Prevalent deep-water mass-transport deposits (MTDs) are important components of sedimentary formation on continental margins around the world.A systematic study on the depositional system is helpful to deeply understanding deep-water transport process

opening up new deep-water plays and reducing risks of offshore engineering facilities.Based on an literature review

deep-water MTDs refer to assemblage of all underwater gravity flow deposits except for turbidite deposits.They can be structurally segmented into three parts

namely head

body and toe.Besides

they can be divided into different types according to transport processes and sediment origins.Sediment gravity flow conditions are essential for deep-water MTDs to form

and their deformation processes should conform to the characteristics of Bingham Plastics.These depositional systems have different scales and contain various kinematic indicators

which can be generally recognized by using seismic

core and well logging data.Deep-water MTDs can form both seals and reservoirs

thus are potential exploration targets in deep-water area.A comprehensive analysis indicates that many problems still exist in the study of deep-water MTDs.For example

(1) the understanding of deep-water mass-transport process should be further deepened and unified;(2) the study on their forming conditions in different settings should be strengthened;(3) the differences between deep-water MTDs and turbidites should be more thoroughly understood;(4) the differences and commonalities between ancient and modern deep-water MTDs should be clear;and (5) the understanding of lithofacies types and lithofacies associations should be unified.It is proposed that future studies should focus on:(1) multi-scale characterization with data of multiple sources;(2) forming conditions

especially triggering mechanisms;(3) integrated research of underwater mass transport mechanism

deposit composition and deep-water gravity-flow deposits;(4) forming conditions of source

reservoir or cap rocks;(4) fine description of ancient deep-water MTDs;and (5) assessment on erosional ability and geological risks.