New Study Explains How Continents Leave Their Roots Behind

What is it about?

Archean continental lithosphere has been found beneath an upper layer of oceanic lithosphere along the margins of some ocean basins. We show with seismic data and numerical modeling that these lithospheric roots were detached along a mid lithosphere discontinuity (MLD), and left behind and emplaced beneath new oceanic lithosphere during opening of the Atlantic Ocean. Both the lithosphere-asthenosphere boundary and the MLD can serve as the boundary for accommodating lateral plate displacements.

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Why is it important?

This is the first-documentation of large-scale detachment of lower continental lithosphere from the upper parts, along the mid-lithosphere discontinuity, and its emplacement beneath younger ocean basins. It represents a major new element in the plate tectonic paradigm, in which all lateral plate displacements are considered to happen along the deeper, lithosphere-asthenosphere boundary. This new model explains many enigmatic observations of old lithosphere beneath young ocean basins.