四川盆地西部上三叠统须家河组二段风暴岩沉积特征

CHARACTERISTICS OF STORM DEPOSITS IN UPPER TRIASSIC XUJIAHE FORMATION, SICHUAN BASIN

李华启 姜在兴 邢焕清 鲜本忠

Li Huaqi Jiang Zaixing Xing Huanqing Xian Benzhong

通过研究,发现了四川盆地西部上三叠统须家河组二段沉积具有典型的风暴沉积特征,主要包括渠模构造(或口袋构造)、冲刷面和截切构造、风暴滞积层段、丘状交错层理、包卷层理、浪成层理、倒“小”字状构造、生物扰动等。须二段的风暴沉积类似于鲍马序列,垂向沉积序列可以划分出Sa,Sb,Sc,Sd,Se等5段。风暴沉积是由风暴作用引起的强烈振荡风暴浪作用于三角洲、扇三角洲,使沉积物经搬运再沉积的产物。风暴岩沉积构造类型丰富多样,而又以风暴成因的泥砾为特征,泥砾的形态,排列样式,组合方式,反映了风暴沉积的强度和频度。须二段风暴沉积是四川盆地的一种新型储集层

Storm deposits has been found for the first time in the 2nd member of Xujiahe Formation ( Upper Triassic) in western Sichuan Basin.Based on the micro-facies of cores,the main types of tempestite sedimentary characteristics have been identified, including gutter cast, scouring surface, truncated structure, storm lag deposit, hummocky cross-stratification,convoluted laminations, V-shaped structures generated by wave. A detailed study of sedimentary structures and petrological features of storm deposits has been made, such as individual laminates,thickness of storm deposit, and so on. The storm deposits are characterized by their lithologic features, and storm sedimentary sequence are related to storm activity and similar to the typical Bouma sequence.The sedimentary environment of tempestites is discussed,and the storm sedimentary model is explored.

10.11743/ogg20030119