Yellowstone Hot Spot Shreds Ancient Pacific Ocean

jamie passes along this excerpt from DiscoveryNews: "If you thought the geysers and overblown threat of a supervolcanic eruption in Yellowstone National Park were dramatic, you ain't seen nothing: deep beneath Earth's surface, the hot spot that feeds the park has torn an entire tectonic plate in half. The revelation comes from a new study (abstract) in the journal Geophysical Research Letters that peered into the mantle beneath the Pacific Northwest to see what happens when ancient ocean crust from the Pacific Ocean runs headlong into a churning plume of ultra-hot mantle material."

Comments

Very cool, but article exaggerates to sound cooler

[penguinchris]

If you look at the illustration in the article (and I assume in the original paper, I have access but have to login to a vpn and so on, I will see later since I'm interested), it's quite clear what happened and it's really not what you might think when you hear it "shredded" a tectonic plate. I think what's being implied is that it shredded the plate at the surface, but it happened far underground, in the mantle.

As the subducting plate subducts, it goes down into the mantle and in this case the mantle plume weakened it (by getting into fractures or whatever) and broke it off. So the slab disappears down into the mantle eventually (though these can stick around for years, detached). It's very interesting, but the same thing often happens without being cut off by a mantle plume. It's more or less a guaranteed result in a subduction zone, because the subducting slab isn't strong enough to support its own weight pulling on it after a certain point. Makes absolute sense if you look at a diagram of how subduction works.

Subducting slabs can also be cut off by things like strike-slip faults, which IIRC happened in northern California as a result of the San Andreas (don't quote me on that though). You can see the slabs in the mantle by various imaging techniques.

IAAGGS