| Recent years, the world entered into a strong earthquake active period once again. We canestimate the activity time of the active fault according to the quaternary strata was transformationor not and the position was diastrophism or not. So, study the quaternary stratigraphic frameworkand basin evolution played an important role in the research of earthquake and seismic structure.Nantong is located in the Yangtze continental block and in the east section of Yangtzemassif, Quaternary in the area mainly belongs to lacustrine facies strata, the stratum wascompletely developed and the sequence was clear. This paper discussed the exact position andthe characteristics of tectonic activity of the Natural harbor-Wolf mountain fracture (F1) bydividing and correlating of the Quaternary strata and analyzing of the stratigraphic framework inthe research area.According to analyzing the lithology、sedimentary cycleand sedimentary facies of12dirlling hole in junshan site、jiangshan road site and xingyu road site, and synthesizing thepredecessors’ research results and the controlling drilling plan, this paper Divided it’s quaternaryrock srtaitgraphy as Rudong Fm. of Holcoene Epoch(QhR) Gehu Fm.(Qp3G) and KunshanFm.(Qp3K) of upper Pleistocene Epoch Qidong Fm. Of middle Pleistocene (Qp2Q) and HaimenFm. Of lower Pleistocene (Qp1H).Judging by the Dating data of the drilling across the fault, and synthesizing the achievementof pollen assemblages and grading analysis in the Controlling drilling, this paper discussed theclassification standard of chronostratigraphic in this area, made a detailed summary and analysisof Quaternary division in Target zone of nantong. Finally draw the conclusion that the averagebottom boundary of Qh was40.4m Qp3was107.8m Qp2was147.0m and Qp1was209.6m.Through analyzing the lithostratigraphy of Quaternary Period of junshan site and jiangshanroad site whith control the Natural harbor-Wolf mountain fracture (F1), comprehensived theachievement of shallow artificial seismic exploration and combined petroleum geology、tectonicgeology and seismogeology, this paper discussed Natural harbor-Wolf mountain fractures’breakpoint location and the characteristics of tectonic activity from Quaternary period.Identifiedseveral dislocation interfaces of lower Pleistocene in Junshan site(breakpoint F1-1) and injiangshan road site(breakpoint F1-2), and the offsets present a Successively increasing trend from the top to down. Conclusions are reached through synthetic analysis, the of the Naturalharbor-Wolf mountain fracture (F1) was a normal faults and striked with NNW diped withSWW, and the newest active time was about early Pleistocene. |
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