The tectonic types of the Zhujiang (Pearl) River Mouth Basin in the South China Sea are epicontinental rift-depression basins.Prior to Early Cretaceous time, the Dongsha Uplift arid its surrounding depressions had been combined with the Eurasia Plate in a single unit.Many ENE-trending narrow rifted basins were formed in the third episode of Yanshan orogeny (Late Laramide).The rifted basins in the Paleocene and Eocene were stretched and extended, forming Zhu 1, Zhu 2 and Zhu 3 depressions.The Dongsha Uplift is located between Zhu 1 and Zhu 2 depressions.covering an area of 28 000 Km2.Its geologic evolution can be divided into four stages: (1) Late Cretaceous-Paleocene block-faulting stage. (2) Eocene-Oligocene uplifting and eroding stage. (3) Late Oligocene-Early Miocene sustained subsiding stage. (4) Middle Miocene-Recent noncompensated subsiding stage. The Dongsha Uplift is a structural zone favourable for oil-gas accumulation.
The paper deals with the question of Holocene transgression on the southern plain of the Changjiang Delta. At the beginning of the transgression, the paleovalleys of the Changjiang and Qiantang Rivers were covered by sea water at first.The shoreline of 8000-7500 yr BP coincided with the -7m isobath of paleotopography.Sea level had already been the present level about 7000-6500 years ago, and the Holocene transgression reached its maximum extent.During the period, the Changjiang and Qiantang Rivers and the Dongtiaoxi valley were turned into estuaries; the eastern area of Shanghai became a shallow sea; some of the bays and lagoons were distributed on the Hang-Jia-Hu and Tao-Ge Plain; the hilly region around the Taihu Lake was coastal marsh and freshwater swamp.Gangshen on the west of Shanghai was formed 7000-4000 yr BP, and during the last 4000 years, the eastern coastal plain of Shanghai advanced quickly toward the sea, and partial clear land of the western Taihu Lake was enclosed and charged into a freshwater lake.
This study introduces a type of self-developed, GPS-based, simple and cheap Surface Current Experiment (SUCE) drifters designated for observing surface coastal currents. By examining trajectories of six drifters deployed in the Daya Bay and the drifter-derived velocities, we conclude that such drifters are generally capable of capturing the characteristics of wintertime surface coastal currents along the Guangdong coast.