江苏镇江地区主要活动断裂及其晚第四纪活动性研究

RESEARCH ON THE MAJOR ACTIVE FAULTS IN ZHENJIANG,JIANGSU AND THEIR LATE QUATERNARY ACTIVITIES

镇江地区位于宁镇山脉东端,地质构造复杂,尤其断裂构造的活动性塑造了镇江地区如今的地形地貌格架。通过地质地貌调查、遥感影像解译、地球物理勘探、钻探、探槽等勘探手段,对镇江地区断裂构造两侧第四纪地层进行年代学研究,基本确定了断裂构造的活动机制、活动时间,结合镇江地区地震发生的规律及地应力场特征的研究,认为镇江地区断裂构造的最后活动时间在更新世,全新世活动较弱,并趋于稳定。

Combined with a series of measures from geophysical exploration,drilling and trench,through surveying the geomorphology and interpreting the remote sensing image at Zhenjiang,Jiangsu province,we discussed the age of Quaternary strata at both sides of Zhenjiang fault,then confirmed the activity mechanism and activity time of the fault. Research showed that the faults formed in different periods divided by directions include NE-NEE,NW,nearly EW,nearly NS and strike thrust（ eversed） faults associated with fold,etc. Strike thrust（ eversed） faults and early nearly EW trending faults formed in the late Indosinian to early Yanshanian fold orogenesis,NENNE trending and NW trending faults are the largest faults,formed mainly in Yanshan regional fault blockperiod. Nearly SN and late nearly EW trending tectonics controlled the spacial distribution of the Cenozoic sedimentary depression,which formed in late Yanshanianto Himalayan period. The faults that have inheritance activities include Mufushan-jiaoshan fault,Maoshan fault（ belt） and fault along the river since the Quaternary,they are the main fault tectonics to Shape the modern landscape. Combining the regularity of seismic occurrence at Zhenjiang region with the charactristics of stress field,we consider the last activity time of the fault tectonics in Zhenjiang region is Pleistocene,activity is weak at Holocene,and then tends to be stable.