plate tectonics and geological structures

Paleomagnetism

Magnetic minerals line up wit the earths magnetic fields

This proves the tectonic theory

Sea floor spreading

Causes deep sea ridges along plate boundaries

Most notable in the Atlantic Ocean

Harry Hess proposed the idea in 1962

Constructive plate margins

New crust created at mid ocean ridges

New oceans created at major rifts

Spreading varies from 1-10 cm per year

Destructive plate boundaries

Oceanic crust destroyed at deep ocean trenches (or subduction zones)

Oceanic-continent collision: deep trench or subduction zone associated with volcanic mountain chain. Synonymous of earthquakes and volcanos as well as landslides and tsunamis

Ocean-ocean collision: deep trench or subduction zone associated with volcanic island arc. Synonymous of frequent volcanic eruptions and large scale earthquakes

Continent-continent collision: plates collide and rise up creating fold mountains such as the Himalayas. Often causes large, devastating earthquakes and landslides

Conservative plate boundaries

Plates move past each other laterally

No creation or destruction of crust

Plates can stick leading to a build up of stress that is eventually released as an earthquake when the fault slips or ruptures.