Fig. 5. Metamorphic core complexes (MCCs) of the northern South China Sea showing characteristic folded detachment fault, crustal-scale nappe folds, migmatite- and/or pluton-cored domes.

a Three-dimensional block diagram illustrating the detachment surface and the footwall deformation associated with the faulting process. Note that the doming of the detachment includes N–S and E–W corrugations. Intrusives and nappe folds verge to the south along the southward shearing of the detachment. b Conceptual sketch cross-section parallel to the extension direction showing the highly extended continental crust and the ocean–continent transition. Upper crust boudinage in the highly extended continental margin evolves down-dip into the ocean–continent transition (OCT) and oceanic lithosphere.