Evolution of the Continental Margin of South to Central Vietnam and Its Relationship to Opening of the South China Sea (East Vietnam Sea)

Abstract

The continental margin of Indochina represents the westernmost margin of the South China Sea, a wide continental rift that in the west is mostly submerged. In the region of south to central Vietnam, the location of this study (Figure 1), the continental margin extends offshore for >100 km before oceanic crust is reached. The extension that led to continental break-up has yet to be fully explained but is known to be related to the subduction of the paleo-Pacific plate, which at the time formed a wide Cretaceous magmatic arc with widespread calc-alkaline magmatism across south to central Vietnam and southern China. Subduction was directed to the northeast beneath southern China and westwards below Vietnam, the eastern margin of the Indochina block (Hall, 2012;Hennig-Breitfeld et al., 2021;Zhu et al., 2004).Extension is imprinted on the landscape and geology of Vietnam but to what extent is not yet clear. It also remains uncertain as to when surface uplift took place. Was uplift staggered over a long time or did it occur within a short

Geological Distribution of the Miocene Carbonate Platform in the Xisha Sea Area of the South China Sea, and Its Implications for Hydrocarbon Exploration

“…The chloroform bitumen "A" contents are 1.78% to 4.16%, with medium-to-good quality. The hydrocarbon generation threshold values of the source rocks are 1900-3100 m, having now essentially entered the gas-generation stage and even the mature stage of oil generation in most of the western region [38]. Another set of source rocks of the Lower-Middle Miocene developed during the continuous transgression stage.…”

Formation Mechanism of NW-Trending Faults and Their Significance on Basin Evolution in Zhu III Depression of the Pearl River Mouth Basin, SE China

“…In the Cenozoic, the East Asian Continental Margin developed intense rifting, producing massive rift basins and marginal seas. Among these, the South China Sea (SCS) and adjacent continental margin have attracted attention due to the obscure opening mechanism and strong lithospheric thinning [7][8][9]. As a representative of the epicontinental rift basin in the northern margin of the South China Sea (NSCS), the Pearl River Mouth Basin (PRMB) is an ideal study area for a better understanding of the tectonic evolution of the South China Block and the time limit of the opening of the SCS.…”