bf59a24b-de3d-4ea9-a307-ce15e4d22d72 urn:uuid eng UTF-8 nonGeographicDataset nonGeographicDataset 2025-10-16T05:16:16 creation ISO 19115 2016 The mantle dynamical repertoire: plates, plumes, overturns and tectonic evolution bf59a24b-de3d-4ea9-a307-ce15e4d22d72 In the present mantle, plates and plumes are the main active components. However, calculations of the thermal evolution of the mantle based on purely thermal convection with plates and plumes yield very smooth changes, which are difficult to reconcile with the apparently episodic accumulation of continental crust and with observed changes in tectonic style through Earth history. The effects of composition on the density of the lithosphere, both at the surface and after subduction, can change the dynamics of plates and mantle convection, resulting in a repertoire of mantle behaviour that may better explain the observed tectonic evolution. Thus major mantle overturns may have occurred during the Archaean and possibly the Proterozoic, with dramatic tectonic and magmatic effects, and plate tectonics may not have worked in its modern form when the mantle was hotter. Plumes are not an alternative to plates: they come from a different thermal boundary layer. Plumes have probably played a significant but usually secondary role throughout Earth history. Earth Sciences GA Publication Journal Published_External Journal article (pdf) documentDigital Journal article (pdf) PDF Unnamed resource documentDigital HTML