细粒沉积物搬运机理研究进展OA

[Significance]The study of fine-grained sediment transport mechanisms is an important part of the"source-to-sink"system theory of fine-grained sediments,and it is significant for the restoration of sedimentary envi-ronments,understanding the distribution of fine-grained sediments and predicting the distribution of unconventional oil and gas resources.Due to the fine grain size,which makes them difficult to observe,and the diversity of transport modes,each transport mode corresponds to particular sedimentary structures.Therefore,research on the transport mechanisms of fine-grained sediments has progressed slowly.From a review of the existing research reported in China and elsewhere,it is evident that there is still a lack of sorting and summarizing research findings regarding the trans-port mechanisms of fine-grained sediments.[Progress]This study synthesizes current research,systematically sorts the transport modes and sedimentary characteristics of fine-grained sediments and classifies the transport modes of fine-grained sediments into three major categories:physical transport,chemical transport,and biological transport.Physical transport includes river water,atmosphere,bottom current,density underflow,and six types of gravity-flow transport.River water and atmospheric transport rely on the forces exerted by water flow and/or wind to overcome the gravitational force on fine-grained materials.These are mainly traction force and load force.Bottom current,density underflow,and gravity flow transport are triggered by tides,wind,earthquakes,floods,storms,volcanic eruptions and other means,with gravity being the main driving force.Clay minerals,dissolved organic carbon,carbonate min-erals,iron minerals and others are transported as colloids or as true solutions.Dissolved substances are affected by environmental factors such as pH,Eh,temperature,pressure,and ion concentration or charge,and are transported by chemical means.Biological absorption and enrichment,environmental changes caused by biological activities and bioturbation all affect the formation and transport of fine-grained materials.[Conclusion and Prospect]Physical transport has diverse modes.With driving forces such as traction force,carrying capacity,and gravity,it can form a rich variety of sedimentary structures.Chemical transport mainly involves dissolved substances and is affected by en-vironmental factors such as pH values and temperature.Biological transport influences the transport of fine-grained substances through absorption and enrichment,alteration of the environment,and bioturbation.In the future,atten-tion should be focused on the interactions among the transport mechanisms of fine-grained sediments,the accuracy of identifying sedimentary structures should be improved,importance should be attached to simulation experiment re-search,and the quantitative analysis of chemical and biological effects should be strengthened,so as to enhance the understanding of the transport processes of fine-grained sediments and promote the development of the theory of fine-grained sedimentology.