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Earth’s Crust

Earth’s Crust. Unit Notes. Layers of the Earth. Crust. The Crust is the layer that we live on It is the most widely studied and understood Split into two parts: oceanic crust and continental crust A bout 60 km thick under a continent and 5 km thick under the ocean .

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Earth’s Crust

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  1. Earth’s Crust Unit Notes

  2. Layers of the Earth

  3. Crust • The Crust is the layer that we live on • It is the most widely studied and understood • Split into two parts: oceanic crustand continental crust • About 60 km thick under a continent and 5 km thick under the ocean. • Only accounts for 1% of the Earth’s make-up.

  4. Mantle • The mantle is the second layer of the earth. • The mantle has the biggest volume of all the layers, the volume of it is 84% of the earth. • It is 1,800 miles deep or 2,900 kilometers deep. • In the mantle are convection currents which make the mantle move. • The lower mantle heats up and rises and cools down then gets pushed down because it is heavier.  • The mantle grows a meter a year.

  5. Outer Core • The outer core is liquid • Made up primarily of iron and nickel • The temperature of the outer core is 4400 degrees C • The depth of the core is 2980 meters • It is believed the core is rotating faster than the rest of the Earth • Discovered in 1936 by a seismologist

  6. Inner Core • The Inner crust is the second thinnest layer. • The inner core is hotter than the surface of the sun, or 5505 degrees Celsius • The inner core isalso made out of iron and nickel. • It is 5159 to 6378 km thick. • It is a solid because of all the pressure from the other layers putting there weight onto this layer. • The inner core grows. The core was discovered in 1971..

  7. Continental Drift Theory(Basic Points): • According to the theory of continental drift, the world was made up of a single continent through most of geologic time. That continent eventually separated and drifted apart, forming into the seven continents we have today. • The first comprehensive theory of continental drift was suggested by the German meteorologist Alfred Wegener in 1912. • The hypothesis asserts that the continents consist of lighter rocks that rest on heavier crustal material—similar to the manner in which icebergs float on water. • Wegener contended that the relative positions of the continents are not rigidly fixed but are slowly moving—at a rate of about one yard per century.

  8. Continental Drift Theory(Proofs): • The way the continents seem to fit together like a jigsaw • The similarity of fossils and plant remains on opposite continents. • The similarity of rock structure on opposite coastlines • Geologic features (such as mountains) line up. • Evidence that suggests the polar regions of the Earth have been moving, or wandering • Climate patterns agree with Continental Drift in several ways

  9. Continental Drift Theory(Problems): • The main problem with Continental Drift Theory is that it cannot adequately explain what would cause gigantic land masses to drift in the first place. • The theory also doesn’t really account for the existence or purpose of volcanoes • The theory also cannot explain the reason we get Earthquakes • The theory does not incorporate modern ideas about convection and seismology.

  10. Plate Tectonic Theory(Basic Points): • Scientists believe that Earth's surface is broken into a number of shifting slabs or plates, which average about 50 miles in thickness. • These plates move relative to one another above a hotter, deeper, more mobile zone at average rates as great as a few inches per year. • Most of the world's active volcanoes are located along or near the boundaries between shifting plates and are called plate-boundary volcanoes. • The boundary along where most major volcanoes appear is named the ‘Ring of Fire’

  11. Plate Tectonic Theory(Proofs): • Explains the formation of mountains and mountain ranges (Plates collide and the land pushes upwards) • Explains the formation of volcanoes and why they release molten rock (magma)(Plates pull apart leaving space for magma to bubble upwards) • Explains why we get earthquakes(Plates rub against each other causing shaking) • Explains why we get deep ocean trenches(Plates collide and one plate slides under the other) • Uses modern scientific information to support its claims

  12. Plate Tectonic Theory(Problems): • Does not account for many of the points that Continental Drift Theory seems to • If the continents are sitting on separate plates, than they could not have been a super continent, and they could not have left all the fossils and plant remains that support the Drift Theory. • There are mountains and volcanoes on the interior of some plates – how did they get there?

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