ultramafic rock
51Komatiite — Komatiites are ultramafic mantle derived volcanic rocks. They have low SiO2, low K2O, low Al2O3, and high to extremely high MgO. They were named for their type locality along the Komati River in South Africa. True komatiites are very rare and… …
52Superior craton — in the west. The western margin extends from northern Minnesota through eastern Manitoba to northwestern Ontario.The formation of the Superior craton is best explained within the context of 2.72 2.68 Ga accretion of small continental plates and… …
53Anorthosite — (pronEng|æˈnɔrθəsaɪt/, /ə ) is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90–100%), and a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most… …
54Peridotite — A peridotite is a dense, coarse grained igneous rock, consisting mostly of the minerals olivine and pyroxene. Peridotite is ultramafic and ultrabasic, as the rock contains less than 45% silica. It is high in magnesium, reflecting the high… …
55Tuff — (from the Italian tufo ) is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff should not be confused with tufa , another type of rock. Volcanic ashThe products of a volcanic eruption are… …
56Phlogopite — Phlogopite, Monte Somma, Italy General Category Mica, phyllosilicates …
57Anthophyllite — Infobox mineral name = Anthophyllite category = boxwidth = boxbgcolor = caption = formula = Hydrous Magnesium Iron silicate (Mg,Fe)7Si8O22(OH)2 molweight = color = gray to green, brown, and beige habit = Rarely as distinct crystals. Commonly… …
58olivine — olivinic /ol euh vin ik/, olivinitic /ol euh vi nit ik/, adj. /ol euh veen , ol euh veen /, n. Mineral. any of a group of magnesium iron silicates, (Mg,Fe)2SiO4, occurring in olive green to gray green masses as an important constituent of basic… …
59pyroxene — pyroxenic /puy rok sen ik/, adj. /puy rok seen, peuh , puy rok seen /, n. any of a very common group of minerals of many varieties, silicates of magnesium, iron, calcium, and other elements, occurring as important constituents of many kinds of… …
60Narryer Gneiss Terrane — Stratigraphic range: > 3.3 Ga Satellite image of Jack Hills in the Narryer Gneiss Terrane Type Geological complex Sub units …
