Layers of the Earth

Major Layers

• Lithosphere
  • Outermost layer comprising the crust and the solid part of the mantle.
  • Known as the crust in traditional earth science studies.
• Asthenosphere
  • Located just under the lithosphere.
  • Characterized by its semi-liquid state that allows for movement.
  • Contains convection currents responsible for tectonic plate movements.
• Core
  • Divided into the inner core (solid) and outer core (liquid).

Earth Structure and Plate Tectonics

• The earth is composed of several plates, including the African, South American, and Pacific plates.
• Plates are named based on their geographical location (e.g., African Plate surrounding Africa).
• Plates are responsible for geological features such as volcanoes and trenches, depending on their movements.
• California is an example of a region sitting on multiple plates (Pacific and North American plates).
• Movement of plates is driven by convection currents in the asthenosphere due to temperature and pressure variations.

Convection Currents

• Occur within the asthenosphere due to heat from the core.
• Hot material rises, cools at the surface, and then sinks, creating a cycle.
• This movement facilitates the drift of tectonic plates.
  • Example: A lava lamp illustrates convection currents as heated liquid rises, cools, and falls.

Oil Formation

• Oil is located in the lithosphere (crust).
• Formed from organic matter trapped between plates over millions of years.
• Requires high pressure and temperature to transform organic materials into fossil fuels.
• Plates moving together or apart contribute to the heat and pressure needed for fossil fuel formation.
• Fossil fuels are named because they originate from decomposed organic matter (fossils).