Oceanic Plateau Formation Implied by Ontong Java Plateau, Kerguelen Plateau and Shatsky Rise

Abstract

Oceanic plateaus are a significant type of large igneous provinces in the oceans, providing insights to regional tectonic events and mantle behavior. The three world’s largest oceanic plateaus, the Ontong Java Plateau, the Kerguelen Plateau and the Shatsky Rise, are representatives in displaying extraordinary fluxes of magma from mantle to lithosphere. Detailed description incorporating transdisciplinary observations on marine geology, geophysics and geochemistry allow us to test the two lively-debated oceanic plateau formation hypotheses (mantle plume and plate boundary models). Predictions from either hypothesis merely obtain partial support. It is therefore unclear to differentiate one model from another one regarding the oceanic plateau formation. Careful comparisons of the three oceanic plateaus show many commonalities and even more differences in their formation and evolution. This diversity signifies one may not be typical of all. Notably, several key common features, i.e ., massive and rapid eruption and near-ridge formation setting, imply that the lithospheric volcanic emplacement of oceanic plateaus was controlled by seafloor spreading despite a mantle plume exists peripherally. If a coincidence of mantle plume and spreading ridge occurs, it may indicate a plume-ridge interaction. One possible mechanism is that spreading ridge is dragged by a plume and migrates to the location of the plume. Another possibility is that the asthenosphere is fed by a plume nearby and generates melting anomalies along the spreading ridge.