【摘要】 通过对鄂尔多斯盆地上三叠统延长组野外露头、岩心剖面的细致研究,发现深湖区发育有类型多样的同沉积变形构造。露头剖面中见有同沉积砂岩墙、砂泥岩脊、砂岩脉、微断层和褶皱变形构造等,岩心中也观察到砂岩揉皱构造,砂泥质角砾,微断层和砂岩脉等变形构造,在对其特征描述和层系结构分析的基础上,结合三角洲前缘砂体向深湖区滑塌形成富含火焰状构造的鲍马层系,指出同沉积构造成因与古地震作用关系密切。时间上同沉积变形构造与火山灰沉积物几乎同期发育,相伴而生,且略早于广泛发育的长7浊积岩;古地震、邻区火山作用或深部热作用导致盆地基底沉降、山体隆升,有利于滑塌浊积岩的形成。空间上同沉积变形构造主要分布于盆地南部和西南部,并且从南西至北东方向有强度减弱的趋势。综合对比同期周邻造山带的演化历史及深湖区同沉积变形构造的分布特征后认为,同沉积变形构造是对盆地南部秦岭碰撞造山和盆地内深部热作用的耦合响应,指示了深湖盆发育期对应于盆地构造相对活动的动力学背景,对同期优质烃源岩的发育有重要贡献。更多还原

【Abstract】 Various synsedimentary deformation structures are found in deep lake zone through detail study on outcrop and core sections of Upper Triassic Yanchang Formation in Ordos Basin.Syndepositional sandstone dikes,ridges,veins,minor faults and folds are found in outcrops section;Sandstone rumpled structures,sand muddy breccia structures,minor faults and sandstone veins are found in cores,based on the detail descriptive characteristics and analysis these structures of sequence,we propose a paleoseismic trigger to explain the various synsedimentary deformation structures,and the paleoearthquakes induced sand body at delta front along slope slump,a lot of flame structures and Bouma sequence are found.Detailed study of its distribution characteristics of that seismites and volcanic ash sediments in temporal is almost the same period in development;Slump turbidite formed after seismites and volcanic ash sediments,indicating that earthquakes,volcano eruption or deep thermal effect led to the basin basement subsidence,increasing in terrain elevation and later seismic prompted the formation of turbidites.Synsedimentary deformation structures are mainly locating in south and southwest of Ordos Basin,and the intensity decreased from southwest to northeast.Comprehensive comparison the same period adjacent orogenic belt evolution and the distribution characteristics of synsedimentary deformation structures in deep lake,suggest synsedimentary deformation structures coupled response of the Qinling collision orogenic process and deep heat effect,indicating a deep lacustrine corresponds to the basin with a relative activity dynamics setting,which played an important role in development of high-quality hydrocarbon source rocks.更多还原