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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.
Diorite was also used for stone vases by Bronze Age craftspeople, who developed considerable skill at polishing diorite and other stones. [38] The Egyptians had become skilled at shaping diorite and other hard stones by 4000 BCE. [39] A large diorite stela in the Louvre Museum dating to 1700 BCE is inscribed with the Code of Hammurabi. [40]
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 ...
Andesite is the extrusive equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs. The average composition of the continental crust is andesitic. [3] Along with basalts, andesites are a component of the Martian crust.
The name comes from two related rocks to which granodiorite is an intermediate: granite and diorite. The gran-root comes from the Latin grānum for "grain", an English language derivative. Diorite is named after the contrasting colors of the rock.
Dacite from the Lassen Volcano National Park. Dacite (/ ˈ d eɪ s aɪ t /) is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides.
Nepheline-bearing diorite is an intrusive rock with a composition intermediate between diorite and nepheline diorite.It is defined in the QAPF classification as coarse-grained igneous rock in which feldspathoids makes up 0% to 10% of the QAPF mineral fraction and are predominantly nepheline; plagioclase makes up 90% or more of the total feldspar content; and the plagioclase is sodium-rich (%An ...
For example, Coastal Batholith of Peru consists of 7–16% gabbro and diorite, 48–60% tonalite (including trondhjemite), and 20–30% granodiorite, with 1–4% granite. [22] These TTG rocks in continental arc batholiths may partially originate from the magma differentiation (i.e. fractional crystallisation ) of the subduction induced mantle ...