The Ocean Floor

Continental Margins

• Active versus Passive margins

Plate Tectonics & Sea Floor Features

• Mid-ocean ridges

• Trenches

• Other

Hot Spots

• Stray mantle plumes

• Intra-plate volcanoes

• Chains of volcanic seamounts & islands

• Movement direction

• Ex.: Hawaii and its islands

History of the World’s Oceans

• Wilson Cycles (500-600 my)

• Pangea

• Triassic

– Rift valley

- Tethys

• Late Jurassic

– North Atlantic

History of the World’s Oceans

• K/T Boundary

– Loss of Tethys

– Asteroid impact

• Modern World

– 3 major oceans

– Southern Ocean

Continents and Oceans

• Modern Mountains and Oceanic Influences

– Ice Ages??

• Continents through time - accretion

• Stable interior of continents = cratons

Characteristics of the Sea Floor

• Geography of the Sea Floor

– Just as diverse as on land

Bathymetry of the Sea Floor

• Continental Margins

• Active versus passive

• Continental Shelf

• Shelf break

• Slope

• rise

Continental Margins

• Submarine Canyons

– How do they form?

– Turbidity currents

– Turbidites - graded bedding

– Continental Rise

Ocean Basin Floor

• Abyssal Plain

• Abyssal Hills and Seamounts

– Guyots - how do they form?

Ocean Basin Floor

• Tectonic Features on the Sea Floor

– Ocean basins compartmentalized