BASALT AND THE OCEANIC CRUSTSam Videlock

BACKGROUND INFORMATION 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.

HOW MAGMA AND BASALT GET INTO THE OCEANIC CRUST

•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/_3b1u2RPUEmA/R6S15mIlSiI/AAAAAAAAAlw/HeaLyK5wApM/Lava+Ocean+Entry_Volcanoes+NP,+Big+Island,+Hawaii.jpg

HOW THE LAVA DRIES 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/06fire/background/volcanism/media/pillow_lava_600.jpg

MORE FACTS

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/Hawaii2005/MauiBlackSandBeach1.jpg

PAHOEHOE 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.

This picture shows Pahoehoe.

Picture http://upload.wikimedia.org/wikipedia/

commons/8/89/Ropy_pahoehoe.jpg

THANK YOU FOR WATCHING MY POWERPOINT ON BASALT AND THE OCEANIC CRUST