Formation of Banded iron formation and Hornfels

Banded iron formation

Hornfels

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1 Formation

1.1 Formation

The banded iron layers are formed in sea water when oxygen is released by photosynthetic cyano-bacteria. The oxygen then combines with dissolved iron in ocean to form insoluble iron oxides, which precipitated out, forming a thin layer of banded iron formation on ocean floor.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

1.2 Composition

1.2.1 Mineral Content

Hematite, Magnetite, Quartz

Andalusite

1.2.2 Compound Content

Fe, Iron(III) Oxide, Silicon Dioxide

Fe, Mg

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

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

Chemical Weathering

Biological 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

Coastal Erosion, Wind Erosion

Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Banded iron formation and Hornfels Formation

Formation of rocks is a long process and hence, Banded iron formation and Hornfels 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 Banded iron formation and Hornfels, composition of Banded iron formation and Hornfels and their transformation.