rocks
TRANSCRIPT
ROCKS
Presented ByMD NURUDDINSURVI SONLB.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 RocksIgneous 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 °CMagma is a mixture of
many minerals
Extrusive and Intrusive rocksAt 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 Rocks Sedimentary 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 shape
Metamorphic rocks “morph” (change) from existing rock, due to heat, pressure and chemicals.
Usually takes place deep in
the Earth
Types of metamorphismRegional 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 RockFoliated - contain aligned grains of flat
minerals
Gneiss is foliated metamorphic rock that has a banded appearance and is made up of granular mineral s.
Metamorphic RockNon-Foliated – mineral grains are not
arranged in plains or bands
Marble is a non-foliated metamorphic rock that is produced from the metamorphism of limestone.
THE ROCK CYCLEThe three types of rocks are very closely
related:Igneous rocks are attacked by erosion and
weathering to form sedimentsCrustal 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