Lava lamp tectonics: Research suggests giant blobs of subducted sediment float up through deep Earth

Sand and mud subducted off the coast of California around 75 million years ago returned to the Earth's crust by rising up through the mantle as enormous diapirs, like blobs in a lava lamp, new research shows.

source https://www.sciencedaily.com/releases/2021/08/210804123559.htm