摘要
溧阳−南渡断裂是中国东部长三角地区一条重要的近EW向隐伏断裂,位于中国人口、经济和城镇密度最高区域之一苏南现代化建设示范区中部,是一条重要的区域地貌和新构造分区界线。溧阳−南渡断裂尚未见系统研究,其最新活动时代尚不明确。为此,采用纵横波联合地震勘探和钻孔联合地质剖面探测等方法研究溧阳−南渡断裂空间展布及第四纪活动性,并对其构造多期活动及地震活动性进行探讨。结果表明:断裂西段倾向向北;中东段倾向向南,具正断性质,倾角为64°~84°;断裂向上明显切错地表以下约70 m层位,垂直差异活动影响至地表以下36~45 m,综合分析认为应属第四纪早−中更新世断裂,最新活动时间在距今(310±54)ka之后、晚更新世之前。断裂具多期活动:印支期到燕山早期为逆断裂,燕山晚期以来为正断裂控制新生代盆地和火山岩发育。研究成果为苏南乃至长三角地区防震减灾、重大工程建设、城市规划及土地利用等提供科学依据。
Located in the central part of the Sunan Modernization Construction Demonstration Area−one of the areas with the densest population and urban areas and the most developed economy in China,the Liyang-Nandu fault is an important concealed fault with a nearly E-W strike in the Yangtze River Delta in eastern China.This fault serves as an important regional geomorphic and neotectonic boundary.However,there is a lack of systematic research on this fault,and its latest activity era is yet to be ascertained.Using seismic exploration P-waves and S-waves and cross-well stratigraphic correlation,this study investigated the spatial distribution and Quaternary activity of the Liyang-Nandu fault and explored its multiphase tectonic activity and seismicity.The results are as follows:(1)The western and central-eastern segments of the Liyang-Nandu fault have dip directions of north and south,respectively,suggesting the nature of a normal fault.Their dip angles range from 64°to 84°.(2)This fault evidently offsets the intervals above at burial depths of approximately 70 m,with vertical activity difference affecting the parts at depths of about 36-45 m underground.The comprehensive analysis revealed that this fault should be a Quaternary Early-Middle Pleistocene fault,with the latest activity occurring after approximately 310±54 ka,predating the Late Pleistocene.(3)This fault has undergone multi-stage activity.From the Indosinian to the Early Yanshanian,it was present as a reverse fault.Since the Late Yanshanian,it has been a normal fault,controlling the development of Cenozoic basins and volcanic rocks.These results will provide a scientific basis for the prevention and reduction of earthquake-induced hazards,major engineering construction,urban plan-ning,and land use in southern Jiangsu and even the broader Yangtze River Delta.
作者
张硕
张平
陈火根
许书刚
龚绪龙
许汉刚
李丽梅
冯文立
何宗南
ZHANG Shuo;ZHANG Ping;CHEN Huogen;XU Shugang;GONG Xulong;XU Hangang;LI Limei;FENG Wenli;HE Zongnan(Geological Survey of Jiangsu Province,Nanjing 210018,China;Key Laboratory of Earth Fissures Geological Disaster,Ministry of Land and Resources,Nanjing 210049,China;Jiangsu Earthquake Agency,Nanjing 210014,China;Geophysical Exploration Center,China Earthquake Administration,Zhengzhou 450002,China)
出处
《煤田地质与勘探》
EI
CAS
CSCD
北大核心
2023年第12期47-56,共10页
Coal Geology & Exploration
基金
苏南现代化建设示范区综合地质调查项目。
关键词
溧阳−南渡断裂
第四纪活动性
隐伏断裂
活动性
浅层地震勘探
钻孔联合地质剖面
Liyang-Nandu fault
Quaternary activity
concealed fault
activity
shallow seismic exploration
cross-well stratigraphic correlation
