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

I hope I'm not the only one.

[CaptainNerdCave]

Did anyone else read the headline and think, "Great, another ridiculous claim about the damage being wreaked by wireless network signals"?

Re:Funny typo

[MichaelSmith]

Words which start with "I" are the property of Apple Corp.

Flood basalts

[Ol Biscuitbarrel]

The author seems to imply that the Columbia River Basalts were generated by the mantle plume, a supposition that isn't in the paper's abstract. Far as I know the jury's still out there. Here's a pdf of a 2007 paper covering the same topic; or, if that won't open for you like it isn't for me at the moment, here's the Google Quick View version.

Re:Flood basalts

[khallow]

The author seems to imply that the Columbia River Basalts were generated by the mantle plume

That seems very reasonable given that at one point the two nearly coincide in position and time (cospatial and contempory) about 16-17 million years ago. Given this new information, I think we have a variety of reasonable guesses for how a hotspot can generate both a sequence of massive basalt floods and the lesser, but still substantial volcanic activity since. First, it is possible that most of the Columbia River basalts don't come from the hotspot itself, but instead come from melting of the fragment of plate that broke off, the lighter part of the melt may well have returned to the surface along the path cut by the hotspot's plume. Or the plate may have held back a significant amount of the plume, releasing a large bubble of magma at once.

Sure, the jury is still out, but we have an interesting model that may explain a number of mysteries of the western US such as the origin of the Columbia Plateau basalt floods, the basin and range development of the Nevada area, and the anomalous acceleration of the North American plate during this time.

Re:Great, just great.

[game kid]

You thought your life was going well, but you were just rearranging deck chairs on the Tectonic all along.

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