Earth dynamics

Earth dynamicsEarly theories: Continental Drift

The origin of EarthEarth increased its mass and started to create a gravitational force which was also increasing. Great collisions with other orbiting planets created the Earths great internal energy.Elements organized by densities due to the action of gravity upon them and creating layers.Outer layer cooled and formed a crust.

Internal structure of the Earth

Compositional layersCrustMantleCore

Physical layersLithosphere (rigid)Asthenosphere (ductile mantle, and partially molten)Lower mantle (solid, but flexible)Outer Core (liquid)Inner core (solid)

Movement of continentsMany people believed continents were fixed. However there was controversy.

Do they move?If they move.how and why do they move?

Continental movementIce Age theoryContinental Drift Theory Early 1900sPlate tectonic theory - 20th century

Ice Age theory

Movement of continents19th-20th centuries some believe continents were fixed. Alfred Wegener was the first to collect evidence to explain that continents had previously been joined. He wrote the Continental drift theory 1912

Continental drift theoryContinents are made of lighter crust.This crust slides over a continous thicker layer. This layer made up the ocean floor and continued under the continents.All continents were once joined into a supercontinent he named Pangea.

Continental Drift theoryEvidence:Geological evidence: Continents fit together like a puzzle along their coastlines and continental shelves.

Continental Drift theoryEvidence: Palaeolithic evidence. Identical fossils of land-based organisms in continents that are far apart.

Continental Drift theoryEvidencePalaeoclimatic evidence: continents that would have been at high latitude in Pangea, have glacial morraines from that age. Same occurs with large coal deposits in Northern hemisphere areas, which indicate tropical forests once there.

He didnt clearly explain HOW they moved.