What is the classification of pegmatite?
Pegmatites are classified as LCT and are subdivided into 4 unique groups to the Pegmatite belt. Structural analysis shows an exclusive post-orogenic timing of pegmatite emplacement. Sn, Ta and Nb element enrichment was due to pegmatite fractionation and not contamination as previously thought.
What are granitic pegmatites?
A pegmatite is a holocrystalline intrusive igneous rock composed of interlocking phaneritic crystals usually larger than 2.5cm in size.
What are zoned pegmatites?
Zoned pegmatites are primary in nature, having formed from the crystallization of the pegmatitic melt. On the whole, they appear to have formed from the outside walls inward … are alkali feldspar, sodic plagioclase, quartz and minor muscovite or biotite.
Is granite pegmatite intrusive or extrusive?
Examples of intrusive igneous rocks are diorite, gabbro, granite, pegmatite and peridotite. Extrusive igneous rocks erupt onto the surface, where they cool quickly to formsmall crystals.
What is the characteristics of pegmatite?
Pegmatites contain exceptionally large crystals and they contain rarely minerals than other types of rocks. They have interlocking crystals usually larger than 2.5 cm in size. Generally most Pegmatites are found in sheets of rock that are dikes and veins Also near large masses of igneous rocks called batholiths.
Where is granite pegmatite found?
Occurrence. Notable pegmatite occurrences are found worldwide within the major cratons, and within greenschist-facies metamorphic belts. However, pegmatite localities are only well recorded when economic mineralisation is found.
Is pegmatite a type of granite?
Etymology. The word pegmatite derives from Homeric Greek, πήγνυμι (pēgnymi), which means “to bind together”, in reference to the intertwined crystals of quartz and feldspar in the texture known as graphic granite. The term was first used by René Just Haüy in 1822 as a synonym for graphic granite.
How does granite pegmatite form?
Pegmatites form from waters that separate from a magma in the late stages of crystallization; this activity often occurs in small pockets along the margins of a batholith. Pegmatite can also form in fractures that develop on the margins of the batholith. This is how pegmatite dikes are formed.
How is granite pegmatite formed?
Pegmatites form from waters that separate from a magma in the late stages of crystallization; this activity often occurs in small pockets along the margins of a batholith. Pegmatite can also form in fractures that develop on the margins of the batholith. This is how “pegmatite dikes” are formed.
Is pegmatite basaltic or granitic?
Most pegmatites have a simple composition, often being composed entirely of minerals common in granite, such as feldspar, mica, and quartz.