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Abstract: Mesozoic and Cenozoic Plate Tectonic Setting of the Foldbelts of Northwestern South America

I. O. Norton, E. D. Goodman, A. R. Green

Mesozoic tectonic evolution of northern South America was dominated by Jurassic rifting of North America, the Mexico-Mayan blocks and possibly Chortis. Grabens on South America formed in this rift event trend northeast-southwest, following basement grain established during Paleozoic continental collision between North and South America. In Cretaceous time, a passive margin facing the proto-Caribbean formed on South America. Carbonate and clastic sediments forming a wide passive margin wedge prograded over the South American continental margin. Arrival of the Caribbean Plate in Late Cretaceous time only affected the northern margin of South America; the Pacific margin remained tectonically inactive until Oligo-Miocene time. At this time, a plate reorganization in the Pacif c resulted in reactivation of the Pacific margin of Ecuador and Colombia. Jurassic grabens were reactivated as strike slip fault zones which moved the Bonaire Block several hundred kilometers to the northeast. Near the end of Miocene time, another Pacific plate reorganization resulted in a change from strike slip to east-west compression along South America. This caused final uplift of the Andes mountain ranges. The influence of these tectonic events on sediment deposition and hydrocarbon play parameters will be discussed in this paper.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela