Formation of Gneiss and Obsidian

Gneiss

Obsidian

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Formation

Mineral Content

Compound Content

Metamorphism

Types of Metamorphism

Weathering

Types of Weathering

Erosion

Types of Erosion

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.

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

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

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Impact Metamorphism

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Biological Weathering, Mechanical Weathering

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Chemical Erosion, Coastal Erosion, Sea Erosion

When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.

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

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Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

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Biological Weathering, Chemical Weathering, Mechanical Weathering

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Chemical Erosion, Coastal Erosion, Glacier Erosion

Gneiss and Obsidian Formation

Formation of rocks is a long process and hence, Gneiss and Obsidian formation sounds very interesting. According to the formation, all rocks are divided into :Igneous Rocks, Sedimentary 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 Gneiss and Obsidian, composition of Gneiss and Obsidian and their transformation.