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However, gabbro is an essential part of the oceanic crust, and can be found in many ophiolite complexes as layered gabbro underling sheeted dike complexes and overlying ultramafic rock derived from the Earth's mantle. These layered gabbros may have formed from relatively small but long-lived magma chambers underlying mid-ocean ridges. [24]
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 ...
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.
Basalt. A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron.Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite.
The Mocksville complex consist mostly of metagabbro, but there are outcrops where you can see the contact between the metagabbro rocks and the gabbro (Farmington). [1] The contact could be easily seen because the Farmington Gabbro is the only non- metamorphosed rock unit in this area of plutons so distinguishing between a metagabbro and gabbro ...
Anorthosite on Earth can be divided into five types: [3] Archean anorthosites; Proterozoic anorthosite (also known as massif or massif-type anorthosite) – the most abundant type of anorthosite on Earth [2] Layers within Layered Intrusions (e.g., Bushveld and Stillwater intrusions) Mid-ocean ridge and transform fault anorthosites
Quartz gabbro is an intrusive rock with a composition intermediate between gabbro and tonalite.It is defined in the QAPF classification as coarse-grained igneous rock in which quartz makes up 5% to 20% of the QAPF mineral fraction, plagioclase makes up 90% or more of the total feldspar content, and the plagioclase is calcium-rich (%An > 50).
QAPF diagram for classification of plutonic rocks. A QAPF diagram is a doubled-triangle plot diagram used to classify intrusive igneous rocks based on their mineralogy.The acronym QAPF stands for "Quartz, Alkali feldspar, Plagioclase, Feldspathoid (Foid)", which are the four mineral groups used for classification in a QAPF diagram.