How do introversion, extroversion, and orthoversion models explain the supercontinent cycle?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Watch Earth's Continents Move — paleogeography Watch a time-lapse of Earth changing through geologic time, from the Cambrian Era to the projected period of Pangea Proxima.

The supercontinent cycle describes the periodic process of supercontinent formation, breakup, and reconsolidation. While the cycle is primarily driven by mantle convection, three specific models explain how subduction zones dictate the movement of continental fragments:

Introversion: After a supercontinent rifts and an interior ocean forms, subduction zones develop within that new ocean. These zones consume the oceanic crust, drawing the fragments back together to form a new supercontinent in a novel configuration.
Extroversion: Continental fragments drift apart as an interior ocean expands. They eventually collide on the opposite side of the globe, causing the former exterior ocean to contract and vanish as the new supercontinent coalesces.
Orthoversion: Fragments are trapped within a north-south band of subduction located beyond the margins of the previous supercontinent. The fragments drift and collide within this band, forming the next supercontinent approximately 90° (one-quarter of the globe) away from the center of the former landmass.

These models illustrate how the spatial arrangement of subduction zones determines the geographic path of future continental drift.1