plutoniche

Plutoniche is a term used in geology to refer to igneous rocks formed by the intrusion and crystallization of magma below the Earth’s surface. This plutonism contrasts with volcanic (extrusive) processes that produce rocks at or above the surface. Plutonitic rocks crystallize under relatively high pressure and slow cooling, which generally yields coarse-grained, easily visible crystals and a phaneritic texture.

The mineralogical composition of plutonic rocks spans the felsic to the mafic spectrum. Felsic plutonic rocks, such as granite and granodiorite, are rich in quartz and alkali feldspar, with light-colored minerals. Intermediate varieties include diorite and monzodiorite, while mafic counterparts include gabbro and diabase. Ultramafic plutons, which are rarer at shallow crustal levels, contain higher proportions of olivine and pyroxene. Textures can be granitic, hornblende-bearing, or pyroxene-bearing; pegmatitic textures feature exceptionally large crystals, and porphyritic textures show large crystals embedded in a finer matrix.

Plutonic rocks form extensive bodies known as plutons, which may take the form of batholiths, stocks, laccoliths, or smaller dikes and sills. They commonly crystallize at depths of several kilometers and are integrated into tectonic crust during assembly and metamorphic events. Radiometric dating of minerals such as zircon provides ages for crustal formation, while isotopic and trace-element studies help interpret tectonic settings, including crustal accretion, subduction, and collision processes.