Classification of Rocks - Igneous Rocks and Sedimentary Rocks

Important facts about igneous rocks and sedimentary rocks

What is a rock called?

Substances found in the upper crust or crust of the earth, whether they are hard in nature as granite and sandstone or soft as chalk or sand; Whether it is permeable like chalk and limestone or impervious like slate, it is called rock or rock. Their composition is a mixture of different types of minerals. A rock is sometimes formed by only one mineral, but it is usually a combination of two or more minerals. Here is a list of important facts about igneous rocks and sedimentary rocks. Based on Igneous Rocks and Sedimentary Rocks, some questions are definitely asked in every exam, so it is very important for your all type of exam preparation.

Types of Rocks:

(1) Igneous Rocks: Igneous rocks are formed by the formation of hot and liquid rocky material beneath the surface, i.e. magma, formed above the surface in the form of lava flows or before being ejected in order to rise above the surface. It is due to the freezing of these molten materials at the bottom and solidification. Therefore, igneous rocks are formed by the freezing of molten rock material. It can also be ravenous. These rocks together with the other two major rocks found on Earth, sedimentary and metamorphic, form the three major types of rocks found on Earth.

• The word igneous is derived from the Latin word 'ignis', which in general means fire.
• Igneous rocks are loose, hard compaction and fossil-free.
• These rocks are considered economically very prosperous.
• Magnetic iron, nickel, copper, lead, zinc, chromite, manganese, gold and platinum are found in these rocks.
• They are also called 'primary rocks' due to their formation first in the origin of the earth's surface.
• When the lava ejected from the ground at the time of volcanic eruption turns into igneous rocks after cooling down hard on the surface, it is called extrusive or volcanic rock.
• When the rising magma comes to the surface of the surface and freezes inside the ground before coming out, it is thus called an intrusive rock.
• About 90% to 95% of the igneous rocks and metamorphic rocks are found in the upper 16 kilometers (10 mi) of the Earth's crust.
• Igneous rocks are classified according to the mode of occurrence, texture, mineralogy, chemical composition and geometry of the igneous body.
• Valuable mineral ores are found only in igneous rocks.
• The mica found in Jharkhand, India is found in these rocks.
• Igneous rocks are hard rocks, which are also fibrous and granular.
• Chemical weathering has little effect on these rocks.
• No fossils of any kind are found in them.
• The vast majority of igneous rocks are found in volcanic regions.
• Iron, nickel, gold, lead, platinum are found in abundance in igneous rocks.
• The iron content of basalt rock is high.
• Black soil is formed by the breakdown of basalt rock.
• Bituminous coal is an igneous rock.
• Coal, graphite and diamond are called allotropes of carbon.
• Graphite is also called pencil lead.

These rocks are further metamorphosed due to heat, pressure, and chemical reactions. Some examples of igneous rocks:- The main examples of igneous rocks are granite, basalt, gabbro, obsidian, diorite, dolorite, andesite, peridotite, felsite, pitchstone, pumice, etc. Types of Igneous Rocks: There are three types of igneous rocks.

1. Plutonic rock
2. Hupabisal rock
3. Vulcanic rock

(2) Sedimentary Rocks: Sedimentary rock refers to the small rocks formed by the factors of nature, deposited in a place, and in a later period, by pressure or chemical reaction or other factors, in the form of a layer like solid. These are called 'sedimentary rocks'. Sedimentary rocks can be formed by water, wind or glacier, any factor. On this basis, the sedimentary rocks are of 'water', 'vayudha' and 'glacial' type. Sandstone, limestone, slate, marble, lignite, anthracite are sedimentary rocks. In other language, the continuous weathering and fracturing of pre-existing rocks occurs due to the constant blows of wind, water and snow. The materials available from this type of erosion are pebbles, stones, sand, soil etc., carried by streams, wind or glaciers, often collect in lowlands, ocean, lake or river valleys. Over time, they become stratified by condensing. These stratified rocks are called sedimentary rocks.

• Sedimentary rock is flaky.
• Fossils are found in sedimentary rocks.
• Mineral oil is found in sedimentary rocks.
• Anthracite coal contains more than 90% carbon.
• Lignite is considered to be the best variety of coal.
• Sedimentary rocks are mostly found in flaky form.
• Fossils of flora and fauna are found in large quantities in them.
• Iron ore, phosphate, coal, peat, sandstone and cement making rock are found in these rocks.
• Mineral oil is found in sedimentary rocks.
• If a layer of penetrating rock comes between two layers of impervious rocks, favorable conditions are created for mineral oil.
• Coal is found in the sedimentary rocks of Damodar, Mahanadi and Godavari river basins.
• The Agra Fort and the Red Fort of Delhi are made of sedimentary rocks called sandstone. The major sedimentary rocks are sandstone, chika shale, limestone, chalk, salt etc.

Sedimentary rocks metamorphose to form quartzite. Types of Sedimentary Rocks: There are three types of sedimentary rocks.

• Detrital or Epiclastic Rocks: These rocks are formed by the breaking and gathering of various minerals and boulders due to physical causes. The sand and clay dissipated by various natural shocks, carried by rivers or gusts of wind, collect in suitable sites and give rise to the first type of rocks. Such rocks are called detrital or epiclastic rocks. Sandstone or Shale are such rocks.
• Chemical Rocks: These rocks are formed by the chemical precipitation of substances dissolved in water. Filtration is of two types, either by mutual reactions of substances dissolved in water or by evaporation of water. Such rocks are called chemical rocks. Various carbonates, such as limestone, dolomite, etc., phosphates and various salts come in this category.
• Organisms have a hand in the development of the third type of rocks. After death, the hard remains of coral (coral), algae (algae), shelled waterfowl, diatoms, etc., collect together to form rocks. This is how coal is formed from the accumulation of dead vegetation. The cooperation of bacteria in the formation of chemical rocks is remarkable. The removal of dissolved substances in water is accelerated by the stimulation of micro-organisms.

3. Metamorphic Rocks: Metamorphic rock is formed due to change or transformation due to heat and pressure in igneous and sedimentary rocks. Metamorphic rocks (metamorphic rocks) make up a large part of the earth's crust and are classified by composition, chemical and mineral composition. Some examples of sedimentary rocks

• Shell - Slate
• Chosen Stone - Marble
• lignite-anthracite
• Slate - phyllite
• Phyllite - cyst

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