【摘要】 大量的地质资料表明,渤海湾地区下第三系断陷式凹陷中有着发育的重力流沉积。沉积物主要由陆源碎屑组成,其它的再沉积碎屑组份有鲕粒、化石碎屑、植物碎屑和海绿石等。重力流沉积作用的机制包括洪水类型和滑塌类型。地理环境方面,在陡岸、缓岸和深水平原均有重力流沉积。形态上有扇形和层状两种类型。笔者认为这种浊积扇采用“湖底扇”一词更为适宜,因为海底扇一词经常指示一个相当大的范围。 深水碎屑岩由典型的浊积岩(或传统的浊积岩)、块状砂岩、卵石质砂岩、颗粒支撑砾岩和杂基支撑岩层(包括泥石流、卵石质泥岩和滑塌岩)组成。浊积岩沉积在正常的湖相暗色泥岩之中。 湖底扇浊积岩中有一系列的沉积构造,诸如鲍玛序列、粒序层理、垂向液化逃逸管、碟状构造、撕裂屑、重荷构造、包卷层理和槽模等。更多还原

【Abstract】 A lot of geological data indicate that a large amount of turbidites were developed in Eogene faulted depressions of Bohai Bay area.The main sediments are made up of terrigenous clastic deposits. Other resedimented clastic constituents are: ooid, fossil clasts, plant clasts and glauconite,etc.The mechanism of sedimentation includes flood type and slump type. With respect to the geographic settings,the turbidites were deposited in steep-bank,gentle-bank and deep-water plain, and there are two types of turbidites: fan-shaped and stratified.The authors consider it more appropriate to use the term "sublake-fan" for this lake facies sedimentation, because the submarine-fan often suggests a considerably larger scale. The deep-water elastics consist of classic turbidites, massive sandstone, pebbly sandstone,clast-supported conglomerate, and matrix-supported beds (including debris flows, pebbly mudstone, slumps). Turbidites were deposited in the dark shale of normal lake facies.There are a series of sedimentary structures in turbidites,such as Bouma sequence,graded bedding, vertical fluid-escape tubes, dish structures,rip-up clasts,load structures, convolute bedding, slump structures and flute marks, etc.更多还原