The Earth’s Crust

Pages 148-150

 

·        The thinnest, outermost layer.

·        Made up of Sedimentary, Igneous and Metamorphic rock

·        The rocks on the upper crust are mostly sedimentary

·        Two types of Crust:

·        Oceanic Crust: The crust found beneath the Oceans

o       It is called the Sima (made mostly of Basalt-a darker, heavier igneous rock)

o       It is thinner (only 8 km)

o       Made mostly of silicon, oxygen and magnesium

o       Heavier and more dense

·        Continental Crust: The crust found on the continents and at the beginning of the oceans

                   (continental shelf):

o       It is called the Sial (made mostly of Granite-a light colored igneous rock)

o       It is thicker (especially in mountainous areas)

o       Made mostly of Silicon, Oxygen, Aluminum, Iron, Calcium, Sodium and Potassium

o       Lighter and less dense

 

All life on Earth exists on or within a few hundred meters of the crust