Zeolite facies describes the mineral assemblage resulting from the pressure and temperature conditions of low-grade metamorphism. Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i
The zeolite facies is generally considered to be transitional between diagenetic processes which turn sediments into sedimentary rocks, and prehnite-pumpellyite facies, which is a hallmark of subseafloor alteration of the oceanic crust around mid-ocean ridge spreading centres. In Geology and Oceanography, diagenesis is any chemical physical or biological change undergone by a Sediment after its initial deposition and during Sedimentary rock is one of the three main rock types (the others being igneous and Metamorphic rock) The prehnite-pumpellyite facies is a metamorphic facies typical of subseafloor alteration of the Oceanic crust around Mid-ocean ridge spreading centres Oceanic crust is the part of Earth's Lithosphere that surfaces in the Ocean basins A mid-ocean ridge or mid-oceanic ridge is an underwater Mountain range typically having a valley known as a Rift running along its axis formed by The zeolite and prehnite-pumpellyite facies are considered burial metamorphism as the processes of orogenic regional metamorphism are not required. Orogeny (Greek for "mountain generating" is the process of natural Mountain building and may be studied as a tectonic structural event as a geographical event and
Zeolite facies is most often experienced by pelitic sediments; rocks rich in aluminium, silica, potassium and sodium, but generally low in iron, magnesium and calcium. Zeolite facies metamorphism usually results in the production of low temperature clay minerals into higher temperature polymorphs such as kaolinite and vermiculite. Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and Kaolinite is a Clay mineral with the chemical composition Al 2 Si 2 O 5( OH)4 Vermiculite is a natural Mineral that expands with the application of Heat.
Mineral assemblages include kaolinite and montmorillonite with laumontite, wairakite, prehnite, calcite and chlorite. Montmorillonite is a very soft phyllosilicate mineral that typically forms in microscopic Crystals forming a clay. Laumontite is a Mineral, one of the Zeolite group Its molecular formula is (2 · 4 H2O, a hydrated calcium-aluminium Prehnite is a phyllosilicate of Calcium and Aluminium with the formula Ca2Al(AlSi3O10(OH2 Calcite is a carbonate mineral and the most stable polymorph of Calcium carbonate ( Ca[[carbon C]] O 3 This discusses some chlorine compounds Chlorite is also a type of mineral see Chlorite group. Phengite and adularia occur in potassium rich rocks. Phengite is a series name for dioctahedral Micas of composition K(AlMg2(OH2(SiAl4O10 similar to Muscovite but with addition Adularia is a tectosilicate mineral with formula K[[aluminum Al]] Si 3 O 8 Minerals in this series include zeolites, albite, and quartz. Zeolites (Greek zein, "to boil" lithos, "a stone" are hydrated Aluminosilicate Minerals and have a micro-porous structure Albite is a plagioclase Feldspar Mineral. It is the sodium endmember of the Plagioclase Solid solution series Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in
This occurs by dehydration of the clays during compaction, and heating due to blanketing of the sediments by continued deposition of sediments atop it. Zeolote facies is considered to start with temperatures of approximately 50 - 150 °C and some burial is required, usually 1 - 5 km.
Zeolite facies tends to correlate in clay-rich sediments with the onset of a bedding plane foliation, parallel with the bedding of the rocks, caused by alignment of platy clay minerals in a horizontal orientation which reduces their free energy state. Foliation is any penetrative planar fabric present in rocks. Foliation is common to rocks affected by regional metamorphic compression typical of orogenic
Generally plutonic and volcanic rocks are not affected overly much by zeolite facies metamorphism, although vesicular basalts and the like will have their vesicles flled with zeolite minerals, forming amygdaloidal texture. In Geology, an intrusion is a body of Igneous rock that has Crystallized from molten Magma below the surface of the Earth. Plate tectonics and hotspots Divergent plate boundaries At the Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. Zeolites (Greek zein, "to boil" lithos, "a stone" are hydrated Aluminosilicate Minerals and have a micro-porous structure Amygdules form when the vesicular cavities (created by expanding gas bubbles in Volcanic Lava) are filled with a secondary Mineral such as
See also
References
- Blatt, Harvey and Robert Tracy, 1995, Petrology: igneous, sedimentary, and metamorphic, Freeman, ISBN 0-7167-2438-3
| Metamorphic facies - edit |
|---|
| Prehnite-pumpellyite | Zeolite | Greenschist | Blueschist | Eclogite | Amphibolite | Granulite |
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic