吐哈盆地台北凹陷侏罗系层序地层及聚煤特征

STUDY ON THE SEQUENCE STRATIGRAPHY OF JURASSIC IN TAIBEI SAG, TUHA BASIN

  • 摘要: 运用地表露头、测井曲线和岩心相结合的方法,分析了吐哈盆地台北凹陷侏罗系层序地层特征,将侏罗系划分为3个一级层序、7个二级层序、13个三级层序。每个三级层序中,湖侵体系域由退积的准层序组成,高位体系域由进积的准层序组成,由退积作用向进积作用的转换过程形成了加积的准层序组,低位体系域在本区不发育。研究发现,同一沉积体系在不同体系域内相序不同,三角洲沉积体系在高位体系域内是正常相序,而在湖侵体系域内是"顶底倒置"的相序。稳定的厚煤层在湖侵体系域内比高位体系域内更为发育。

     

    Abstract: The sequence stratigraphy of Jurassic in Taibei sag,Tuha Basin,is analyzed based on the comprehensive method of outcrop, logging and core analyses. The Jurassic has been divided into three first-order, seven second-order and thirteen third-order sequences. In each third-order sequence, TST is composed of regressive parasequence sets, HST is composed of transgression paracsquence sets, and the accretion parasequence sets were formed in the process of transform from regression to transgression, and LST is poorly developed in this area. Studies revedaled that the same sediment system has different facies sequence in different system tract. Delta sedimentary system shows normal facies sequence in HST, but shows inverted facies sequence in TST. Persistent thick coal beds are developed better in TST than in HST.

     

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