Vermont SerpentiniteSerpentinite is a common rock on Earth, and probably throughout the solar system

Vermont SerpentiniteSerpentinite is a common rock on Earth, and probably throughout the solar system. It is a type of metamorphic rock, produced when one of the most common minerals in the planet – olivine – gets exposed to water near the surface of the Earth, which of course happens all the time. A bit of water and a bit of pressure and the mineral structure changes, turning it into a soft, easily deformed rock.Many serpentinites have a fibrous appearance like this one from Vermont. There can be two factors driving this appearance; first, these rocks are so soft that they can deform easily in response to the stresses of mountain building. In that case, these lines are slickenlines, reflecting one part of the rock grinding against another. Alternatively, some (But not all) serpentine minerals can grow in a habit where they form long needles; minerals that grow in this habit are lumped together as asbestos minerals. Serpentine-bearing rocks therefore can naturally host asbestos, and mines in the area where this rock came from in Vermont produced asbestos for more than half a century.Serpentinite rocks and serpentine minerals are most often found where little bits of Earth’s mantle get thrust up onto the continent, creating a feature we call an ophiolite. These are commonly produced when continents collide or when continents run into island arcs, as a bit of the mantle gets trapped in the collision zone. The serpentinites in Vermont are the remnant of the Taconic Orogeny, a mountain building event 440 million years ago where a volcanic island arc was thrust upon what is today New England, folding and faulting much of the area in the process.-JBBImage credit: James St. Johnhttps://flic.kr/p/2iE3pj4Referencehttps://bit.ly/2BhQPrkPrevious TES series on Asbestos and health problems:https://www.facebook.com/TheEarthStory/photos/a.352867368107647.80532.352857924775258/778584158869297 -- source link

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