东海北部外陆架MIS 6以来的沉积地层格架及古环境演化

利用最新采集的高分辨率浅地层剖面资料,结合SHD-1钻孔岩心资料,对东海北部外陆架MIS 6以来的地层结构进行了分析,建立了MIS 6以来的沉积地层格架,并对地层的地质年代进行了厘定。根据Octavian Catuneanu(2005)的层序地层学理论,研究区地层划分出海侵和高位体系域、下降期体系域、海退和低位体系域。研究表明,过孔的浅地层剖面与钻孔岩心的沉积地层有很好的对应关系。东海北部外陆架MIS 6以来可划分出7个不整合界面(D7-D1)和7个地震单元(SU7-SU1)。东海外陆架的海进层序与海退层序有规律地交替发育,它们与海平面变化曲线也有很好的对应关系。其中,地震单元SU1、SU5分别为MIS 1、MIS 5形成的海侵沉积,主要发育浅海沉积层,100 m以浅的位置发育潮流沙脊;地震单元SU2、SU4、SU6分别对应MIS 2、MIS 4和MIS 6低海平面时期形成的河流/河口-三角洲沉积;地震单元SU3、SU4为下降期体系域,这两个亚单元分别对应MIS 3和MIS 4晚期。MIS 4-MIS 3发育厚层且分布广泛的水下三角洲,但MIS 4发育的水下三角洲的规模不及MIS 3大。总之,对MIS 6以来沉积地层格架的建立和古环境研究可为东海外陆架晚第四纪地层的海平面变化、古环境演化等相关研究提供参考。

层序地层学与油气勘探和开发

一。

高分辨层序地层学在大庆长垣以东扶、杨油层地层界面识别的应用

本文对大庆长垣以东三肇凹陷扶、杨油层的岩性、矿物、地球物理特征综合研究,通过层序地层的研究进一步确立了长期有争议的扶、杨油层的地层分界。为建立该地区扶杨油层统一的地层沉积格架,建立了扶、杨油层组的划分标准,根据标准层、沉积旋回、沉积组合、测井曲线形态等对扶、杨油层界面进行了统一划分对比,为其河道砂体分布规律预测和未动用探明储量地区的开发提供了地质基础。

Sedimentary microtopography in sequence stratigraphic framework of Upper Ordovician and its control over penecontemporaneous karstification,No.I slope break,Tazhong,Tarim block

In order to reveal the relationship between the penecontemporaneous karstification and sedimentary microtopography in sequence stratigraphy,the sequence stratigraphic framework of Lianglitage formation in Upper Ordovician is studied according to the well drilling,logging,geophysical data,detailed observations of core and the paleontology.The Lianglitage formation belongs to the sequence Ⅳ of Ordovician.The second member of Lianglitage formation is prograde sedimentation in highstand systems tract,and is favorable for developing reef flat.The development scale and thickness of reef flat are controlled by the variation of secondary sea level.The types and characteristics of karst in the highstand systems tract show that the late highstand systems tract is dissolved and cemented by the meteoric fresh water and mixed water.Penecontemporaneous karstification is developed at the top of parasequence and high place of geomorphology.Atmospheric diagenetic lens is formed.The developing regulations and controlling factors of penecontemporaneous karstification can provide new clues to the prediction and exploration of favorable reservoir in this area.