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.