ROCKS Presented By MD NURUDDIN SURVI SONL B.TECH(BIOTECH) SHARDA UNIVERSITY
What are Rocks? A rock is a naturally occurring solid mixture of one or more minerals, or organic matter Rocks are classified by how they are formed, their composition, and texture Rocks change over time through the rock cycle
Igneous Rocks Igneous rock begins as magma. Igneous rock is formed through the cooling and solidification of magma or lava. Magma freezes between 700 °C and 1,250 °C Magma is a mixture of many minerals
Extrusive and Intrusive rocks At the surface, lava hardens to form extrusive rocks with tiny crystals or glassy texture. Beneath the surface, magma hardens to form intrusive rocks with easily visible crystal texture.
Sedimentary RocksSedimentary rocks form when sediments harden into rocksThree Types:1. Clastic: formed from fragments of other rocks.2. Chemical: formed from mineral grains that come out of solution.3. Organic: formed from the remains of plants/animals.
Metamorphic Rock Meaning to change shapeMetamorphic rocks“morph” (change) fromexisting rock, due to heat,pressure and chemicals. Usually takes place deep in the Earth
Types of metamorphism Regional Metamorphism: large areas of rock are under intense heat/pressure, which occurs during mountain-building. Contact Metamorphism: when hot magma forces itself into overlying rock (intrusions) and bakes the rock
Metamorphic Rock Foliated - contain aligned grains of flat mineralsGneiss is foliatedmetamorphic rockthat has a bandedappearance and ismade up of granularmineral s.
Metamorphic Rock Non-Foliated – mineral grains are not arranged in plains or bandsMarble is a non-foliatedmetamorphic rockthat is producedfrom themetamorphism oflimestone.
THE ROCK CYCLEThe three types of rocks are very closely related: Igneous rocks are attacked by erosion and weathering to form sediments Crustal movements can cause deep rocks to reach high temperatures and to melt back into magma Igneous and sedimentary rocks exposed to intense heat and pressure can become metamorphic