北京平原南口—孙河断裂南段第四纪活动性及其构造意义

通过对北京平原南口—孙河断裂南段上、下两盘钻孔ZK17和ZK18的磁化率和自然伽马测井曲线进行频谱分析，识别出显著的米兰柯维奇沉积旋回，揭示出北京平原区第四纪古气候及沉积过程受到地球轨道力的控制。通过对初始年代格架下的数据曲线进行100 ka的短偏心率信号滤波处理并调谐至天文理论偏心率曲线，建立了精度为01 Ma的连续天文年代标尺，在此年代学研究成果的基础上实现了对目标断裂活动性精细探讨的目的。通过对比断裂两盘的沉积速率变化，可以识别出南口—孙河断裂第四纪以来6个相对较强的活动幕。其中早更新世存在4个明显的活动幕，活动周期具有04 Ma准周期的特点，第Ⅰ幕和第Ⅲ幕分别对应了青藏高原隆升期的青藏运动的B幕(26 Ma)和C幕(17 Ma)，中更新世的活动特征则对应了“昆黄运动”，北京地区新构造运动特征与之有较好的呼应关系。

Study on the Cyclic Stratigraphy Activity of Nankou-Sunhe Fault in Beijing Plain Since Quaternary and Its Tectonic Significance

As one of buried faults, Nankou Sunhe Fault is the only one northwest striking active fault in Beijing plain. In order to study its activity, this study analyzed characteristics of magnetic susceptibility and natural gamma ray for drillholes of ZK17 and ZK18, and the spectrum analysis was conducted on the magnetic susceptibility and natural gamma ray data of the two drillholes.ZK17 is located at the hanging wall and ZK18 is at the lower wall. Significant Milankovitch sedimentary cycles were respectively identified in the two drillholes, revealing that the Quaternary paleoclimate and deposition process in Beijing plain were controlled by orbital forcing. A continuous astronomical time scale was established by tuning the bandpass filtered 100ka short eccentricity signal from initial age constrained time series to the astronomical solutions, thus it got a fine way to study the faults activity. Six phases which are relatively active have been identified by the comparative study on deposition rate of the two walls, and four of them are in Early Pleistocene and the active period is 04 Ma. The first and third phases are correspond to the B (26 Ma) and C(17 Ma) periods of Qingzang Movement; the activity characteristics in the Middle Pleistocene are related to Kunhuang Movement; so the characteristics of neotectonic movement in Beijing plain have a good relationship to Qingzang and Kunhuang movements.