Amasia and Supercontinent Formation by Orthoversion

Abstract:

Traditional models of the supercontinent cycle predict that the next supercontinent—‘Amasia’—will form either where Pangaea rifted (the ‘introversion’ model) or on the opposite side of the world (the ‘extroversion’ models). In contrast, a new model termed “orthoversion”, predicts a new supercontinent will form 90° away from the previous one, somewhere along the subduction girdle encircling its predecessor. As continents are expected to aggregate over mantle convective downwellings, orthoversion predicts that a continent central to the assembling supercontinent would plot 90° away from the center of the dispersing continent. Supercontinent centers can be quantified by identifying the long-lived axis of oscillatory true polar wander associated with each supercontinent cycle; measuring the angle between two successive true polar wander axes allows one to test between the various models (0˚, 90˚, or 180˚) of supercontinent formation. The past three supercontinents (Pangea, Rodinia, and Nuna) appear to follow the 90° “orthoversion” model closely. Orthoversion predicts that Amasia will take form ~100 million years from now over the North Pole by closing the Caribbean and Artic oceans which are located in Pangea’s subduction girdle.