栟茶河断裂第四纪活动性最新研究

The newest research on the Benchahe fault in Quaternary activity

栟茶河断裂是20世纪50年代石油部门在开展石油勘探时发现的。由于该断裂的隐伏性,很多地学家对该断裂的活动性提出了质疑。本着求实的科学精神,我们通过多层次、多波浅层地震勘探、钻孔联合剖面探测以及新地质年代测定等技术方法,对栟茶河断裂的活动性展开调查。关于栟茶河断裂得出以下结论:(1)在浅地震有效探测深度范围内,栟茶河断裂并非单一的一条断层,而是由2条N倾断层组成的断阶带,且断裂带宽度自SE往NW具收敛趋势;(2)证实了栟茶河断裂是走向NWW、视倾角约为60°~75°、上陡下缓的铲形正断层;(3)南支(F_(1-1))是主要、新活动明显的断面;(4)由南支(F_(1-1))断错中更新统顶部的黏土层,推测其最新活动时代为中更新世晚期至晚更新世早期。

The Benchahe fa u lt,f irst proposed by petroleum system in the fifties of last century,has always received attention and research because of its importance and complexi-ty . Many geoscientists have questioned the activity of the target fault. Based on the scientiticspirit of matter-o-- fact,we carried out an investigation on its activity by means of shallow seismic exploration of multi-level and mult- wave, borehole composite profile analysis and geological dating. From this study,we can draw several conclusions① within the detection depth, t s not a single fault but a fault-terrace belts consisting of 2 N-dippingfaults. The width of fault zone has a trend of convergence from SE to NW.② The Benchahe fault is running in NWW and its apparent dip angle is about ,its common structural forms are the shovel-like normal fault and spoon-like normal fault. ③ The souther（F 1-1） is the main section and has obvious new activity.④ The southern branch （F 1-1） dislo-cated the clay layer at the top of Miiddle Pleistocene. We suspect that the newest active time of the south branch s late mid-Pleistocene to early Late Pleistocene.