Rifting and the Evolution of a Marginal Basin, in Continental Rifted Margins 2
Résumé
Marginal basins are basins opened at the border of continental margins. Due to their moderate size, they allow more accurate observation of rifting and continental breakup processes than large oceans. Because their conjugate margins are close enough, precise correlations can be done, and boundary forces (e.g. free edge) are easier to identify. Among the most studied marginal basin, the South China Sea (SCS) which is not a back-arc basin, is a good example to illustrate how the initial conditions, which shaped the geometry of the margins, are important. The evolution of the rifting, the spreading and the cessation of rifting of this basin seem to be controlled by the effect of several structural parameters. Among these are the intrinsic structure of the continental crust inherited from the earlier structures, the thermal state and crustal thickness, and above all the V-shaped geometry of the basins which reflects along strike variation of the shear strain with time, which in turn has severe implications on the subsidence history.