Rocks
Grade 9B
Chemistry Group Presentation
Mr. Bisoon
May 11, 2023
Group Members
01 02
Vivekanad
03
Yuki Clarke Ruth Larson
Makhan
04 05
Kenroy Renuka
Jameer Muniram
Definition!
Before we determine the types of rocks and how they are
formed, we need to have a basic idea of what rocks are
A natural solid mass or collection of minerals or mineraloid
materials is referred to as a rock. According to the processes
that led to the development of a rock, it is typical to classify
rocks into three major categories. They are incredibly small
grains of various minerals that have been chemically
compressed to produce a bigger mass.
01
Igneous
having solidified from lava or magma.
These rocks are created when magma, which is molten rock from
deep within the Earth's crust, makes its way into or onto the
crust and cools and solidifies.
Intrusive igneous rocks are those that are created when lava
cools and hardens within the Earth's crust.
These rocks are typically coarse grained and frequently contain
big crystals since they were created by the gradual cooling of
magma.
Granite and gabbro are a couple of examples of intrusive igneous
rocks.
Examples of Intrusive
Igneous Rocks
Granite Gabbro
Extrusive igneous rocks are created when this lava
swiftly cools and solidifies on the earth’s surface.
The lava cools too quickly for massive crystals to
form, hence these rocks are often fine-grained.
Some examples of extrusive igneous rocks include
basalt and obsidian.
Examples of Extrusive
Igneous Rocks
Basalt Obsidian
02
Sedimentary
that has formed from sediment deposited by water or air.
These rocks are created when sediment that has been
dumped by rivers is compacted over time and turns
into rock. The sea is a common example of a body of
water where this occurs. Layers of the material are
deposited, and the final rock frequently exhibits these
layers clearly. Sandstone and limestone are a few of
examples of sedimentary rocks.
Examples of Sedimentary
Rocks
Sandstone Limestone
How sedimentary rocks are formed:
1.)Weathering
2.)Erosion
3.)Deposit
4.)Compacted
The three ways sedimentary rocks can form are
clastic sedimentation, chemical sedimentary, or
organic sedimentation
03
Metamorphic
that has undergone transformation by heat, pressure, or
other natural agencies,
Metamorphic rocks are formed when there is seismic
movement within the Earth's crust which causes
sedimentary and igneous rocks to be subjected to
high levels of pressure and heat, this changes their
structure and results in the formation of
metamorphic rocks. An example of a metamorphic
rock is marble which is metamorphosed limestone
Example of Metamorphic
Rocks
Marble
04
Rock Cycle
the long, slow journey of rocks down from
Earth's surface and then back up again
After rocks have formed, processes such
as weathering, erosion, plate tectonics Sedimentary and metamorphic
and other geological processes begin to rock may be forced down into
act upon them. As a result of this the the mantle where they melt.
rocks begin to undergo changes. We They may eventually find their
already know that extreme heat and way into the crust and cool
pressure may cause sedimentary and forming intrusive igneous rocks.
igneous rocks to become metamorphic Alternatively, they may erupt out
rock. of a volcano as lava and cool
forming extrusive igneous rocks.
Metamorphic and igneous rocks may be
broken down into small fragments by a
Rocks are constantly being
process called weathering. These
formed, broken down and
fragments may be carried by a river and
deposited in the sea. Over time, layers of reformed in an endless cycle
these fragments may build up and known as the rock cycle.
become compacted forming sedimentary
rock.
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