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What are the different types of rocks ?
What are the different types of rocks ? What purpose are they used for?
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2 Replies
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Rocks are the natural occurring substance containing of one or more minerals. Rocks form the Earth’s outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of magma in the asthenosphere.
Rocks are categorized used 3 types.
1. Igneous rocks- Also known ad magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava.
Igneous rocks occur in a wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust. Igneous rocks are classified according to mode of occurrence, texture, mineralogy, chemical composition, and the geometry of the igneous body. There are relatively few minerals that are important in the formation of common igneous rocks, because the magma from which the minerals crystallize is rich in only certain elements: silicon, oxygen, aluminium, sodium, potassium, calcium, iron, and magnesium. These are the elements that combine to form the silicate minerals, which account for over ninety percent of all igneous rocks.
2. Sedimentary rocks- These are the types of rock that are formed by the accumulation or deposition of mineral or organic particles at the Earth’s surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place.
3. Metamorphic rocks:Metamorphic rocks make up a large part of the Earth’s crust and form 12% of the Earth’s land surface.They are classified by their protolith,their chemical and mineral makeup, and their texture. They may be formed simply by being deeply buried beneath the Earth’s surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction and distortion. -
Igneous rocks: Igneous rocks are the rocks that are formed from an originally hot molten material, through the various process of cooling and crystallization are termed igneous rocks. Igneous rocks are supposed to form after the crystallization and consolidation of magma or lava.
Purpose:
1. Different types of granites are used for geological studies.
2. Diorite is used in buildings as decorative stones and also as aggregate.
3. Andesite is used in buildings as decorative stones and in the paint industry.
Sedimentary Rocks: The pre-existing rocks on the Earth’s surface are eroded continually by natural processes. The sediments that are produced get transported by the natural agencies to the basins where they are deposited, get compacted and consolidated, over a long period of time, and transform into a cohesive solid mass. These solid’s mass is called sedimentary rocks.
Purpose:
1. Sandstones are the ideal rock for groundwater and oil reservoirs.
2. Shale is used to manufacture bricks and tiles.
3. Limestones are the primary source of lime for cement. Cement is considered one of the basic construction materials.
Metamorphic rocks: Metamorphic rocks form from pre-existing igneous, sedimentary, and metamorphic rocks under the conditions of high temperature and pressure. The original texture, composition, and mineralogy of the parent rocks get changed in the new physicochemical and/or tectonic conditions. The process that causes this change is called metamorphism and the resultant rock is called metamorphic rock.
Purpose:
1. Metamorphic rocks are an important source of building materials. Marble is commonly used as a decorative building stone since prehistoric times.
2. White marble is particularly prized as a stone from which to create monuments and statues, such as the famous Taj Mahal.
3. Slate is very useful in building material and finds application in roof tiles, floor tiles, pool tables, blackboards, etc.
