基于反射地震资料探讨泥河湾盆地的新生代和中生代地层  

Study on the Cenozoic and Mesozoic Strata in the Nihewan Basin Based on Seismic Data

作　　者：朱小三[1] 钱荣毅[2] 王永[1] 董进[1] 迟振卿[1] 姚培毅[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质大学,北京100083

出　　处：《地质学报》2015年第12期2236-2249,共14页Acta Geologica Sinica

基　　金：国土资源部公益性行业科研专项课题(编号:201211005-1);国家自然科学基金(编号:41172150;41404070);中国地质调查局地质矿产评价专项工作项目(编号:12120113013600)资助

摘　　要：查明泥河湾盆地新生界及中生界地层序列及基底的分布与赋存形态是研究泥河湾盆地形成机制的基础性工作。本研究在泥河湾盆地桑干河与壶流河交接处附近采集了四条测线的反射地震数据,通过对精细处理后的地震剖面进行详细分析,在剖面上厘定了三个具有明显强反射标志的地层,即古近系的玄武岩、侏罗系上统的含煤地层和侏罗系下统的含煤地层;其中,新近系沉积层与古近系玄武岩界面在地震剖面上出现的双程旅行时为0.3-0.6s,深度范围为300-500m,而第四系泥河湾组底界由南西到北东逐渐加深,其界面深度为200-300m;侏罗系上统含煤地层在地震剖面上出现的双程旅行时在0.8s上下波动,其深度约为1200m,探测出侏罗系上统顶界面的深度范围为800-1100m;侏罗系下统含煤地层在地震剖面上出现的双程旅行时为1.0-1.4s,深度范围为1800-2000m,由此推测出中生界侏罗系与古生界寒武系地层分界线的深度为2000m左右;根据地震反射波阻抗差别推测出新元古界和太古界地层的分界面在地震剖面上出现的时间约为2.5s,其深度为4000m左右。本研究通过四条反射地震测线的数据基本上查明了泥河湾盆地位于探测区处第四系泥河湾组底界面的深度分布范围及起伏形态、侏罗系上统顶界面和下统底界面的大致埋深,为查明泥河湾盆地新生界及中生界地层序列提供了基础性的参考信息。An investigation into the stratigraphic sequences of the Cenozoic and Mesozoic Eras and the depth distribution of the bottom boundary of the Quaternary strata in the Nihewan Basin was implemented.In this paper we obtained the seismic data of four seismic survey lines close to the intersection point between the Sangan River and the Huliu River.After processing the seismic data and analyzing the four seismic profiles in detail,we found three seismic reflection interfaces with strong amplitudes,which may rearesent three different sets of strata,that is,the basalt strata of the Paleogene system,the coal-bearing strata of the upper Jurassic system and the coal-bearing strata of the lower Jurassic system.We deduced the interface between the bottom boundary of the deposit layer of the Neogene period and the basalt strata of the Paleogene system in the Nihewan Basin.The two-way-travel-time of the seismic reflection interfaces in the seismic profile is located in the range from 0.3to 0.6second and the depth of it changes from 300to500 meters.The bottom boundary of the Nihewan formation varies from 200 to 300meters and it becomes deeper and deeper from the southwest to northeast along the seismic profiles.We inferred that the twoway-travel-time of the coal-bearing strata of the upper Jurassic system in the seismic profiles was around0.8second and their depth is located around 1200 meters.Hence,the depth of the top boundary of the upper Jurassic system varied from 800 to 1100meters.The two-way-travel-time of the coal-bearing strata of the lower Jurassic system in the profiles were in the range from 1.0to 1.4seconds and their depths vary from 1800 to 2000meters.Therefore,the interface between the Jurassic and Cambrian systems is located around 2000 meters in depth.According to the differences of seismic wave impedances between the strata of the Proterozoic Era and those of the Archaeozoic Era,we found their interface is located around 2.5seconds in the two-way-travel-time axis and around 4000 meters in depth.In this paper we

关 键 词：泥河湾盆地 第四系底界面 地震测线 反射标志层 地震解释 波阻抗 

分 类 号：P534.5[天文地球—古生物学与地层学] P534.6[天文地球—地质学]