The Gulf of Mexico and Canada Basin: Genetic Siblings on Either Side of North America
The Gulf of Mexico and Canada Basin are small oceans located in back-arc settings of the Paleo-Pacific Ocean, at the northern and southern tip of the North American craton. Both are pronounced rotational, pie-shaped basins, with their distal ends bounded by major transforms, and both opened by ~70° counter-clockwise rotation of micro-continents away from the craton. While they formed synchronously with elements of the Central and North Atlantic, their oceanic crust never connected with that of the Atlantic. Both oceans were periodically confined, with important implications for the paleo-environment and petroleum system. Their North American affinity resulted in a number of intriguing similarities, such as timing and magnitude of main sediment influx. We argue for a genetic relationship between the geometry and kinematics of these pie-shaped oceans, their proneness to confinement, and their back-arc setting. In contrast to common back-arc basins, the Gulf of Mexico and Canada Basin had spreading ridges oriented nearly orthogonally to the Paleo-Pacific subduction direction. This distinctive high-angle back-arc development may be due to “Wilson Cycle” reactivation of orogenic belts intersecting the Paleo-Pacific margin, and/or to interaction between descending slabs beneath adjacent cratonic masses, and may apply to other examples worldwide, such as the South China Sea.
Manuscript received 30 Nov. 2015; Revised manuscript received 13 June 2016; Manuscript accepted 18 June 2016