A deep geothermal well in California has tapped a very saline brine extraordinarily high in heavy metals and other rare elements; copper and silver are precipitated during brine production. Preliminary evidence suggests that the brine may be pure magmatic water and an active ore-forming solution. Metamorphism of relatively young rocks may also be occurring within accessible depths.
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Geothermal brine well: Mile-deep drill hole may tap ore-bearing magmatic water and rocks Undergoing Metamorphism