江苏如东洋口地区断裂特征及其意义

CHARACTERISTICS OF THE FRACTURES IN YANGKOU AREA,RUDONG,JIANGSU PROVINCE AND ITS IMPLICATION

结合已有地热钻孔采用多种物探方法研究了江苏如东洋口地区断裂的空间展布特征。研究结果表明,洋口地区分布3组断裂,分别为隶属滨海断裂的北西向雁行型次级断裂、近东西向栟茶河断裂及海安—河口断裂。北西向雁行型次级断裂为4条,主要分布于洋口地区北段及老坝港地区,断裂陡倾,倾向北东,倾角70°—80°,推测切穿至新近系。栟茶河断裂由3条次级断裂组成,主要分布于洋口地区中段,断裂走向近东西,倾向北,整体呈曲折状延伸,倾角60°—80°。结合以往地震地质特征以及地热钻孔资料,认为栟茶河断裂为活动性断裂,切穿了第四纪全新世地层,全新世地层断距较小。断裂的活动性影响如东洋口经济开发区的建设与发展。海安—河口断裂自海安延伸至洋口地区南段,走向近东西,倾向南,倾角约为70°,切穿古近纪地层。洋口地区断裂的分布与该地区地热资源分布具有良好的对应关系,其对于该地区地热资源开发具有良好的指导意义。

Fracture characteristics in Rudong Yangkou area,Jiangsu province have been studied through various geophysical methods combined with geothermal drilling data in this paper. Results indicate that there are three fault systems in Yangkou area,including a NW-trending secondary fault system of Binhai fault,EW-trending Benchahe fault system and Haian-Hekou fault. The NWtrending secondary fault system contains four secondary faults,mainly distributed in the north of Yangkou area and Laobagang area. The faults are steeply NE-dipping,with dip angles range from70° to 80°,and speculatively cut through the Neogene strata. The EW-trending Benchahe fault system contains three secondary faults,mainly distributed in the middle of Yangkou area. The faults are mainly north dipping, with dip angles range from 60° to 80°. Combined with previous seismogeological and geothermal data in Yangkou area, it is comprehensively speculated that Benchahe fault is active,which makes the Quaternary Holocene strata being cut off with minor displacement. The activity of Benchahe fault influences the safety in the construction and development of Yangkou Economic area. The EW-trending Haian-Hekou fault is south dipping with the dip angle about 70°,extending from haian to the south of Yangkou area and cut off the Paleogene strata. There is compatible corresponding relation between distribution characteristics of faults and geothermal resources in Yangkou area,which is of certain guiding significance for the geothermal resources exploitation in this region.