Formation of Trachyandesite and Gneiss

Trachyandesite

Gneiss

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1 Formation

1.1 Formation

Trachyandesite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Gneiss is a high grade metamorphic rock i.e. it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of Gneiss forms from volcanic rock, shale or granitie.

1.2 Composition

1.2.1 Mineral Content

Alkali feldspar, Biotite, Olivine, Plagioclase, Pyroxene, Sodic plagioclase

Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon

1.2.2 Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

1.3 Transformation

1.3.1 Metamorphism

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97% Igneous Rocks Rocks have it !

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50% Metamorphic Rocks Rocks have it !

1.3.2 Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism

Impact Metamorphism

1.3.3 Weathering

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99% Igneous Rocks Rocks have it !

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65% Metamorphic Rocks Rocks have it !

1.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Mechanical Weathering

1.3.5 Erosion

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92% Igneous Rocks Rocks have it !

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77% Metamorphic Rocks Rocks have it !

1.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Trachyandesite and Gneiss Formation

Formation of rocks is a long process and hence, Trachyandesite and Gneiss formation sounds very interesting. According to the formation, all rocks are divided into :Igneous Rocks, Fossil Rocks and Metamorphic Rocks. Igneous rocks form by crystallization of magma or lava. The magma is made up of various components of pre-existing rocks which have been subjected to melting either at subduction zones or within the Earth's mantle. Igneous rocks are generally seen at mid ocean ridges or in intra-plate hotspots. Sedimentary rocks are formed when sediments accumulate gradually. As the sediments are buried they get compacted as more and more material is deposited on top. Eventually the sediments become so dense that they form a rock. Metamorphic rocks are rocks which once existed as igneous or sedimentary rocks but have been subjected to varying degrees of pressure and heat within the Earth's crust. Get to know all about formation of Trachyandesite and Gneiss, composition of Trachyandesite and Gneiss and their transformation.