145 / 2014-09-06 18:33:49

Analysis On The Mechanism Of "joint Controlling Of Fault And Uplift" In Huizhou Sag, Pearl River Mouth Basin

Huizhou sag，Paleogene，“joint control of fault and uplift”

Structure pattern of uplifts and sags is the common rule in the development of rift basins. In a long period, the boundary faults, as the main controlling factors of the development and structure of a rift basin, were obtained a set of theories in fault-controlled depression that basing on a great deal of work. Structural factors, such as upliftas slope belt, was focusedmainlyon the influence on sedimentary system, sequence configuration development, and the favorable zone of hydrocarbon migration, etc. Very few studies have discussed what role of uplift playing on the evolution of a rift basin and how it have controlled the basin’s structure characteristics. We, trough the study on the structural of Huizhou sag in Pearl River Mouth Basin (PRMB), have found that it’s a unique sag with frequent changes of strike and trend, particular distribution of “uplifts and sags “style, and multiply structural styles. Uplifts with different levels, patterns andmechanism, in addition to faults, also have acted an important role in the process of the formation and development of Huizhou sag. Therefore, faults and uplifts should be researched as a whole, in order to investigate the role and controlling mechanism was played on the formation and evolution of Huizhou sag.
Fault and uplift as the two basic factors to control sag (depression), brought a series of changes on the structure and distribution of depression. Due to the different of their size and distribution, roles, the degree of control in various faults and uplift were forming a variety of structural styles and spatial distribution of depression within Huizhou hydrocarbon-rich sag. Therefore, “Joint control of fracture and uplift” control vertical and horizontal spatial forms, structural styles of depression that is inevitable, namely "control sag". “Joint control of fracture and uplift” play an important controlling role on the distribution, form, spatial separation and evolution of sag (depression)
Fault, combined with uplift, controlling a depression will defined the sequence architecture style, sedimentary-filling and sand body distribution of a depression,that is, architecture style, source and sand controlling. Architecture style controlling refers to the unique sequence stratigraphic configuration, sequence architecture style under the united function of faults and uplifts.Source controlling means to scattered source and different main source, such as fault-steep slop, uplift-gentle slop, steep and gentle slops in transfer zones, and the axial source, and so on. Sand controlling points to the controlling effects what faults and uplifts played on the development and distribution of sand body, including fault-steep slop subaqueous fan, transfer zone delta, uplift-gentle slop delta, low-uplift beach-bar sandstone, and other channel sand ,turbidite body.