准噶尔盆地南缘新近系层序类型与发育模式研究

Research on types and development models of Neocene sequences at southern margin of Junggar Basin

潘春孚 纪友亮 高志勇 朱如凯 朱健湖 俞国鹏 胥猛

中国石油大学(北京)地球科学学院;中国石油勘探开发研究院;东方地球物理公司新疆地质调查处;西部钻探工程有限公司吐哈录井工程公司;

1.College of Geosciences, China University of Petroleum, Beijing 102249, China; 2.Research Institute of PetroleumExploration & Development, PetroChina, Beijing 100083, China; 3.Xinjiang Geological Survey, BGP, Urumqi 830016, China; 4.Tuha Mud Logging Company,Western PetroleumDrilling and Exploration Engineering Company, PetroChina, Shanshan 838202, China; 5.Well Testing Company, Xinjiang Oilfield Company, PetroChina, Karamay 834000, China

准噶尔盆地南缘第三纪—第四纪为前陆盆地再生阶段。在前人对准噶尔盆地南缘层序地层学研究成果的基础上,充分利用野外露头、钻测井等资料,将准噶尔南缘新近系沙湾组和塔西河组地层划分为1个二级层序,2个三级层序。依据准噶尔南缘前陆盆地构造演化的不同阶段及其形成机制,将2个三级层序分别归纳为构造层序和气候层序2种类型,每类层序内部均可划分为低水位体系、湖侵体系域和高水位体系域。构造层序发育受逆冲构造作用影响明显,气候层序发育主要受气候引起的相对湖平面变化影响。依据2种层序内部结构发育的特点结合山前带所处盆地的特殊构造部位及层序发育演化阶段的不同,将准噶尔盆地南缘新近系层序发育模式总结为陡坡型和气候型。

Tertiary and Quaternary of the southern margin in Junggar Basin is the period of rejuvenated foreland basin. On the basis of the research outcomes of sequence stratigraphy at the southern margin of Junggar Basin, Neocene Shawan Formation and Taxihe Formation were divided into one second-grade sequence and two third-grade sequences full taking use of the field outcrop, drilling and logging. According to the different stages of tectonic evolution and their corresponding deposition composition, two sequences were generalized to two types, which were tectonic sequence and climate sequence. The inner of every sequence type may be divided into lowstand system-tract, transgressive system-tract and highstand system-tract. The development of tectonic sequence is obviously influenced by the thrust tectonism and the development of climate sequence is mainly influenced by the change of relative lake level which is caused by the climate. Based on the characteristics of the inner contexture development of two types sequences, and combined with the special tectonic location where the foothill belt lies and the different evolution stages of sequence development, the development models of Neocene sequence at the southern margin of Junggar Basin are summarized as the steep slope type and climate type.