Alteration Types In Granitic Rocks

Present study aims to understand the nature of.

Alteration types in granitic rocks. These areas were differentiated in. Mineral alteration refers to the various natural processes that alter a mineral s chemical composition or crystallography. Phyllic alteration is associated with porphyry cu deposits but also with mesothermal precious metal ores and volcanogenic massive sulfide deposits in felsic rocks. And zoning of hydrothermally altered rock the age and type of mineralization and hydrothermal alteration and trends or patterns of veins and faults.

Mineral alteration is essentially governed by the laws of thermodynamics related to energy conservation relevant to environmental conditions often in presence of catalysts the most common and influential being water h 2 o. The chemical and textural characterization of various types of plagioclase alterations allows elucidation of the granitic hydrothermal systems. About 10 types are being named as under though numerous permutations and combinations often tend to produce mixed variables. Hydrothermal alteration and related solid and aqueous phase geochemical signatures by dana j.

Bradley dalton winfield g. They have two different origins. It corresponds to the outcropping of the lower part of the fractured horizon of an alteration profile. Purulia district of west bengal is geologically dominated mostly by proterozic hard granite gneiss rocks including soft phyllite and mica schist of singhbhum group as part of chotanagpur plateau.

This alteration grades into the potassic type by increasing amounts of k ak k feldspar and or biotite and into the argillic type by increasing amounts of h ah clay minerals. Types of wall rock alteration now coming to the exact question raised the types are varied and manifold. Alteration is defined as any alteration of rocks or minerals by the reaction of hydrothermal fluid with preexisting solid phases. Hydrothermal alteration can be isochemical like meta morphism and dominated by mineralogical changes or it can be metasomatic and result in significant addition or removal of elements.