Experimental Studies of Cretaceous Transgressions for Africa

摘要

Cretaceous (Albian to Turonian) transgressions around the coast of Africa display a type of correlative pattern that suggests they may be the results of a see-saw motion. Although not immediately obvious on an inspection of available maps, a detailed bio-stratigraphic analysis of the ammonite associations supports this viewpoint. Scale models of the African continent were built, based on reconstructions of Early Cretaceous topography and structure, to simulate sequences of transgressions with different orientations of tilt of the continental plate. The first experiments were made with rigid models but later work has been done with flexible models, which allow the simulation of major tectonic events. The results show that very close approximations to known paleogeographic distributions can be obtained; particularly good results have been produced for Cenomanian-lower Turonian. The work is part of a project on the origin of the South Atlantic Ocean.