The westward drift of the lithosphere. A tidal ratchet?
Is the westerly rotation of the lithosphere an ephemeral accidental recent phenomenon or is it a stable
process of Earth’s geodynamics? The reason why the tidal drag has been questioned as the mechanism
determining the lithospheric shift relative to the underlying mantle is the apparent too high viscosity of
the asthenosphere. However, plate boundaries asymmetries are a robust indication of the ‘westerly’
decoupling of the entire Earth’s outer lithospheric shell and new studies support lower viscosities in the