Earths tectonic plates are weird as hell. First there werent any, then there was a massive shell, then there were babycontinents, then supercontinents, microcontinents, regular continents, all of them shifting around the Earths crust and changing its appearance, like a very slow inkblot test.
Now, it appears theyre set to get even stranger. A team of researchers led by the University of Houston has concluded that, beneath our worlds tectonic plates, theres another separate layer of independent plates doing their own thing.
Speaking at a joint conference between the Japanese and American Geophysical Unions in Tokyo this week, the team say that theyve been using seismic waves to peer beneath the crust. These waves travel at different speeds through different materials, and as such, researchers can use them to find out whats beneath their feet.
Their research uncovered a mysterious layer present beneath Japan, Korea, and Northeast China, as well as beneath the island of Tonga. Theyre definitely composed of the same material as modern tectonic plates, but theyre found incredibly deep within the mantle. So what are they?
The tectonic plates weve all come to know and love well, except creationists we suppose are found within the lithosphere, the outer shell of a rocky planet, including ours. They are composed of the crust whether thats the less dense continental variety or the dense, submarine oceanic flavor and the upper mantle, a layer of slowly moving, superheated solid rock called the asthenosphere.
This causes them to drift around, bang into each other, grind past each other, and sometimes even destroy each other. That, in essence, is where we were at as of 2017.
However, this new research suggeststhat beneath the seven/eight major tectonic plates resides another layer of them. They appear to be vast, continental-sized segments of ancient plates gliding fairly quickly around a transition zone 440-660 kilometers (about 273-410 miles) beneath the surface.
The base of the regular tectonic plates, at least when theyre flat on the surface, is about 200 kilometers. (124 miles), so the newly discovered ones are way beneath that. So whats going on here?
Its likely that these plates are ancient ones. They would have encountered another tectonic plate during their more shallow existence at a subduction zone. Being denser than the other, they would have sunk beneath their colossal opponent, broken off, and drifted down into the mantle.
The discovery of this new layer of plate tectonics solves a long-standing mystery.
On occasion, incredibly deep-seated earthquakes rock the countries sitting above these plates, but they appeared to be originating from way below any known tectonic plate. You need plates to get quakes, so this has baffling scientists for a while now.
However, this new research has shown that they are probably coming from this new layer of tectonic plates. They may be semi-detached from the primary plates these days, but these enormous slabs can still bend, buckle, and break and cause quakes as they do so. Indeed, their ongoing destruction is so energetic that its causing powerful shockwaves to make it all the way to the surface.
The research has yet to be peer-reviewed, but its looking likely that, once again, Earths hellish depths have been holding back more secrets from us than wed realized.[H/T: Guardian]