Sam Videlock
BASALT AND THE OCEANIC CRUST
BACKGROUND INFORMATION
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The Oceanic crust is made up of three layers.
1st Layer – consists of unconsolidated or semi consolidated
sediments, sometimes including volcanic ash.
2nd Layer – Layer two is about 2 kilometers thick mostly made
up of glassy Basalt.
3rd Layer – this layer is formed by slow cooling of magma. About
five kilometers thick.
•The
Volcanoes that create
Basalt are very common, and
they tend to form in ocean
basins.
• This is a main reason why
Basalt is so common inside of
the oceanic crust, because all of
the cooling magma sinks into
the crust, and dries there,
creating magma to enter the
crust.
•Picture
•http://lh4.ggpht.com/_3b1u2R
PUEmA/R6S15mIlSiI/AAAAAAAA
Alw/HeaLyK5wApM/Lava+Ocea
n+Entry_Volcanoes+NP,+Big+Isl
and,+Hawaii.jpg
HOW MAGMA AND BASALT GET INTO THE OCEANIC CRUST
HOW THE LAVA DRIES
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When The basaltic lava erupts under
the sea, the lava will cool very quickly.
Leaving a flexible skin on the
surface, but still molten inside. The
molten lava will soon break up into
separated groups, until it settles and
dries.
In the picture to your right, this is
under water lava flow.
Pictures –
http://oceanexplorer.noaa.gov/explorations/06fi
re/background/volcanism/media/pillow_lava_6
00.jpg
MORE FACTS
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Most black sand beaches, like the
ones in Hawaii are formed when hot
basalt lava flows into the sea and is
shattered into many fragments when
the rock chills.
This is similar to the underwater lava
flow drying process.
The picture to the right shows a black
sand beach, and when you really
look, you can see the small fragments
of basalt rock.
Picture
http://www.cs.berkeley.edu/~artin/Pictures/Ha
waii2005/MauiBlackSandBeach1.jpg
PAHOEHOE
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As the hot flowing magma begins to
cool under water, it forms a skin like
texture that distorts, and stretches into
rope like shapes, this is called,
Pahoehoe.
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This picture shows Pahoehoe.
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Picture
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http://upload.wikimedia.org/wikipedia/commons/
8/89/Ropy_pahoehoe.jpg
THANK YOU FOR WATCHING MY POWERPOINT ON
BASALT AND THE OCEANIC CRUST