Study Of Major Quaternary Faults In Jiaozuo Area

Jiaozuo area is located in the northwest of Henan Province. The tectonic position is onthe south end of Taihang Mountain piedmont fault zone, and Taihang uplift is in the north,Jiyuan-Kaifeng depression in the south, and Tangyin Graben and Neihuang salient in theeast. Of the nine Quaternary faults in the researching area, Jiulishan fault, Mafangquanfault and Baobi fault is NE direction, Fenghuangling fault, Pangu Temple-Xinxiang fault,Jiyuan-Bo’ai fault, Zhuying fault is near EW direction, and Wuzhi fault, Pingling fault isNW direction.In this paper, based on geological survey, remote sensing image data interpretation,drilling data analysis, data interpretation of shallow seismic reflection and other researchmethods, we establish the quaternary standard section of Jiaozuo Area, put forward thequaternary stratigraphic division and correlation proposal, and study the movementcharacteristic of three major faults (Baobi fault, Fenghuangling fault, PanguTemple-Xinxiang fault) of Jiaozuo area in Cenozoic, especially in Quaternary. Combinedresults of previous studies and detecting results of standard drilling of Jiaozuo city todetermine the Holocene Epoch (Qh) bottom boundary depth of about5to6m, upperPleistocene Epoch (Qp3) bottom boundary depth of about63to88m, and middlePleistocene Epoch (Qp2) bottom boundary depth of about175to200m in Jiaozuo area, thestratum of Holocene Epoch (Qh) is relatively flat, the stratum of middle Pleistocene Epoch(Qp2) and upper Pleistocene Epoch (Qp3) is undulating, the stratum of Qp2contact with thestratum of N2for parallel unconformity, the stratum of Qp1is missing. In the fieldgeological section investigation, Baobi faults, in the NW direction, are showed significantlinear structural features in the remote sensing image, and found fault outcrop section,without dislocation on the top cover of the late Pleistocene Epoch. Combined with Jiaozuostandard profile characteristics of Quaternary and the results of high-density electricalmethod, we find faults had strong activities in Paleogene and Neogene, dislocationactivities in succession in early and middle Pleistocene Epoch, and no clear activity sincethe late Pleistocene Epoch, the latest activities era is the early Middle Pleistocene Epoch,fault extends to the southwest near the Xufan village of Jiaozuo city. Fenghuangling faultin near EW direction and Pangu Temple-Xinxiang fault in the north and west of Jiaozuomountains are found to have fault outcrop section. In remote sensing image, there is a significant linear structural feature on the western and middle of Fenghuangling fault,while the eastern part concealed under the Quaternary unconsolidated sediments, beingunrecognized. Combined with the results of shallow seismic reflection to determine theFenghuangling fault having the segmental nature. The latest activities era is the late MiddlePleistocene Epoch in middle of the fault, it is from the late Early Pleistocene Epoch to theearly Middle Pleistocene Epoch in the east of the fault, and it is the late Mesozoic Epoch inthe west of the fault. Pangu Temple-Xinxiang fault also has the same segmentalcharacteristics, with western and middle small part showing a clear linear structural feature,and the majority of middle and eastern parts concealed under the Quaternaryunconsolidated sediments in the remote sensing image. Combined with the results ofshallow seismic reflection, we could determine the latest activities era is the late MiddlePleistocene Epoch in the middle of fault, it is the early Middle Pleistocene Epoch in theeast of the fault, and it is from the late Early Pleistocene to early Middle Pleistocene thewest of fault.Major faults in Jiaozuo region have undergone intense activities during the earlyPleistocene, moderate activities in the middle Pleistocene Epoch. There is not the tectonicactivity in Baobi fault since the late Middle Pleistocene Epoch; there is the tectonic activityin the middle of Pangu Temple-Xinxiang fault and Fenghuangling fault during the lateMiddle Pleistocene Epoch.