一系列丰富复杂的微观变形组构和组合.镜下多处可见张压显微变形共处、变形带被切割等二次变形现象,显示该段至少有过2次活动,早期表现为拉张,晚期显示为挤压.宏、微观构造分析结合年代分析表明,晚第四纪以来,该断层段先行引张,然后发生强烈的挤压逆冲活动,均可能伴随强烈的史前地震活动,最新活动处晚更新世末期,年代分别为距今约为1.5万年和1.2万年.
In order to explore the microscopic basis of the new activities since the late Quaternary Faults, we take the fault activity of the new activities in the exploration trench of North Maja in Suqian fault belt as the main research object. Combining the predecessors’ work, Deformations and remnants of prehistoric earthquake events since the Quaternary period, analysis of their activity habits, directional acquisition of fault-finding material, and microscopic structural analysis revealed a series of complex and complex microstructures and combinations of micro-deformations. Coexisting and deformed zones were cut, showing that there were at least two activities in this section, with early extensional expansions and late compressional compaction.Macro-microstructural analysis and dating analysis show that since the late Quaternary, The extension of the fault zone first followed by intense extrusion and thrusting activities may be accompanied by strong prehistoric seismic activity. The late Pleistocene epoch was located at about 15,000 years and 12,000 years ago, respectively.