Igneous Rocks Granite To Gabbro

Gabbro with large augite phenocrysts embedded in white plagioclase.

Igneous rocks granite to gabbro.

Granite is made from three commonplace minerals quartz mica and feldspar and when viewed from a distance appear tan pinkish or gray relying at the concentrations and grain sizes of the 3 minerals. Intrusive igneous rocks crystallize below earth s surface and the slow cooling that occurs there allows large crystals to form. Gabbro is a coarse grained and usually dark colored igneous rock it is an intrusive rock. Unlike granite gabbro is low in silica and has no quartz.

Slow cooling coarse grained gabbro is chemically equivalent to rapid cooling fine grained basalt much of the earth s oceanic crust is made of gabbro formed at mid ocean. It means that it formed as magma cooled slowly in the crust. Also gabbro has no alkali feldspar only plagioclase feldspar with a high calcium content. By the weathering of pre existing rocks.

Determines the color of the rock. Is caused by leaching. It is usually black or dark green in color and composed mainly of the minerals plagioclase and augite. The central cores of major mountain ranges consist of intrusive igneous rocks usually granite.

There are two basic types. Gabbro is a coarse grained dark colored intrusive igneous rock. Igneous rocks are formed from the solidification of molten rock material. When exposed by erosion these cores called batholiths may occupy huge areas of the earth s surface.

Gabbro has a variety of uses in the construction industry. Granite is a medium tocoarse grained acid igneous rock with essential quartz 20 and feldspar where alkali feldspar constitutes between 100 and 35 of the feldspars and minor mafic minerals. The texture of an igneous rock. Igneous rock is formed.

Trapped deep within the earth magma is authorized to cool slowly. When the magma solidifies within the earth s crust it cools slowly forming coarse textured rocks such as granite gabbro or diorite. It is the most abundant rock in the deep oceanic crust. Gabbro is a dark colored igneous rock that is considered to be the plutonic equivalent of basalt.

There is a gabbro intermediate or low silica content and rarely contains quartz. Records the rock s cooling history. Gabbro ˈ ɡ æ b r oʊ 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. Igneous rocks with similar composition are basalt extrusive equivalent of gabbro and diabase the same rock type could be named dolerite or microgabbro instead.

Examples of intrusive rocks are granite and gabbro. Is controlled by the composition of magma. Gabbro is a dark medium to coarse grained intrusive igneous rock composed of calcium plagioclase pyroxene and minor olivine but no quartz.