Send the link below via email or IMCopy
Present to your audienceStart remote presentation
- Invited audience members will follow you as you navigate and present
- People invited to a presentation do not need a Prezi account
- This link expires 10 minutes after you close the presentation
- A maximum of 30 users can follow your presentation
- Learn more about this feature in our knowledge base article
How igneous rocks are made
Transcript of How igneous rocks are made
How are they made?
Where are they found?
What are the different types? Igneous rocks are made from rock which has cooled
from molten (melted) rock Where is the temperature hot enough
for rock to be melted? Magma .....or molten rock is found under the crust
where pressure and temperature
are very high.
To understand why the magma
comes to the surface,
............. we need to
understand plate tectonics The Earth's crust floats on
liquid magma. The crust is
broken into plates, which
move, towards each other
or pull apart.
The North American Plate
and the Eurasian Plate
are moving apart.
This weakens the crust
and magma comes to the
This forms volcanoes, and lava
Let's look at an eruption Eyjafjallajokull
This is a volcano in
south Iceland which erupted in April
of this year.
It produced enormous quantities
of ash which stopped flights across the world for
six days. The volcano is now also producing lava. lava crater vent magma chamber Basalt forms when
very quickly in
lava flows. It
has very small crystals.
Granites form when
magma cools underground.
It cools slowly, so large
crystals can form Obsidian forms
when magma cools
so quickly it forms
glass with no crystals Pumice forms when
magma is cooled quickly
trapping gas bubbles.
It can be so light that it
will float on water lava flow this is how the eruption started with
a fissure (split) with fountains of magma
and a lava flow magma chamber lava flow vent cone dyke sill so how do rocks form? What might happen next in
Iceland? On the last three occasions that
Eyjafjallajokull erupted, a much bigger
volcano was triggered.
.....this is Katla, a very active volcano which
erupts every 40 to 80 years. The last eruption
took place in 1918. An eruption is overdue!
It will cause massive flooding in Iceland as
it will melt the glacier that covers it. It could
put so much ash into the atmosphere that it
will block sunlight for a year or more. By Maggie Capon