摘要
夏垫断裂为河北平原北部的重要活动断裂,受断裂影响西侧大兴凸起与东侧大厂凹陷第四系沉积厚度差异较大.通过对比夏垫断裂北段上下两盘钻孔沉积物组合和沉积速率,对夏垫断裂北段第四纪以来的活动性进行了初步的研究.通过计算可知大兴凸起上D1钻孔早更新世沉积速率为36.4 m/Ma、中更新世沉积速率为186.6 m/Ma、晚更新世沉积速率为185.4 m/Ma;大厂凹陷内S9钻孔早更新世沉积速率为25.8 m/Ma、中更新世沉积速率为87.7 m/Ma、晚更新世沉积速率为264.6 m/Ma.通过对比断裂两侧凹陷内和凸起上不同时期地层沉积厚度和沉积速率,推测夏垫断裂北段在上新世就一直活动,早更新世和中更新世断裂活动增强,晚更新世断裂活动开始逐渐减弱.
Abstract
The Xiadian fault is the major faults in the North of Hebei Plain.The thickness of quaternary strata between the west side Daxing uplift and the east side Dachang sag is different greatly because of the influence of the Xiadian fault.According to the comparison of sediment assemblages and deposition rates of the boreholes which are hanging on the upper and lower plates of the north segment of the Xiadian fault,this paper makes a preliminary study on its activity since the Quaternary period.We obtained the deposition rates of the borehole D1 in Early Pleistocene,Middle Pleistocene and Late Pleistocene,being 36.4 m/Ma,186.6 m/Ma and 185.4 m/Ma respectively.The deposition rates of the borehole S9 in Early Pleistocene,Middle Pleistocene and Late Pleistocene,being 25.8 m/Ma,87.7 m/Ma and 264.6 m/Ma,respectively.By comparative analysis of the sedimentary thickness and deposition rate of the Quaternary strata between both sides of the fault,it is speculated that the north segment of the Xiadian fault has been active since the Pliocene,the fault activity increased in the early and middle Pleistocene,and gradually weakened in the Late Pleistocene.
维普
万方数据