Inside Our Earth
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Three Layers of the Earth-Crust, Mantle and Core (outer core and Inner core).
Crust-Outermost or topmost layer of the earth is called crust.
Continental mass-Silica and Aluminium are the main mineral component of the continental mass. Continental mass is thus called Sial (Si =silica and al =aluminium or alumina)
Oceanic Crust-Silica and Magnesium are the main mineral components of the oceanic crust .Continental crust is therefore called Sima (Si=silica and ma=magnesium)
Mantle-The second layer of the earth
Core-Core is the innermost layer of the earth
The main mineral components of the core are nickel and Iron thus it is called Nife (Ni=nickel and Fe-ferrous(iron)).
Rocks and Minerals
A rock is a naturally occurring solid aggregate of mineral matter.
Rocks can be of different texture, colour and size.
There are mainly three types of rocks Igneous rocks, Sedimentary rocks and metamorphic rocks.
Latin word Ignis =fire.
Igneous rocks are of two types –Intrusive rocks and extrusive rocks
Intrusive rocks-When molten magma cools down beneath the earths crust it forms intrusive rocks. Intrusive rocks form from molten material (magma) that flows and solidifies underground.
Examples of intrusive rocks- Granite, Diorite.
Extrusive rocks-When the molten magma comes out of the earth’s surface and cools down it forms extrusive rocks.
Examples of extrusive rocks – Rhyolite, Andesite, Basalt etc
When the rocks break down into small pieces these ,small fragment are transported by wind,water .These compressed and hardened to form sedimentary rocks.
Examples of sedimentary rocks- Shale, Sandstone, Limestone, Conglomerate etc
Metamorphic rocks are any rock type that has been altered by heat, pressure, and/or the chemical action of fluids and gases.
Igneous and sedimentary rocks can be converted into metamorphic rocks under great heat , pressure and chemical reaction.
Example-limestone changes into marble.
Examples of Metamorphic rocks- Slate, Quartzite, Schist, marble.
Any type of rocks changes into another type under heat, pressure, chemical change and other conditions. This conversion of rocks from one type to another is called rock cycle.
Above process goes on and on several times, thus these process is called rock cycle.
Posted by Akash Pandey | Monday, 25 May 2015 | 4:54:00 pm