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Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of 150 °C (300 °F), and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. [1]
Metasomatism (from the Greek μετά metá "change" and σῶμα sôma "body") is the chemical alteration of a rock by hydrothermal and other fluids. [1] It is traditionally defined as metamorphism which involves a change in the chemical composition, excluding volatile components. [2]
An active fluid is a densely packed soft material whose constituent elements can directly inject and dissipate energy. [ 1 ] [ 2 ] [ 3 ] Examples include dense suspensions of bacteria , microtubule networks or artificial swimmers. [ 1 ]
The metamorphic rock exposed in orogenic belts may have been metamorphosed simply by being at great depths below the Earth's surface, subjected to high temperatures and the great pressure caused by the immense weight of the rock layers above. This kind of regional metamorphism is known as burial metamorphism.
This contact metamorphism results in a rock that is altered and re-crystallized by the extreme heat of the magma and/or by the addition of fluids from the magma that add chemicals to the surrounding rock (metasomatism). Any pre-existing type of rock can be modified by the processes of metamorphism. [4] [5]
Mixing between ascending hot mineral-bearing fluids and the cold descending water. Cooling of the ascending high-temperature solution. VMS deposits form in zones of extension and active volcanism. The original fluid is mainly cold, alkaline, deficient-in-metals sea water and in some cases it can include a lesser proportion of magmatic fluid.
An intrusion of magma that heats the surrounding rock causes contact metamorphism—a temperature-dominated transformation. Pressure metamorphism occurs when sediments are buried deep under the ground; pressure is dominant, and temperature plays a smaller role. This is termed burial metamorphism, and it can result in rocks such as jade. Where ...
In inorganic chemistry, mineral hydration is a reaction which adds water to the crystal structure of a mineral, usually creating a new mineral, commonly called a hydrate.. In geological terms, the process of mineral hydration is known as retrograde alteration and is a process occurring in retrograde metamorphism.