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A distinctive new model for the initiation of Earth's plate tectonic network has been recently published in Nature Communications by an international team including Dr. Alexander Webb (HKU Division of Earth and Planetary Science & Laboratory for Space Research). It is increasingly accepted that a single-plate lithosphere preceded plate tectonics, and recent modeling suggests that this lithosphere was warming through time. In the new work, the team uses 3D spherical shell models to explore the consequences of this warming of the early single-plate lithosphere. They demonstrate that the warming would have led to thermal expansion, creating tensile stresses that generated a global network of rifts, dividing the lithosphere into tectonic plates within a span of roughly 5 million years.

This movie shows the growth of a global fracture network in response to thermal expansion, modeled as a radially outwards push at 0.03 km per million years (m.y.)), shown in a rotating reference frame. The colors represent stresses, which build up until they locally overcome the tensile strength of the lithosphere. In response, cracks form and spread, until they link up to form the global fracture network.   

For more information see the HKU press release: https://www.hku.hk/press/press-releases/detail/21307.html​

The open access paper can be downloaded here: https://www.nature.com/articles/s41467-020-17480-2