北京南口-孙河断裂带北段晚第四纪活动的层序地层学研究  

SEQUENCE STRATIGRAPHY STUDY OF LATE QUATERNARY ACTIVITIES OF NANKOU-SUNHE FAULT IN ITS NORTHERN SEGMENT,BEIJING

作　　者：张世民[1] 王丹丹[1] 刘旭东[1] 任俊杰[1] 罗明辉[1] 张国宏[1] 赵国存[1] 王瑞[1] 张英礼[1] 

机构地区：[1]中国地震局地壳应力研究所,北京100085

出　　处：《地震地质》2007年第4期729-743,共15页Seismology and Geology

基　　金：国家发展与改革委员会发改投资"城市活断层试验探测"项目(20041138)资助

摘　　要：文中采用钻探技术对南口-孙河断裂带进行了试验探测研究,并通过层序地层学、岩性岩相分析、磁化率分析与年代测定等方法建立了钻孔联合剖面,进而研究了断层距今60ka以来的多期活动特征,得出断裂带的3个活跃期是60～47kaBP、36～28kaBP与16kaBP以来,其余时段为相对平静期。断裂带的平均垂直位错速率,距今60～37ka之间约为0.35mm/a,37～32ka之间为0mm/a,32～12ka之间为0.78mm/a,12ka以来为0.35mm/a。研究认为,与传统的岩性、沉积相分析方法相比,层序地层学方法在钻孔地层对比与隐伏断层活动分期研究中有一定的优势。In water area, shallow groundwater area and plains with thick Quaternary sediments, drilling is necessary for active fault survey. Due to complex facies change of Quaternary terrestrial formation, there is no mature scheme for the key problems such as borehole arrangement,decision and correlation of isochron surfaces and deciphering of episodic activity of fault. A test of drillhole exploration was implemented across the northern segment of Nankou-Sunhe Fault buried under Beijing plain. Based on the data of shallow seismic investigation, we drilled a row of boreholes. A combined borehole section was built by sequence stratigraphy,lithology and facies analysis, magnetic susceptibility and absolute chronology, which can define the location ,geometry and accumulated displacements in several time spans. The result shows that the fault has an episodic movement since 60ka BP. The active stages of the fault are 60ka to 47 ka BP,36ka to 28ka BP, and 16ka to present, respectively. Other intervals are relatively stable. The average vertical slip rate is 0. 35mm/a from 60 ka to 37ka BP, 0mm/a from 37ka to 32ka BP,0.78mm/a from 32ka to 12ka BP,and 0.35mm/a since 12ka BP. Stratigraphic cyclicity is the main issue of sequence stratigraphy. The cyclicity is of multilevel character. Controlled by climate fluctuations, tectonic movements and matter source factors, each sequence has a specialty itself as effective index to the correlation of borehole strata. Correlation of borehole strata from big to small sequence in turn can effectively reduce the blindness and the uncertainty. Hiatus of sediment strata of low base level such as low-water-level system territory and transgression territory on uplifted side indicates existence of fault scarp and active stage of fault slip. Along with the rise and later fall of base level, together with the attenuation of fault activity, high-water-level system territory and regression system territory may deposit on the uplifted side. Contrarily,homo sequence on both sides indicates weak acti

关 键 词：南口-孙河断裂带 钻孔探测 隐伏活动断层 层序地层学 

分 类 号：P315.2[天文地球—地震学]