Basal mantle structure regenerated through supercontinents
摘要
The African large low shearwave-velocity province (LLSVP) advected plumes manifest as large igneous provinces (LIPs) during Pangea breakup. The existence of such basal mantle structures during earlier supercontinents is unknown. Here we analyze samples from China and Brazil to demonstrate with literature data a series of seven LIPs of supercontinent Rodinia from 940–720 million years ago. Multi-proxy reconstruction results in a coherent ring of LIPs comparable with the size of Rodinia that resembles the product of an ancient LLSVP whose edges advected LIP-producing plumes. Oceanic lithosphere recycling following supercontinental assembly is evident in Nd isotopes as evolving LIP-sources. There is a same secular variational pattern of LIP sources with a replenished depleted component advected by plumes as well as a similar manner yet contrasting paleogeographic configurations corresponding to supercontinental breakup between Rodinian and Pangean LLSVPs. This evolving pattern of LLSVPs suggests their partial regeneration (replenishment and migration) between supercontinents.