Permo‐Triassic reconstruction of western Pangea and the evolution of the Gulf of Mexico/Caribbean region

Abstract

A Permo‐Triassic reconstruction of western Pangea (North America, South America, Africa) is proposed that is characterized by (1) definition of the North Atlantic fit by matching of marginal offsets (fracture zones) along the opposing margins, (2) a South Atlantic fit that is tighter than the BuIlard fit and that is achieved by treating Africa as two plates astride the Benue Trough and related structures during the Cretaceous, (3) complete closure of the Proto‐Atlantic Ocean between North and South America, accomplished by placing the Yucatan block between the Ouachita Mountains and Venezuela, (4) a proposed Hercynian suture zone that separates zones of foreland thrusting from zones of arc‐related magmatic activity; to the northwest of this suture lie the Chortis block and Mexico and most of North America, and to the southeast lie South America, the Yucatan Block, Florida and Africa, and (5) satisfaction of paleomagmatic data from North America, South America, and Africa. Beginning with the proposed reconstruction, the relative motion history of South America with respect of North America is defined by using the finite difference method. Within the framework provided by the proposed relative motion history, an evolutionary model for the development of the Gulf of Mexico and Caribbean region is outlined in a series of 13 plate boundary reconstructions at time intervals from the Jurassic to the present. The model includes (1) formation of the Gulf of Mexico by 140 Ma, (2) Pacific provenance of the Caribbean plate through the North America‐South America gap during Cretaceous time, (3) Paleocene‐Early Eocene back arc spreading origin for the Yucatan Basin, whereby Cuba is the frontal arc and the Nicaragua Rise‐Jamaica‐Southern Hispaniola is the remnant arc, and (4) 1200 km of post‐Eocene cumulative offset along both the Northern and Southern Caribbean Plate Boundary Zones, allowing large‐scale eastward migration of the Caribbean plate with respect to the North and South American Plates.