Submission+-Giant diamonds may hold the key to superdeep earthquakes (sciencemag.org)
sciencehabit writes: Earthquakes shouldn’t occur more than 300 kilometers below Earth’s surface, according to most geophysical models. Yet they commonly do—a phenomenon that has mystified seismologists for decades. Now, researchers suggest water carried by 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.
Once rocks in tectonic slabs reach temperatures above 580C, they are less able to hold water. As that water floods out of the slab, it weakens the surrounding rocks and triggers quakes, the team reports. This water, typically chock-full of dissolved minerals, would also be available to fuel diamond formation.
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. In the meantime, it’s clear that diamonds that form at those depths, imperfections and all, will be critical to teasing out the details of the story.
Once rocks in tectonic slabs reach temperatures above 580C, they are less able to hold water. As that water floods out of the slab, it weakens the surrounding rocks and triggers quakes, the team reports. This water, typically chock-full of dissolved minerals, would also be available to fuel diamond formation.
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. In the meantime, it’s clear that diamonds that form at those depths, imperfections and all, will be critical to teasing out the details of the story.
