Troctolite

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Troctolite is a rare ultramafic intrusive rock type. It consists essentially of variable amounts of olivine and calcic plagioclase along with variable minor pyroxene. It thus is midway between peridotite and anorthosite. Troctolite is found in some Ultramafic to mafic layered intrusions such as in the Archean Windimurra intrusion of West Australia, the Voisey's Bay nickel-copper-cobalt magmatic sulfide deposit of northern Labrador, the Stillwater igneous complex of Montana and the Tertiary Rhum layered intrusion of the island of Rùm, Scotland. Troctolite is also found in the Merensky Reef of the Bushveld Igneous Complex, South Africa.

[edit] References

• Troctolite (allivalite): Isle of Rhum, northwestern Scotland Accessed Jan. 5. 2006
• Geology of the Voisey's Bay Deposits abstract Accessed Jan. 5. 2006
• Blatt, Harvey and Robert J. Tracy, 1996, Petrology: Igneous, Sedimentary and Metamorphic, 2nd ed., p. 72, Freeman, ISBN 0-7167-2438-3