Produced and Presented by Ryan Hiscoke - PowerPoint PPT Presentation

Title: Produced and Presented by Ryan Hiscoke


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The Rock Cycle

• Produced and Presented by Ryan Hiscoke

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The Rock Cycle Explained
The Rock Cycle is a group of changes. Igneous
rock can change into sedimentary rock or into
metamorphic rock. Sedimentary rock can change
into metamorphic rock or into igneous rock.
Metamorphic rock can change into igneous rock or
sedimentary rock.
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Igneous Rock
Igneous rocks are sometimes called the mother
of all rocks because they are the first type of
rock formed after a volcanic eruption. Igneous
rocks are formed when magma breaks through the
crust and pours lava over the surface. When this
cools it forms hard rock known as igneous rock.
Granite is an example of an igneous rock and the
size of its crystals tells us how quickly it
cooled. If the magma in the underground pockets
cool slowly the crystals will be large. But if
the lava above ground cools quickly small
crystals will form. Igneous rocks are hard and
always have crystals in them. Igneous rocks never
have fossils in them because they come from magma
and anything near it would disintegrate
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Some examples of how different types of Igneous
rock were formed
Pumice Pumice rocks are igneous rocks which were
formed when lava cooled quickly above ground. You
can see where little pockets of air had been.
This rock is so light, that many pumice rocks will
actually float in water. Pumice is actually a
kind of glass and not a mixture of minerals.
Because this rock is so light, it is used quite
often as a decorative landscape stone. Ground to
a powder, it is used as an abrasive in polish
compounds and in Lava soap.
Granite Granite rocks are igneous rocks, which
were formed by slowly cooling pockets of magma
that were trapped beneath the earth's surface.
Granite is used for long lasting monuments and
for trim and decoration on buildings
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Sedimentary Rock
When Rocks erode and become washed away. The
particles are called sediment. These little
particles of sediment are washed downstream where
they eventually settle to the bottom of the
rivers, lakes, and oceans. Layer after layer of
sediment is deposited on top of each other. Over
time these layers are compressed down more and
more through time, until the bottom layers slowly
turn into rock.
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Some examples of sedimentary rock and their uses
Gypsum Gypsum rocks are sedimentary rocks made up
of sulphate mineral and formed as the result of
evaporating seawater in massive prehistoric
basins. It is very soft and is used to make
Plaster of Paris, casts, melds, and wallboards.
Limestone Limestone rocks are sedimentary rocks
that are made from the mineral calcite, which
came from the beds of evaporated seas and lakes
and from sea animal shells. This rock is used in
concrete and is an excellent building stone for
humid regions.
Sandstone Sandstone rocks are sedimentary rocks
made from small grains of the minerals quartz and
feldspar. They often form in layers as seen in
this picture. They are often used as building
stones.
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Metamorphic rock
Metamorphic means change in form. Sometimes
igneous and sedimentary rocks may get buried deep
underground. The heat and pressure of Earth
cooks and twists the rock. It changes into a
new type of metamorphic rock. If you examine
metamorphic rock samples closely, you'll see how
flattened some of the grains in the rock are.
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Some examples of how different types of
Metamorphic rock were formed
Gneiss These rocks may have been granite, which
is an igneous rock, but heat and pressure changed
it. You can see how the mineral grains in the
rock were flattened through
tremendous heat and pressure and are arranged in
alternating patterns.
Schist
These rocks can be formed from basalt, an igneous
rock like shale, a sedimentary rock or a
metamorphic rock like slate. Through tremendous
heat and pressure, these rocks were transformed
into this new kind of rock.