Energy in the lithosphere

Geothermal energy within the earth is created from the radioactive decay of elements in the core. This energy drives convection currents in the lithosphere where some of this energy reaches the surface (e.g. Volcanoes, Hot Springs, Geysers). Geothermal energy makes up 0.001% of the earths energy budget, the rest comes from the sun.

Potential Energy:

1. Radioactive elements contain energy in their nucleus and release it as the breakdown into atoms. This energy drives convection currents in the earth's core and mantle, where it is transformed into kinetic energy
2. Plants which are buried suddenly cannot decompose and their chemical energy can be stored as coal, gas, or oil, storing supplies of energy that originated as light millions of years ago. This chemical energy is released when the coal, gas or oil is burned.

Kinetic Energy:

1. The earth's plates all move as the upwelling magma circulates in the mantle.
2. Hydro thermal vents in the ocean and hotspots (e.g. Yellowstone, Hawaii)

Chemical Energy:

1. Available from fossil fuels (coal, gas and oil)

Plate Tectonics

Plate Tectonics occur due to convection currents in the upper mantle (semi-liquid), which cause the earth's crustal plates to move. This is called continental drift. Plates move up to 1 - 8 cm per year.

Continental drift:

The lithosphere consists of two different crust types.

1. Oceanic Crust
       A continuous shell of Basalt (Dense)
       5-8 km thick
       Composed of:
           Silica & Magnesium (SIMA)
           Simatic material => Basalt
       
       Oceanic crust forms below the earth's oceans
   
2. Continental Crust
       Lighter (Less Dense) layer of Granite
       20-40 km thick
       Composed of:
           Silica & Aluminum (SIAL)
           Sialic material => Granite
   
       Continental crust forms on the earth's surface.
   

Isostacy

Isostacy: The theory that accounts for the rising and falling of mountains

The earth's crustic plates float on top of a semi-liquid Asthenosphere according to their density. More dense plates will have an average depth lower than less dense plates. Since oceanic plates are composed of simatic material, they have an average depth lower than continental plates (which are composed of sialic materials)

Plate Movement

Horizontal - Due to spreading (mid-oceanic ridge) centers along upwelling convection cells
Vertical - Isostatic movement due to increased weight (e.g. DOWN - Adding of Ice, sediments, etc; UP - Removal of material)