内蒙古苏尼特左旗下二叠统哲斯组沉积组合类型及沉积序列演化

PATTERNS OF SEDIMENTARY ASSOCIATIONS AND EVOLUTION OF SEQUENCE OF ZHESI FORMATION IN SONID ZUOQI, INNER MONGOLIA

通过岩相类型、沉积组合、垂向序列分析等方面的研究，对内蒙古苏尼特左旗地区下二叠统哲斯组的沉积环境及沉积演化序列进行了讨论。认为哲斯组下段主要为冲积扇－辫状河沉积以及泻湖－水下扇重力流沉积；哲斯组上段主要为滨岸（潮坪）沉积、泻湖－水下重力流沉积以及浅海沉积。哲斯组由下段的陆相砂砾岩、砂泥岩转变为上段海陆交互相的碎屑岩夹少量碳酸盐岩反映了一个小的海侵过程。

he authors discuss the factes, factes associations and the evolution of sequence of Zhesi Formation in Sonid Zueqi, Inner Mongolia. Identification. and analysis of facies and facies associations together with vertical sequence enable the deposits of various sedimentary environments within Zhesi Formation to be recognized. The lower member of Zhesi Formation is mainly the assemblage of deposits of alluvial fan-braid river system and lagoon-subfluvial debris flow system, and the upper member of Zhesi Formation is mainly that of shore face (tidal)-lagoon -subfluvial gravity flow system and shallow marine system. The evolution of Zhesi Formation from continental deposits to mutual factes of sea and continent indicates a small transgressive process.