How Is Greisen Formed?

Greisens are formed by endogenous alteration of granite during the cooling stages of emplacement. Greisen fluids are formed by granites as the last highly gas- and water-rich phases of complete crystallisation of granite melts.

What type of rock is Greisen?

Greisen, modification of granite, an intrusive igneous rock; it consists essentially of quartz and white mica (muscovite) and is characterized by the absence of feldspar and biotite.

What type of metamorphism is Greisen?

Greisen is a hydrothermally metamorphosed granitic rock. It is composed mostly of light-colored mica (muscovite, lepidolite, zinnwaldite) and quartz. ... It means that these rocks in most cases formed inside the granitic pluton itself that provided heat and hydrothermal fluids to initiate the greisenization.