混合沉积研究进展与展望

混合沉积从一种“小众”的沉积类型，自20世纪50年代进入人们的视线，经过众多学者的研究，发现这种现象在海相、陆相以及过渡相等各类环境中均有一定分布，认为混合沉积物与硅质碎屑岩和碳酸盐岩属于同一个连续统一体，混合沉积是一种广泛的沉积类型。在前人研究的基础上梳理总结混合沉积相关概念，区分了不同类型、不同尺度的混合沉积。混合沉积形成过程主要包括高强度事件引发的间断混合沉积、相边界渐变接触形成的相混合沉积、原地死亡的钙质生物组合形成的原地混合沉积、构造边界遭受剥蚀形成的母源混合沉积等四种类型。混合沉积的形成受气候、构造、海（湖）平面相对变化、水动力、风场等多个因素的控制，且不同环境下主控因素不同。目前仍有一些问题亟需解决，如各组分在混合沉积物形成过程中的相互作用，多组分型混合沉积物与硅质碎屑—碳酸盐混合沉积物间的差异，混合沉积物复杂岩性测井识别，深水混积细粒层序划分，不同沉积环境混合沉积模式的适用性，混合沉积成岩演化序列的恢复等。这些方面的研究，对沉积动力学分析、完善深水混积细粒层序理论，恢复古环境、复建沉积过程，明确沉积体系展布，预测优质储层分布，指导非常规油气勘探开发等有着重要意义。

Research Advances and Prospect of Mixed Deposition

Mixed deposition has been in the limelight since the 1950s from a'niche'type of sedimentation.After many scholars'researches,mixed sediments are widely distributed in marine,continental,transitional sedimentary and all kinds of environments,which indicates that the mixed sediments and siliciclastic rocks and carbonate rocks belong to the same continuum,and mixed deposition is a kind of widely existed sedimentary type.On the basis of previous studies,this paper summarizes the concepts related to mixed deposition and distinguishes the different types and scales of mixed deposition.In terms of the formation process of mixed deposition,four types of mixed deposition models proposed by Mount are discussed in detail.The four types include intermittent mixed deposition caused by high intensity events,gradual contact of phase boundaries,in-situ calcareous biological assemblages,denudation of tectonic boundaries.The formation of mixed deposition is controlled by climate,tectonics,the relative changes of sea(lake)plane,hydrodynamics,wind field and so on.The main control factors are different in all kinds of environments.There are still some problems need to be solved,the interaction between the components in the formation of mixed sediments,the differences between multicomponent mixed sediments and mixed siliciclastic-carbonate sediments,complex lithology logging identification of mixed sediments,sequence division of mixed fine sediments in deep water environment,applicability of mixed deposition models in different sedimentary environments,restoration of the evolutionary sequence of mixed sedimentary diagenesis.The studies of these aspects have great significance on improving the dynamic theory,improving the sequence theory of mixed fine sediments in deep water environment,restoring mixed sedimentary paleoenvironment,reconstructing the mixed deposition process,clarifying the distribution of mixed sedimentary systems,predicting the reservoir spatial distribution,guiding unconventional hydrocarbon exploration and development in mixed sedimentary reservoirs and so on.