How the closure of paleo-Tethys and Tethys oceans controlled the early breakup of Pangaea

Abstract

Two end-member models have been invoked to accommodate the Mesozoic dispersal of the supercontinent Pangaea. In one end-member, the opening of the Atlantic Ocean is inferred to have been balanced by the closure of the Panthalassan Ocean related to subduction off the western margins of the Americas. In the other end-member model, the opening of the Atlantic Ocean is accommodated by the closure of the paleo-Tethys and Tethys oceans linked to subduction off the southern margins of Eurasia. Here, I re-evaluate global plate circulation data compiled for the middle Mesozoic Era. The present evaluation confirms that closure of the paleo-Tethys and Tethys oceans compensated for the early opening of the central Atlantic and proto-Caribbean oceans. This result implies that the tectonic evolution of the North American Cordillera was independent from the processes governing Pangaea breakup in the Jurassic and Early Cretaceous Periods. As well, the opening Atlantic and closing Tethys realm must have been tectonically connected through the Mediterranean region in terms of a transform fault or point yet to be factored into geological interpretations. Tight geometric and kinematic correlations evident between the opening Atlantic and closing Tethyan domains can be demonstrated, which are most readily explained if the forces causing Pangaea breakup were transmitted from the Tethyan domain into the Atlantic domain, and not vice versa. Thus, slab sinking-based forces produced during the evolution of the Tethyan subduction zones are hypothesized to have controlled the early Atlantic breakup of Pangaea.