LITHOSPHERE
It is the outer layer of the Earth and it is made up
of the Crust, part of the Mantle, and Tectonic Plates.
Here we can also find the land masses or continents: Europe,
Asia, America, Africa, Oceania and Antarctica.
TYPES OF ROCKS
Geologist classify rocks into
three basic groups based on how they were formed in nature.
The types of rocks are:
The types of rocks are:
· Igneous
· Sedimentary
· Metamorphic
Igneous comes from the Latin word ‘ignis’ which actually means fire.
Igneous rocks are a word used for rocks that have formed by the cooling of
lava or magma.
The upper
section of the Earth’s crust is made up of around 95% igneous rock.
Those which remain below the surface are called intrusive rocks, while those which cooled on the surface are referred to as extrusive rocks.
Examples
of Igneous Rocks
· Basalt, granite,
pumice and obsidian are examples of igneous rocks.
SEDIMENTARY ROCKS
Sedimentary rocks are formed by sediments that is deposited over time, usually as layers at the bottom of lakes and oceans. This sediment can include minerals, small pieces of plants and other organic matter.The sediment is compressed over a long period of time before consolidating into solid layers of rock.
Examples of sedimentary rocks include limestone, sandstone, mudstone, greywacke, chalk, coal, claystone and flint.
METAMORPHIC ROCKS
Metamorphic
rocks have been changed by extreme pressure and heat.
Metamorphic
rocks can be formed by pressure deep under the Earth's surface, from the extreme
heat caused by magma or by the intense collisions and friction of
tectonic plates.
Examples of
metamorphic rocks include marble, slate, granulite, gneiss and schist.
Marble is a metamorphic rock that is formed from the
sedimentary rock limestone.
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