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Gabbro is known in the construction industry by the trade name of black granite. [31] However, gabbro is hard and difficult to work, which limits its use. [32] The term "indigo gabbro" is used as a common name for a mineralogically complex rock type often found in mottled tones of black and lilac-grey.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
Examples of phaneritic igneous rocks are gabbro, diorite, and granite. Porphyritic textures develop when conditions during the cooling of magma change relatively quickly. The earlier formed minerals will have formed slowly and remain as large crystals, whereas, sudden cooling causes the rapid crystallization of the remainder of the melt into a ...
The cumulate rock is a plagioclase-pyroxene cumulate (a gabbro) and the melt is now more felsic and aluminous in composition (trending towards andesite compositions). In the above example, the plagioclase and pyroxene need not be pure end-member compositions (anorthite-enstatite), and thus the effect of depletion of elements can be complex.
The following is a list of rock types recognized by geologists.There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.
Diabase (/ ˈ d aɪ. ə ˌ b eɪ s /), also called dolerite (/ ˈ d ɒ l. ə ˌ r aɪ t /) or microgabbro, [1] is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grained to aphanitic chilled margins which may ...
The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic magma, which is high in magnesium and iron and produces basalt or gabbro, as it fractionally crystallizes to become a felsic magma, which is low in ...
Norite, also known as orthopyroxene gabbro, may be essentially indistinguishable from gabbro without thin section study under the petrographic microscope. The principal difference between norite and gabbro is the type of pyroxene of which it is composed.