Earth structure
- Created by: selemo
- Created on: 14-10-16 14:51
View mindmap
- Structure of the Earth
- Inner core
- Depth of 5,150-6,370 kliometers.
- Made of solid iron and nickel.
- suspended in molten outer core.
- Solidified as result of pressure-freezing.
- Outer core
- Depth of 2,900-5,150 Kilometers.
- Hot, electrically conducting liquid (mainly Iron and Nickel.)
- Secondary type seismic waves can't pass through the outer core as it is a liquid.
- Conducting layer combines with Earth's rotation to create dynamo effect.
- Maintains a system of electrical currents.
- Creates Earth's magnetic field.
- Responsible for subtle jerking of Earth's rotation.
- Not as dense as pure molten Iron, indicates presence of lighter elements.
- 10% of the layer is composed of Sulfur and Oxygen.
- Lower Mantle
- Depth of 650-2,900 Kilometers.
- Composed mostly of silicone, magnesium and oxygen.
- Also contains Iron, Calcium and Aluminium.
- Scientists assume Earth has similar proportion and abundance of cosmic elements as found in the Sun.
- Upper Mantle
- Depth of 10-400 Kilometers.
- Solid fragments of mantle found in eroded mountain belts and volcanic eruptions.
- Olivine and Pyroxene have been found.
- Olivine (Mg,Fe)2SiO4
- Pyroxene (Mg,Fe)SiO3
- These and other minerals are crystalline at high temperatures.
- Part of upper mantle called Astheno-sphere is partially molten.
- Oceanic Crust
- Depth of 0-10 Kilometers.
- Ocean Ridge System, a 40,000 kilometer network of volcanoes.
- Generates new crust at the rate of 17 Km cubed per year.
- Covers ocean floor with igneous rock called basalt.
- Hawaii and Iceland are examples of accumulation of basalt islands.
- Continental Crust
- Depth of 0-75 Kilometers.
- Composed, essentially of crystalline rocks.
- Low density, buoyant minerals.
- Dominated mostly by Quartz and feldspars (metal-poor silicates.)
- Crust is the surface of the Earth.
- Cold rocks deform more slowly, refer to the rigid outer shell as the Lithosphere.
- Inner core
Comments
No comments have yet been made