Troctolite is a rare ultramafic intrusive rock type. Ultramafic (also referred to as ultrabasic) rocks are igneous and meta -igneous rocks with very low Silica content (less than 45% generally In Geology, an intrusion is a body of Igneous rock that has Crystallized from molten Magma below the surface of the Earth. It consists essentially of variable amounts of olivine and calcic plagioclase along with variable minor pyroxene. The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Plagioclase is a very important series of tectosilicate Minerals within the Feldspar family The pyroxenes are a group of important rock-forming Silicate minerals found in many Igneous and metamorphic rocks. It thus is midway between peridotite and anorthosite. A peridotite is a dense coarse-grained Igneous rock, consisting mostly of the minerals Olivine and Pyroxene. Anorthosite (æˈnɔrθəsaɪt/ /ə- is a Phaneritic, Intrusive Igneous rock characterized by a predominance of Plagioclase Feldspar 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. Ultramafic to mafic layered intrusions are found in typically ancient Cratons and are rare but worldwide in distribution The Windimurra Intrusion is a giant ultramafic-mafic intrusion emplaced within the Yilgarn craton of Western Australia. Western Australia is a state occupying the entire western third of the Australian continent. Voisey's Bay is a Canadian Bay in the province of Newfoundland and Labrador. Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Cobalt (ˈkoʊbɒlt is a hard lustrous silver-grey Metal, a Chemical element with symbol Co. The term sulfide ( sulphide in British English) refers to several types of Chemical compounds containing Sulfur in its lowest Oxidation Modern Labrador Just like its island neighbour Newfoundland early settlement in Labrador was tied to the sea as demonstrated by the Montagnais, Innu and The Stillwater igneous complex is a large ultramafic to mafic layered intrusion located in southern Montana in Stillwater, Sweet Grass and Montana ( is a state in the Western United States. One-third of the state in the western part contains numerous mountain ranges (approximately 77 named of the northern The chuprichondira geological time interval covers roughly the time span between the demise of the non- avian Dinosaurs and beginning of the most recent Ice Age, approximately Rùm (rˠuːm a Scottish Gaelic name often Anglicised to Rum) is one of the Small Isles of the Inner Hebrides, in the district of Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. Troctolite is also found in the Merensky Reef of the Bushveld Igneous Complex, South Africa. The Merensky Reef, is a layer of Igneous rock in the Bushveld Igneous Complex (BIC in the Transvaal which together with an underlying layer the Upper The Bushveld Igneous Complex (or BIC) is a large Igneous Intrusion within the Earth's crust which has been tilted and eroded and now The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa

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

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