Granite

Granite - acidic intrusive igneous rock. It consists of quartz, plahyoklaza, potassium feldspar and mica - biotite and / or muscovite. Granites are widespread in continental crust. Efuzyvni analogues granite - ryolytы. The density of granite - 2600 kg / m ³, compression strength of 300 MPa.

Granites are playing a huge role in the structure of the crust of continents of the Earth. But unlike the igneous rocks of basic (gabbro, basalt, anorthosite, burrow holes, troktolyt) analogues are widespread on the moon and terrestrial planets, the existence of granite on the other planets of solar system is only indirect signs. So are indirect signs of the existence of granite on Venus. Among geologists is the expression "granite - the card of the Earth."

On the other hand, there are reasonable grounds to believe that the earth originated from the same substance as the other terrestrial planets. Primary structure of the Earth reconstructed as close of hondrytov. Since these species can vyplavlyatysya basalts, but not granite.

These facts led the first petrolohov to setting the origin of granites, the problems that attracted the attention of geologists for many years, but still far from complete solutions.

The author of one of the first hypotheses on the origin of granite was Bouэn N. - father of experimental petrology. Based on experiments and observations of natural objects he found that the crystallization of basaltic magma occurs in a number of laws. Minerals crystallize it in the following order (number Bouэna) that melt continuously enriched silicon, sodium, potassium and other fusible components. Therefore Bouэn suggested that the granites may appear recent dyfferentsyatamy basaltic melts.