Seismic Identification And Evolution Of Mass Transport Deposits In The North Slope Of South China Sea

A lot of large mass transport deposits (MTDs) have been discovered in the Quaternary strata according to recent geological and geophysical investigation results. MTDs are very popular sedimentary system in the continental slope, which include slides, slumps, and debris flows and other gravity current process. MTDs as specific geological phenomena in deepwater of continental margins which play an important role in research of earth“Source to Sink”.As everyone knows, MTDs as one of the important geological hazards which can hurt the deepwater equipments and induce tsunamis. At the same time, MTDs have close relationship with formation of deepwater hydrocarbon and gas hydrate. MTDs usually are good seal for deepwater because of its lower porosity and permeability, and could be reservoirs if the slumps are originally good sandstone. Thus, the research of MTDs is essential for deep-water sediment transport mode study and deep-water oil & gas accumulation in our country.The area of MTDs in the continental margin in the deepwater area of the northern margin of the South China Sea exceed tens of thousands of square kilometers, this paper research of MTDs bases on seismic data, well data and areal geology data. MTDs in the continental margin in the north of South China Sea can be divided into 3 structures (headwall, body and toe). On the seismic profiles, MTDs show three complex seismic facies which are : (1) rotation or slump block, existing primary sedimentary level and reflecting extension and lateral transport; (2) thrust block, reflecting the internal deformation; (3) complex reflection usually developed in the lower of the MTDs with intensive deformation and no primary strata. Besides, this paper analyzed the deposition characteristics of MTDs in the deepwater area of the northern margin of the South China Sea. Last, through the research of regional geological data of the northern margin of the South China Sea, revealed the evolvement of MTDs in the continental margin in the north of South China Sea.