Blue Arrow
Blueschist on a base of radiolarian chert, both from Curry County. Both of these rocks are unusual, but are commonly found together in rocks formed in subduction zones, where an oceanic tectonic plate has collided with a continental plate. The blueschist is formed when the basalt that makes up the ocean floor is rapidly dragged to tremendous depths during the collision, then rapidly pushed back to the surface, causing rare minerals including blue glaucophane, green omphacite and red garnets to form. This piece also includes large grains of iron pyrite. The chert formed in the deepest part of the ocean floor, where crystalline quartz skeletons of dead radiolarians, a form of plankton, accumulated and fused together to make a dense, tough rock.
HxWxD:8"x7"x6"
300-150 million years old
Available for sale: $275
HxWxD:8"x7"x6"
300-150 million years old
Available for sale: $275
