Skarn

Skarn is rock formed when chemically active fluids from an igneous intrusion replace surrounding carbonate rock. It commonly contains new silicate minerals and may host metallic ores.

Contact metasomatism: Chemical replacement of rock by fluids, commonly near an igneous intrusion. Skarn forms through this fluid-driven replacement process at an intrusion’s contact.
Tungsten: A chemical element and metal with the highest melting point of any pure metal. Scheelite-bearing skarns are a major source of tungsten ore.
Limestone: A sedimentary rock composed chiefly of calcium carbonate, usually calcite. Limestone is a common carbonate protolith replaced during skarn formation.
Hornfels: A hard, fine-grained metamorphic rock formed mainly by heating near an igneous intrusion. Hornfels is chiefly heat-altered rock, whereas skarn records strong chemical replacement.
Bingham Canyon Mine: A large copper mine in Utah associated with a porphyry copper system. Its deposits include skarn zones formed where mineralizing fluids met carbonate rocks.
Metasomatism: Chemical alteration of rock through the addition or removal of substances by fluids. Skarn is a conspicuous product of metasomatic exchange between intrusion-derived fluids and carbonate rock.
Copper: A ductile metallic element that conducts heat and electricity exceptionally well. Copper skarns form important deposits where intrusive fluids transport and precipitate copper.
Dolostone: A sedimentary rock composed chiefly of the mineral dolomite. Dolostone supplies magnesium and calcium to many skarns as fluids alter it.
Marble: A metamorphic rock formed when limestone or dolostone recrystallizes. Marble can form from heat alone; skarn additionally records metasomatic chemical change.
Antamina Mine: A large polymetallic mine in Peru extracting copper, zinc, molybdenum, and silver. Antamina is a major example of a copper-zinc skarn deposit.

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