砂岩侵入复合体的建筑结构要素及其特征

砂岩侵入复合体是指沉积砂质母岩,在未固结时由于某种机制而积累了异常高压,产生液化、流化、再活动,向上覆细粒沉积物侵入的各种砂体的总和。目前已经在全球50多个深水盆地中(Braccinietal,2008)及所有的年代地层中都发现了从毫米到千米级别的砂岩侵入体。砂岩侵入复合体包含母岩、侵入体系和喷出体系三部分,通过对目前报道的一些砂岩侵入复合体实例分析,对其各建筑要素的外部几何形体和边界特征、内部沉积构造和显微结构进行了总结。不规则的几何形态,突变的边界特征,与液化作用相关的无构造砂岩、碟状构造、管状构造以及独特的泥岩碎屑表现出来的粒序性、条带等沉积构造,形状各异的矿物颗粒以及泥岩碎屑中砂岩裂缝切割等显微结构都可以作为识别砂岩侵入复合体的标准。加强砂岩侵入复合体的研究,为侵入圈闭的勘探和开发提供理论基础。

Architectural Elements and Characteristics of Sand Injectite Complex

Sand injectite complex is the sum total of some injected sand bodies which are formed by liquefaction, fluidization, remobilization and injection upward into the overburden of unconsolidated sand, in certain trigger machanism. They are recognized in about 50 deep water basins globally, and throughout the stratigraphic record, which range from millimeter to kilometer in scale. Sand injectite complexs have a tri-partite organization: parent sandstone units, intrusive complex and extrusive complex. Based on the analysis on the examples from the published papers, the characteristics of geometry and margins, internal sedimentary structures and microtextures of architecture elements are summerized. Irregular geometries, sharp margins,internal sedimentary structures associated with liquefaction, such as structureless sandstone, dishes, pipes and special mudstone clasts and rhythms, banding, mineral grains and mudstone clasts with sandstone filled micro-fractures are all helpful to identify the elements of sand injectite complex and provide the theory basis for exploration in intrusive traps in future.