Origin and Inversion of Sedimentary Basins in Southern Central America

摘要

The origin of southern Central America dates back into the middle Cretaceous. Since that time at least two successive island arcs developed in the area. Only at the beginning of the Pliocene did the last island arc become a land bridge between the two Americas. The architecture of the isthmus is structured by three regional angular unconformities of Campanian, Okogocene, and latest Miocene ages. These unconformities form the boundaries of the basin fills of the Paleogene and Neogene island arcs. The Campanian unconformity probably was the result of the establishment of a new subduction zone in the rear of a drifting oceanic plateau as a consequence of its blocking the gap between the two Americas. The Oligocene and latest Miocene unconformities most probably were caused by the subduction of rough reliefs on the downgoing slab comparable to (and probably larger than) the present-day Cocos Ridge.