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 is Greisen in geology?
Greisen is a highly altered granitic rock or pegmatite. Greisen is formed by self-generated alteration of a granite and is a class of moderate- to high-temperature magmatic alteration related to release of volatiles dissolved in a magma during the solidification of that magma.
What is Kaolinization?
Kaolinization. Kaolinization refers to the alteration of alkali feldspar into the clay mineral kaolinite in the presence of slightly acidic solutions. Rain readily dissolves carbon dioxide (CO2) from the atmosphere, promoting weathering of granitic rocks.
What is Greisen deposit?
Greisen deposits consist of disseminated cassiterite and cassiterite-bearing veinlets, stockworks, lenses, pipes, and breccia (fig. 3) in gangue composed of quartz, mica, fluorite, and topaz.
How is skarn formed?
A skarn is formed by a variety of metasomatic processes during metamorphism between two adjacent lithologic units. Skarn can form in almost any lithology type such as shale, granite and basalt but the majority of skarns are found in lithology containing a limestone or a dolomite.
How is jarosite formed?
For the in-situ experiments, jarosite was formed by co-precipitation from a solution of iron and potassium sulphates at a range of temperatures and compositions to represent a variety of environments and scenarios.
What is silicification in geology?
—Silicification is the replacement of original skeletal material accomplished through the concurrent dissolution of calcium carbonate and precipitation of silica. The processes is aided by the nucleation of silica to organic matter which surrounds the mineral crystallites within the shell.
What is the process of Serpentinization?
Definition. Serpentinization is the process of hydrothermal alteration that transforms Fe-Mg-silicates such as olivine, pyroxene, or amphiboles contained in ultramafic rocks into serpentine minerals. Much of the uppermost mantle in oceanic setting is so altered, as are the cumulus parts of layered intrusions.
What is the meaning of skarn?
[ skärn ] A coarse-grained metamorphic rock formed by the contact metamorphism of carbonate rocks. Skarn typically contains garnet, pyroxene, epidote, and wollastonite.
Where is jarosite mineral found?
Antarctica
Jarosite has been found in the ice cores that were extracted from Antarctica by a team of international researchers recently.
What is jarosite precipitation?
Abstract: Jarosite precipitation process (JPP) is the most frequently used procedure for iron removal in the hydrometallurgical zinc extraction process. However, there is a gap in the knowledge of the relationship between operational parameters and the low contaminant JPP on the industrial scale.
What causes silicification?
Silicification happens when rocks or organic materials are in contact with silica-rich surface water, buried under sediments and susceptible to groundwater flow, or buried under volcanic ashes. Silicification is often associated with hydrothermal processes.