OCSC 2000 - Ocean Basins

Ocean basin

Large topographic depression on the surface of the Earth; >2000m w/ shape and size changing slowly over time

Pangea

A super continent that existed ~250MYA

Alfred Wegener

Suggested theory of continental drift:

• similar rock/sediment composition across continents

• Fossil records

Seafloor Spreading

How is new oceanic crust formed?

Mid Ocean Ridge

Flanks rising to sharp edges that mimic shape of continental edges; valleys running along crest line

Reykjanes Ridge

Part of mid-Atlantic ridge → alternating high (+)/ low (-) magnetic readings

Geographic North Pole

Fixed at the top of Earth’s axis

Geomagnetic North Pole

Shifts with Earth’s magnetic field

Paleomagnetism

Study of Earth’s magnetic field as recorded in rocks, minerals and sediment

Harry Hess

Said ocean floor was broken into large blocks that are relative to one another

Vine and Matthews

New ocean floor/crust constantly formed by intrusion and extrusion of basalt @ mid ocean ridges

Mid ocean ridges, transform faults, deep sea trenches

Earthquake epicenters coincide with…

Lithosphere

Crust and uppermost mantle

Asthenosphere

Layer below lithosphere which is hotter, partially melted and plastic-like

Thermal convection

Driving force of plate tectonics