Calc-alkaline — and calc alkalic are equivalent terms applied to groups of igneous rocks that commonly occur together and that have compositions related by the characteristic chemical trends specified below. Understanding the genesis of these rocks is important … Wikipedia
Case hardening of rocks — Case hardening is a weathering phenomenon of rock surface induratoin. It is observed commonly in: felsic alkaline rocks, such as nepheline syenite, phonolite and trachyte; pyroclastic rocks, as pyroclastic flow deposit, fine air fall deposits and … Wikipedia
Superior 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… … Wikipedia
Litchfieldite — is a rare metamorphosed igneous rock. It is a variety of nepheline syenite and is composed of two near pure phases of feldspar, albite and microcline, with predominance of the first one, plus nepheline, sodalite, cancrinite and calcite. The mafic … Wikipedia
Nepheline syenite — of the Intrusive Complex of Tanguá, State of Rio de Janeiro, Brasil (Motoki et al., 2011a) Nephelene syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or… … Wikipedia
igneous rock — Any of various crystalline or glassy, noncrystalline rocks formed by the cooling and solidification of molten earth material (magma). Igneous rocks comprise one of the three principal classes of rocks, the others being metamorphic and sedimentary … Universalium
Phonolite — Aegirine phonolite. Dark prismatic minerals are aegirine phenocrysts. Phonolite is a rare igneous, volcanic (extrusive) rock of intermediate (between felsic and mafic) composition, with aphanitic to porphyritic texture. The name phonolite comes… … Wikipedia
geology — /jee ol euh jee/, n., pl. geologies. 1. the science that deals with the dynamics and physical history of the earth, the rocks of which it is composed, and the physical, chemical, and biological changes that the earth has undergone or is… … Universalium
Lamprophyre — Lamprophyres (Greek λαµπρός (lamprós) = bright and φύρω (phýro) = to mix) are uncommon, small volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks and small intrusions. They are alkaline silica… … Wikipedia
Paulingite — Infobox mineral name = Paulingite category = Zeolite Group boxwidth = boxbgcolor = imagesize = caption = formula = (K,Na,Ca)3 4(Si,Al)21O42 ·17 22H2O molweight = color = Colorless, light yellow, orange, red habit = typically as euhedral crystals… … Wikipedia
