关键词: 白云凹陷, 东沙25凸起, 生长地层, 沉降史, 珠江口盆地, 油气

Abstract: Research on the uplifts tectonic history is significant for hydrocarbon exploration. This study aims to investigate the evolution of Dongsha (DS) 25 uplift in Baiyun sag, Pearl River Mouth basin, by integrating and comparing with growth strata, back-stripping technique and remnant tectonic subsidence approach associated with tectonic evolution. The growth strata in terms of the strata thickness variation, seismic reflections terminal geometry indicate that the development of the DS25 uplift could be divided into several main stages. Besides，resorting to back-stripping technique, we interpreted subsidence history of the DS25 uplift. Furthermore, by combining with estimation of remnant tectonic subsidence, the movement and development period of the uplift are accessed. By comparison with the above three methods, we integrated the major tectonic events interfaces deduced from growth strata, rapid or weak subsidence stages, the uplift ascending or subsiding movement etc., and presented that the DS25 uplift experienced following five stages. From 65 Ma to 30 Ma, the uplift suffered strong erosion. Before 30 Ma, the DS25 uplift underwent strongly uplift. From 30 Ma to 23.8 Ma, it experienced weak subsidence. From 23.8 Ma to 10.5 Ma, it subsided rapidly,which can be subdivided into three episodes according to different subsidence rates. From 10.4 Ma to present, the uplift was affected by the Dongsha movement and kept continuously ascending.

Key words: Baiyun sag, Dongsha 25 uplift, growth strata, subsidence history, Pearl River Mouth basin, petroleum