| The contractional structure in muds, which is a typical tectonic pattern of the gravitational decollment thrust structure in the deepwater area of Niger Delta Basin, is mainly composed of thrust faults, plastic mud structures and associated folds and normal faults. Based on the interpretation of seismic data, it is considered that the contractional structure is mainly controlled by plastic mud structure. On the tectonic history, the contractional structure began to form in the late Tortonian of the Miocene, and in the Messianian-Zanclean reached the strongest, then the tectonic activity gradually weakened, but still active. Based on the analysis of paleo-structure restoration and sedimentary system, it is believed that the late Tertonian tectonic activity begin to control the sediments. The upper part of the Tertonian and its overlying strata are of obvious syn-deposition. As to the thrust fault, the thickness of hanging wall is clearly smaller than that of footwall, and as to the associated fold, the thickness of the strata of wings is larger than that of the top of anticline. |
