Geodynamic investigation of a Cretaceous superplume in the Pacific ocean

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The similarity in both age and geochemistry of the Ontong-Java, Hikurangi, and Manihiki plateaus suggests that they formed as a single superplateau from a unique mantle source. We investigate the necessity of a thermal superplume to form the Great Ontong-Java plateau at about 120 Ma using 3D spherical models of convection with imposed plate reconstruction models. The numerical simulations show that the giant plateau which formed as a result of melting due to the interaction of a plume head and the lithosphere would have been divided into smaller plateaus by spreading ridges, and end up at the present locations of Ontong-Java, Manihiki, and Hikurangi plateaus as well as a fragment in the western Caribbean. By comparing temperature and melt fraction between models with and without an initial thermal superplume, we propose that a Cretaceous superplume in Pacific at 120 Ma is required to form large igneous plateaus.

Physical Sciences, Geochemistry & Geophysics, Ontong-Java plateau, Hikurangi plateau, Manihiki plateau, Plate reconstructions, Mantle convection, Plumes, LARGE IGNEOUS PROVINCES, CORE-MANTLE BOUNDARY, ONTONG-JAVA, FLOOD BASALTS, DEPENDENT VISCOSITY, TOMOGRAPHY REVEALS, CLUSTER-ANALYSIS, PLATE MOTIONS, HOTSPOTS, MODELS, 0201 Astronomical and Space Sciences, 0402 Geochemistry, 0404 Geophysics, Geochemistry & Geophysics