高校地质学报2018，Vol.24Issue(3)：425-432,8.DOI:10.16108/j.issn1006-7493.2017111
松辽盆地古龙凹陷泉头组坡折带特征及其对沉积层序的控制作用
Characteristics of the Slope Break Belt and Its Control on the Depositional Sequence: the Quantou Formation of the Gulong Sag, Songliao Basin
摘要
Abstract
Based on data analyses of seismic, well drilling, logging, and stratigraphic correlation and thickness, we conduct an in-depth investigation of the slope break belt in the Quantou Formation, Gulong sag, Songliao Basin. Results show that there are three types of belts in the study area, i.e., fault slope-break belt, flexural slope-break belt and depositional slope-break belt. The slope-break belts distribute in a north-south arc pattern along the Yingtai nose-shape structure of the west of the Gulong sag. Average gradient of the belt ranges from 19‰ to 50‰. The development of the slope break belt controls the structures of sedimentary sequence and the sedimentary environment. The fault slope break belt develops at the bottom of the sequence, and controls the development of the SQ11 aggradation sequences of fluvial facies. It is characterized by that the thickness of the lower sequence is 2 times that of the upper sequence. The flexural slope-break belt develops in the middle of the sequence, and presents a two-section feature of the gentle slope belt (α) and the steep slope belt (β). The fourth order sequence SQ21developed dense onlap points in the slope belt, forming a lacustrine onlap sequence structure. The thickness of the strata in the two sides of the slope belt is characterized by thinner upper part and thicker lower part. The depositional slope-break belt distributes on the top of the sequence, which controls the development of the fifth order sequence SQ22-1, forming a progradation sequence of laucustrine delta facies. Its thickness is characterized by thinner lower part and thicker upper part. The fault slope-break belt controls the aggradation sequence of fluvial facies, which is beneficial for the development of traps with upward-dip sheltering by fault and point-bar lens. The flexural slope-break belt controls the lacustrine onlap sequence, which is beneficial for the development of lithologic traps that are characterized by the styles of updip wedge-out. The depositional slope-break belt controls the progradation sequence of lacustrine delta facies, which is beneficial for the development of the mouth bar lithologic traps. Therefore, the study of the slope-break belt is of significance to the oil and gas exploration in the Gulong sag of the Songliao Basin.关键词
松辽盆地/古龙凹陷/坡折带/层序与沉积Key words
Songliao Basin/Gulong Sag/slope break belt/sequnce and sedimentation分类
天文与地球科学引用本文复制引用
王一同,张顺,林春明,杨知盛..松辽盆地古龙凹陷泉头组坡折带特征及其对沉积层序的控制作用[J].高校地质学报,2018,24(3):425-432,8.基金项目
"973"项目"白垩纪地球表层系统重大地质事件与温室气候变化"(2006CB701400)资助 （2006CB701400）
