Compostion of the Earth's Crust and lithosphere

                       

              The Earth Crust.

    Composition of the Earth Crust.

      The Earth’s-Crust is the thin and outermost layer of our Planet, It is composed of various rocks and minerals.
The most abundant elements that are found in the Earth's Crust are:- Aluminum, Iron, Calcium, Potassium, Magnesium, Oxygen, and Silicon, etc. when these elements react with each other to form Crystalline Compounds they are called Minerals.

·       The Boundary which separates the crust from the molten Mantle is called Moho (Mohorovicic) Discontinuity, (it is named after the Croatian scientist who discovered it). 
·     Earth’s crust consists of The Continents and the Ocean Basins; the continental part of Earth's crust is called the Continental Crust and its Oceanic Part is Called Oceanic Crust.
·      The thickness of Earth’s Crust varies from about 07 to 40 km (about 04 to 25 miles).

       Types of Earth Crust

    a) Continental Crust.

·     Continental crust occupies one-fourth (29%) of the earth's surface. It comprises two zones: The lower zone which is composed of  Dense Mafic Rock and the  Upper Zone is comprised of  Felsic Rock.
·     The Continental crust is thicker than the Oceanic Crust. its average thickness is about 35 km (22 miles).

      Its thickness varies from 20 km (12.5 miles) in Oceanic basins and 70 km (43.5 miles) in some mountain Ranges of the World.

      the average density of the Continental crust is 2.7 Grams per centimeter Cube. However, the average density of the Oceanic Crust is 3.0 cm3 and the average density of the Mental is 3.3 cm3.

      Composition of Continental Crust

       About 95% of the Continental Curst is composed of Granite and Sedimentary Rocks.

       The remaining 5% is composed of  Volcanic and Plutonic Rock (Such as Basalt and Gibarro), These         rocks are more common in Rift zones and mountain Chains

       More interesting information about continental Crust. 

    Do you know? the Oldest Known rocks which formed about 5.8 Billion Years ago are found on     continental Crust
The Oldest Known Rocks are found in Various Parts of the World such as Greenland, Australia,    Canada, and South Africa.     

      Here are some examples of the Oldest Rocks of the Earth's Crust.

     The oldest known rock formed on the Earth is Acasta Gneiss located Northwest of Canada which formed about 4.03 billion years ago.

    Second, Oldest Rock found on the Earth are Isua supracrustal Belt in Greenland Contains Rocks 3.8 Billion years old.

    Pilbara Craton Rocks Present in western Australia is 3rd the oldest Formed rock on the Earth formed about 3.5 billion years ago.

      Let's Define Granite and Sedimentary Rocks 

      Granite is also called Felsic Rock which is rich in Silica and Aluminum.

      Sedimentary rocks are formed by the Accumulation and composition of Sediments of other Rocks and organic matter.

        b) Oceanic Crust.

·       Oceanic crust surrounds over 71% of its area, most of its surface is composed of Mafic Rocks (Dark-colored Substance Rich in Iron and Magnesium).
·     Although the Oceanic crust occupies about three fourth of the earth's surface, the average thickness of the Oceanic Crust is 07 km (04 miles).

        The average density of the Oceanic crust is 03g/Cm3)

Lithosphere

According to geologists, the lithosphere includes the Earth's Crust, and the outer Cool layer of the Mantle both are called the lithosphere. It is comprised of Solid and Rigid materials.
The thickness of the lithosphere varies from 60 to 150 km (40 -95 miles); the lithosphere is thickest under the continents and thinnest under the oceans.
The lithosphere is comprised of major plates that float on the asthenosphere, as an Ice Burg floats in the Arctic and North Atlantic Oceans.

       How Earth Crust is helpful for Man?

      Earth’s Crust is the Source of the soil on the land, the Source of Salts in the Oceans, the Source of Gases in the Atmosphere, Source of All water found in the Atmosphere, Ocean, and Land (Freshwater Marine water). 

     Composition of the Earth Crust of the Elements

     the composition of the Earth's crust shows that it is primarily composed of eight major elements, which make up more than 98% of its total mass.

  

      What are the 08 Most Common Elements found on the Earth?

     These elements are:- Oxygen (O), Silicon (Si), Aluminum (Al), Iron (Fe), Calcium (Ca), Sodium (Na), Potassium (K), and Magnesium (Mg).

    

      The Most Abundant Elements in the Earhs crus by weight.

   Oxygen is the most abundant element in the Earth's crust, making up about 46.6% of its total mass, while silicon is the second most abundant element in the Earth's Crust, comprising about 27.7% of the crust's mass. The remaining six elements make up the remaining 23.7% of the crust's mass.

            Here is the List of Elements found in the Earth's Crust.

•             Oxygen (46.6%)
•             Silicon (27.7%)
•             Aluminum (8.1%)
•             Iron (5%)
•  Calcium (3.6%)
•             Sodium (2.8%)
•             Potassium (2.6 %)
•             Magnesium (2.1%)

        What are The Most Common minerals found in the Earth's Crust?

      The Three Most common minerals found in the Earth's Crust are Feldspar, Quarts, and Mica.
The Field spar is the Most abundant mineral found in the Earth's Crust, which makes up 41% of the total volume.
Quartz is the Second most abundant mineral found in the Crust. It makes up about 12% of the Crust's volume.

      Mica is the third most abundant mineral, making 6% of the Volume of the Earth's Crust. 

 

     Answer the Following question in the comments 

    As Oxygen is the Most Abundant element in the Earth's Crust, Do you know which is the Most Abundant element in the Universe?

    

        a. Silicon

        b. Nitrogen

        c. Hydrogen

        d. Oxygen