HI - MSU Researchers Discover 'Missing' Piece of Hawaii's Formation

An oceanic plateau has been observed for the first time in the Earth’s lower mantle, 800 kilometers deep underneath Eastern Siberia, pushing Hawaii’s birthplace back to 100 million years, says a Michigan State University geophysicist.

The discovery came when Songqiao “Shawn” Wei, an Endowed Assistant Professor of Geological Sciences in MSU’s Department of Earth and Environmental Sciences, noticed something unusual in his data using groundbreaking techniques. Wei’s research will be published on Nov. 20 in the journal Science.

The Earth’s mantle is mostly solid, but at a mid-ocean ridge it melts creating new oceanic crust between two tectonic plates such as the Pacific Plate. Typically, this new Pacific Ocean crust has a uniform thickness of four miles, Wei said.

As the plates continue to move, a hot plume of solid rocks slowly rises in the mantle melting the tectonic plate to create volcanoes like the Hawaiian Islands. The mantle plume has a mushroom-like shape with a wide head that is thousands of miles across and a thin tail that is only of a few hundred miles across.  

Wei said once this mushroom head reaches the Earth’s surface in the ocean, it stretches and flattens out, while it melts the overriding tectonic plate to form a pancake-shaped 20-mile-thick oceanic plateau. This process continues as more of the mantle reaches the surface and the overriding plate continues to move. Over time, what remains is a dotted trail of islands.

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