Thursday, 2 July 2015

Internal structure of Earth

Internal structure of Earth
The Geology of Earth is complex so that why the internal structure is divided into three parts
1)      Crust   2)  Mantle  3) Core
It is easy to study and understand the internal structure of Earth by this division. Geologist can easily identify and study the nature of rock and minerals.

1)      The Crust: - It is the upper most part of Earth; it is solidified and hard which composes of different rocks. The Earth crust is divided into two part
i)   Continental Crust              ii) Oceanic Crust
i)  Continental Crust: - Continental Crust is the continental shelf or part of earth and under the mountains. Continental Crust is lesser denser and mostly light rocks are formed. Continental Crust is rich in Si and Al and termed as SIAL Crust. Continental Crust thickness ranges from 30 to 100km. Specific gravity of Continental Crust is 2.7 to 2.9.
ii)    Oceanic Crust:- Oceanic Crust is too much denser then Continental Crust. Oceanic Crust is dark in color. Oceanic Crust is composed of Si and Mg it is term as SIMA.  Specific gravity of Oceanic Crust is 3.5 to 4.1. Dark and heavy minerals are found in Oceanic Crust.
    The line or separation between Crust and Mantle is known as Mohorovicich Discontinuity.
2)       Mantle:- It is semi-molten form, all the rocks are in molten form. 84% of Earth’s volume is made up of mantle. 2,886(1,793 mil) average thickness of mantle.
Geologist always go for a easy way to understand the Geology so for that purpose Mantle is divided into further more part
i)        Upper mantle                    ii) Lower mantle
i)  Upper mantle: - Upper mantle is semi-molten material; Upper mantle is composed of Si and Mg minerals.
ii)  Lower Mantle: - Lower Mantle has hot molten material; Lower Mantle is Si and Mg rich minerals. The Lower Mantle has too much temperature then upper mantle.
After the Lower mantle Gutenberg Discontinuity starts which separates mantle from core.
3)      The Core: - Core is the most inner part of Earth, The Core is thicker then crust and Mantle. The Core show real composition of Earth. The Core is mostly rich in Fe and Ni, same as a meteorites tells us that all the solar system is derived from one and same body.
To understand the mystery of core Geologist had divided the Core into two parts
i)   Outer Core            ii)  Inner Core
i)  Outer Core: - Outer Core is totally in molten form, Outer Core is composed of SIMA as well as little bit S, Ni and Fe in small content. Due to high pressure this portion behaves like solid but it is in melt form.
ii) Inner Core : - Inner Core is also in molten , Inner Core the portion where too much heat and pressure. Due to high pressure it totally behaves like solid material. Ni and Fe are the main of which Inner Core is compose of.
Lithosphere: - Crust and Upper makes up the Lithosphere. It is the hard portion of Earth mostly rocks are formed and found.
Asthenosphere: - It is highly viscous material and ductile in nature. Lithosphere lies above the Asthenosphere.


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