辽西义县组尖山沟层沉积环境粒度分析

尖山沟层沉积剖面粒度分析结果表明该层为湖相由浅变深、湖体扩张的两个相似的正粒序沉积旋回组成,与内陆河流密切相关、离岸不远的半深湖深湖沉积环境。碎屑颗粒以递变悬浮方式搬运,沉积物按粒度大小和密度梯度成层分布,在流动中由下至上粒度逐渐变细。由于涡流发育及作用,使沉积物中基本没有滚动颗粒。受火山作用的影响,尖山沟层粒度分析参数与特征表现出与正常沉积相不完全一致性,呈现出独特的粒度分布规律。

Grain size analysis of sedimentary environment from Jianshangou bed of Yixian Formation in western Liaoning, China

Through the grain size analysis of sedimentary section of Jianshangou bed,the results reveal not only two similar sedimentary cycles with positive grain-sequence,which provide the evidences for the lacustrine from shallow to deep and the body extention,but also reveal offshore lacustrine facies from semi-deep to deep sedimentary environment correlated with inland rivers.The clast grains are carried in turn by suspension,and then it is not uniform that sediment stratifies by grain size and density grads.Thus the grain size gradually decreases from the bottom to the top in the course of flow.Because of the developed vortex and its action,there is not rolling-grain in the sediment basically.In view of volcanism influence,the parameters and features of grain size analysis are different from the normal sedimentary facies,and then take on special regularities of grain size distribution.