Formation of Shale and Gneiss

Shale

Gneiss

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1 Formation

1.1 Formation

Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.

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, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides

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

1.2.2 Compound Content

Ca, Fe, Mg, Silicon Dioxide, Sodium

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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19% Sedimentary Rocks Rocks have it !

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50% Metamorphic Rocks Rocks have it !

1.3.2 Types of Metamorphism

Not Applicable

Impact Metamorphism

1.3.3 Weathering

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78% Sedimentary 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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86% Sedimentary Rocks Rocks have it !

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77% Metamorphic Rocks Rocks have it !

1.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Shale and Gneiss Formation

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