The Dongsha fault-uplifted massif (for convenience

Dongsha massif from here on) is located in the northern continental shelf-slope of the South China Sea

where the water depth is 100–400 m. The massif is considered to be a part of the large-scale fault-uplifted zone directed NE and separating the Pearl River Mouth Basin into northern and southern graben areas. The sedimentary cover of the Pearl River Mouth Graben consists mainly of a 7000–10000 m thick Tertiary system. A large-scale uplift occurred in the Dongsha fault-uplifted zone during Paleocene-Eocene

when the lower structural layer (lower Tertiary) existed only in the small depressions of the fault-uplifted zone. The formation and evolution of the Dongsha fault-uplifted zone could be divided into: 1) the base-ment formation stage (J2-K1); 2) the slowly uplifted stage (K2-E 2 2 ; 3) the weathering and erosion stage (E 2 3 -E 3 1 ) 4) the integrated subsidence stage (E 3 2 -N 1 2 ) and 5) the last uplifted stage (N 1 3 -Q). The formation of the oil and gas pools of the Dongsha massif was obviously controlled by the formation and evolution of the massif. In the region of the massif

there are good reservoirs and caprocks

many channels for gas-oil migration

and a series of structural and organic reef traps. In addition

because the massif is higher than its adjacent depressions

it became a major place where the gas and oil concentrate from the surrounding depressions. All the above factors are favorable for the formation of large oil-gas pools in the Dongsha fault-uplifted zone.