Jiangsu Earthquake Agency
Institute of Geology, China Earthquake Administration
CCTEG Xi’an Research Institute (Group) Co., Ltd.

山左口−泗洪断裂经历了郯庐断裂带整个演化阶段，该断裂的最新活动时代具有分段性。确定该断裂的活动性分段位置及原因对研究郯庐断裂带内各分支断裂的活动性变化具有重要的参考价值。因此，利用野外地质调查、浅层地震勘探以及钻孔联合地质剖面等深浅部相结合的立体式研究方法，对山左口−泗洪断裂的活动性进行了研究。结果表明：山左口−泗洪断裂在北马陵山东侧为晚更新世活动断裂，在新沂市为中更新世断裂。新沂市嶂仓村小学新发现一条晚更新世−全新世早期活动断裂，该断裂可将山左口−泗洪断裂分为南北两段，北段为晚更新世活动断裂，南段为早中更新世断裂，北段晚更新世以来活动量向南调整至嶂仓村小学断裂带。北马陵山为郯庐断裂带内部沿断裂走向展布的基岩山体，其第四纪以来的持续抬升与山左口−泗洪断裂的活动性变化有一定的耦合关系。该研究对认识郯庐断裂带其他分支断裂的活动性变化和丘陵山脉的形成机制具有重要的参考价值。

The Shanzuokou-Sihong fault, having undergone the entire evolutionary process of the Tancheng-Lujiang fault zone, exhibits segmentation during the latest activity epoch. Determining the location and origin of its activity segmentation will provide a significant reference for exploring the activity variations of its branch faults and their origins. This study investigated the activity of the Shanzuokou-Sihong fault using a three-dimensional approach combining field geological surveys, shallow seismic exploration, and cross-well stratigraphic correlation. The results show that the Shanzuokou-Sihong fault is a Late Pleistocene active fault on the east side of the North Maling Mountain and a Middle Pleistocene fault in Xinyi City. Moreover, a Late Pleistocene-Early Holocene active fault has been discovered recently at the Zhangcang Primary School in Xinyi City (also known as the Zhangcang Primary School fault). With the intersection of this newly discovered fault and the Shanzuokou-Sihong fault (northeast of Zhangcang Village) as demarcation, the Shanzuokou-Sihong fault can be divided into northern and southern segments, which are a Late Pleistocene active fault and an Early-Middle Pleistocene fault, respectively. Since the Late Pleistocene, the northern segment has extended southward to the Zhangcang Primary School fault due to fault activity. The North Maling Mountain is a bedrock massif within the Tan-Lu fault zone, distributed along the strike of the fault zone. Its continuous uplift since the Quaternary has a certain coupling relationship with the activity variations of the Shanzuokou-Sihong fault. This study will provide a valuable reference for understanding both the activity variations of other branch faults and the formation mechanism of hills and mountains in the Tancheng-Lujiang fault zone.

江苏省地震局青年科学基金项目(201802，202203)；中国地震局地震星火科技项目(XH18016Y)

张浩，李伟，李丽梅，等. 郯庐断裂带江苏段山左口−泗洪断裂活动特征变化及成因分析[J]. 煤田地质与勘探，2023，51(12)：29−37.

ZHANG Hao，LI Wei，LI Limei，et al. Activity variations of the Shanzuokou-Sihong fault within the Jiangsu segment of the Tancheng-Lujiang fault zone and their origins[J]. Coal Geology & Exploration，2023，51(12)：29−37.