Environmental Science 4

Lithosphere

Rigid outermost layer of the Earth. Crust and uppermost mantle. It covers the whole Earth surface which allows other interactions of the other geospheres to happen

Lithos

The greek word that means rocky or stone

Joseph Barrell

Earth's rigid outer crust rests on a semi-plastic layer, proposing the names lithosphere for the former and asthenosphere for the latter

Asthenosphere

Uppermost semi-solid layer of the mantle just under the lithosphere. Soft and provides a lubricant for the plates to move

Oceanic Crust

Thin, 7km thick, composed of basalt. Denser than the other crust.

Continental Crust

Mainly composed of granites and made out of land. This has a layer of igneous and sedimentary rocks

Oceanic Lithosphere

This is composed of MAFIC and ULTRAMAFIC

Magnesium and Iron

MAFIC

90% Magnesium and Iron

ULTRAMAFIC

Crust

Outermost layer of the Earth, composed of both oceanic and continental crust. Life exists here.

2.8-3.0 g/cm and 30 km

Average Density and Average Thickness of the Crust

Mantle

Made out of Silicate rich in Iron and Magnesium

2.7 g/cm and 30-2900 km

Average Density and Thickness of Mantle

83% and 68%

Total Volume of Mantle and Total mass of Mantle on Earth.

Mohorovicic Discontinuity

Boundary between crust and mantle.

4.3-11 g/cm and 2900-6371 km

Average density and average thickness of the core

Outer core

The liquid layer made up of iron and nickel

Inner core

The solid layer mostly iron. 10% of the total magnetic field.

Weichart Gutenberg Discontinuity

Boundary between mantle and core

Plate Tectonics

Earth’s surface is divided into thick plates

Alfred Wegener

He proposed the theory of Continental Drift. He believed that there was a large land mass called Pangea 200 million years ago.

Supercontinent

Pangea is dubbed as the

Harry Hess

Theory of Seafloor Spreading

Divergent Boundary

Two plates moving away from each other

Convergent Boundary

Two plates moving towards each other

Transform Boundary

Two plates sliding horizontally passed one another

1-10 cm per year

This the rate of the movement of plates

Northern Hemisphere

Laurasia: North America, Asia, Europe, Greenland

Southern Hemisphere

Gondwanaland: South America, Africa, Australia and India

India

This became a subcontinent because of the Himalayan Mountain Range.

Mountain Ranges

Convergent Boundary: Continental to Continental

Subduction Zone

Convergent Boundary: Continental to Oceanic

Oceanic Trenches, Volcanic Arcs

Convergent Boundary: Oceanic to Oceanic

Aleutian Islands

Oceanic Trench

Mid-Atlantic Ridge

Divergent Boundary makes

Faults

Transform Boundary