Rhyolites And Granites

High silica rhyolites and granites 75 wt sio 2 anhydrous basis are common features of the crust as part of both the volcanic and the plutonic records while low crystallization pressure 250 mpa is typically inferred it has been suggested that they form via polybaric evolution with initial crystallization at relatively high pressures 500 mpa.

Rhyolites and granites. So if we assume the above to be true then the only difference between the rocks is that one is plutonic and the other is volcanic. Rhyolite is similar in composition and appearance to granite but it forms through a. Rhyolite extrusive igneous rock that is the volcanic equivalent of granite most rhyolites are porphyritic indicating that crystallization began prior to extrusion. However the abundances of critical trace.

Rhyolite is a silica rich igneous rock found throughout the world. Crystallization may sometimes have begun while the magma was deeply buried. Rhyolite is a fine grained igneous rock which is rich in silica. Rhyolite can be considered as the extrusive equivalent to the plutonic granite rock and consequently outcrops of rhyolite may bear a resemblance to granite.

The rock received its name from german geologist ferdinand von richthofen better known as the red baron a world war i flying ace the word rhyolite comes from the greek word rhýax a stream of lava with the suffix ite given to rocks. Granites and rhyolites appear to overlap in age although rhyolites built up first with the rhyolite pile thickening as later granites coarsened texturally to medium. One is intrusive and the other is extrusive. The trace element contents of granites and their volcanic equivalents rhyolites are highly variable more so than basalts largely because of the effect of small amounts of accessory phases such as zircon monazite allanite and titanite both in their source regions and during granite crystallization.

In such cases the rock may consist principally of well developed large single crystals phenocrysts at the time of extrusion. So i m going to make a general comment and say that a granite is genetically the same has the same composition as a rhyolite. Please don t take this as always true but it is a close enough estimate in most cases.