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Gabbro. Gabbro ( / ˈɡæb.roʊ /) is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth 's surface. Slow-cooling, coarse-grained gabbro is chemically equivalent to rapid-cooling, fine-grained basalt.
Gabbro is a village in Tuscany, central Italy, administratively a frazione of the comune of Rosignano Marittimo, province of Livorno. At the time of the 2011 census its population was 898. The village is about 12 km from Livorno and 10 km from Rosignano Marittimo. It gave its name to the type of rock known as gabbro. References
Diabase ( / ˈdaɪ.əˌbeɪs / ), also called dolerite ( / ˈdɒl.əˌraɪt /) 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 contain tachylite ...
Hornblende gabbro is an intrusive rock similar to normal gabbro (gabbro sensu stricto [1] ). In the QAPF classification it falls within the gabbro field, in which quartz makes up 0% to 5% of the QAPF mineral fraction, plagioclase makes up 90% or more of the total feldspar content, and the plagioclase is calcium-rich (% An > 50).
The Roosevelt Gabbros are an intrusive igneous geological formation in southwestern Oklahoma. They are one of two formations recognized in the Raggedy Mountain Gabbro Group, the other being the Glen Mountain Layered Complex. The Roosevelt Gabbros are generally characterized as biotite gabbros, which form many dikes and sills through the older ...
The Bushveld Igneous Complex ( BIC) is the largest layered igneous intrusion [1] [2] within the Earth's crust. [3] It has been tilted and eroded forming the outcrops around what appears to be the edge of a great geological basin: the Transvaal Basin. It is approximately two billion years old [4] and is divided into four limbs: northern, eastern ...
The Farmington Gabbro is postmetamorphic medium to coarse grained plutonic rock next to metagabbros. [2] The unit is surrounded by Proterozoic to early Paleozoic metamorphosed rock. [1] The major and trace elements of the pluton matches the composition of calc-alkaline basaltic magma. [2] The minerals present are plagioclase, hornblende ...
Pegmatite. A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than 1 cm (0.4 in) and sometimes greater than 1 meter (3 ft). Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite.