Giant Diamonds May Hold the Key To Superdeep Earthquakes (sciencemag.org) 11
"Earthquakes shouldn't occur more than 300 kilometers below Earth's surface, according to most geophysical models," reports Science magazine. "Yet they commonly do — a phenomenon that has mystified seismologists for decades."
Slashdot reader sciencehabit shares their report on one possible explanation: that water carried by the tectonic plates shoved beneath continents "could be triggering these deep temblors." The find may also explain another marvel: why a huge number of fist-size diamonds form at this depth...
Steven Shirey, a geochemist at the Carnegie Institution for Science...and his team took a closer look at how water might make its way down deep... Regardless of depth, Shirey and his team found that once rocks in the slabs reached temperatures above 580 degrees C, they were less able to hold water. As that water flooded out of the slab, it weakened the surrounding rocks and triggered quakes, Shirey and his colleagues report in AGU Advances. This water, typically chock-full of dissolved minerals, would also be available to fuel diamond formation...
"The temperature tells the story," says Douglas Wiens, a seismologist at Washington University in St. Louis who was not involved in the new study. If the tectonic slab starts out hot, as it would if the rocks are relatively young, he says, the plate will dehydrate at depths between 100 and 250 kilometers and thus won't carry water far enough down to generate deep quakes. But if rocks in the sinking slab are old and relatively cool, water will stay locked inside the sinking slab for a longer time, persisting there until it is released at depths of 300 to 500 kilometers or more.
Further work in both the lab and the field will be needed to fully understand the relationships between water released from sinking slabs and deep earthquakes, Wiens says. In the meantime, he says, it's clear that diamonds that form at those depths, imperfections and all, will be critical to teasing out the details of the story.
Slashdot reader sciencehabit shares their report on one possible explanation: that water carried by the tectonic plates shoved beneath continents "could be triggering these deep temblors." The find may also explain another marvel: why a huge number of fist-size diamonds form at this depth...
Steven Shirey, a geochemist at the Carnegie Institution for Science...and his team took a closer look at how water might make its way down deep... Regardless of depth, Shirey and his team found that once rocks in the slabs reached temperatures above 580 degrees C, they were less able to hold water. As that water flooded out of the slab, it weakened the surrounding rocks and triggered quakes, Shirey and his colleagues report in AGU Advances. This water, typically chock-full of dissolved minerals, would also be available to fuel diamond formation...
"The temperature tells the story," says Douglas Wiens, a seismologist at Washington University in St. Louis who was not involved in the new study. If the tectonic slab starts out hot, as it would if the rocks are relatively young, he says, the plate will dehydrate at depths between 100 and 250 kilometers and thus won't carry water far enough down to generate deep quakes. But if rocks in the sinking slab are old and relatively cool, water will stay locked inside the sinking slab for a longer time, persisting there until it is released at depths of 300 to 500 kilometers or more.
Further work in both the lab and the field will be needed to fully understand the relationships between water released from sinking slabs and deep earthquakes, Wiens says. In the meantime, he says, it's clear that diamonds that form at those depths, imperfections and all, will be critical to teasing out the details of the story.
i want one (Score:2)
Re: (Score:2)
You probably wouldn't be able to retire on one of those. They are rife with inclusions.
Re:i want one (Score:5, Informative)
Some are, some aren't. The famed Cullinan diamond, the largest ever found (over 3100 carats, 621.35 gm) was pretty much gem quality all through. Several of the largest gems cut from it ended up in the British Crown Jewels, Some of the cut gems (eg Cullinan II) have minor flaws, but more from less-than-perfect cutting, not inclusions.
https://en.wikipedia.org/wiki/... [wikipedia.org]
Re: (Score:2)
And those are exceedingly rare, which is why they're so valuable. Though I imagine that one could manufacture a similar stone if you wanted, and it wouldn't even cost all that much (the company doing it would still charge you an arm and a leg because . . .reasons).
Re: i want one (Score:3)
Re: (Score:2)
It's same old same old for that field of study (Score:2)
Read up on the history of the acceptance of tectonic plate theory or the interaction of physicist Thomas Gold geology.
The latter in particular is an example of what happens when a real science has a look at fields where the practitioners are mostly math/physics illiterate. Medicine (extension of biology) is another example as you point out.
Superdeep Earthquakes may hold (Score:2)
Many women ... (Score:2)