Formation of Nepheline Syenite and Gneiss

Nepheline Syenite

Gneiss

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1 Formation

1.1 Formation

Nepheline Syenites are formed due to alkaline igneous activities and are generally formed in thick continental crustal areas or in Cordilleran subduction zones.

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

Albite, Amphibole, Biotite, Cancrinite, Feldspar, Hornblende, Plagioclase, Pyroxene, Sodalite

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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1.3.2 Types of Metamorphism

Burial Metamorphism, Impact Metamorphism

Impact Metamorphism

1.3.3 Weathering

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1.3.4 Types of Weathering

Biological Weathering, Chemical Weathering

Biological Weathering, Mechanical Weathering

1.3.5 Erosion

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1.3.6 Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Nepheline Syenite and Gneiss Formation

Formation of rocks is a long process and hence, Nepheline Syenite 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 Nepheline Syenite and Gneiss, composition of Nepheline Syenite and Gneiss and their transformation.