MECHANISTIC SOLUTIONS TO THE OPENING OF THE GULF-OF-MEXICO

Two mechanistic model-which are unlike the traditional plate-tectonic landfill models used for most proposed Pangea reconstructions of the Yucatan block-relate the Mesozoic opening of the Gulf of Mexico directly to the movement of the North and South American plates: (1) a previous piggyback model in which Yucatan moves with South America out of the western gulf and (2) a new edge-driven model in which the motion of the Yucatan block is caused by forces applied to its margins by the movement of the North and South American plates. In the second model, Yucatan moves out of the northern Gulf of Mexico as a gear or roller bearing. On the basis of magnetic edge anomalies around the gulf, this edge-driven model predicts that from the Bathonian to Tithonian (approximately 170 to approximately 150 Ma), Yucatan was rotated approximately 60-degrees counterclockwise as a rigid block between North and South America with rift propagation and extension occurring simultaneously in the Gulf of Mexico and Yucatan Basin.