Challenger expedition 1872-1876

Woods Hole, Massachusetts Hopkins Marine Station, Stanford

Scripps Institute of Oceanography Friday Harbor Labs, Washington

Submersibles

R/V FLIP, floating instrument platform

Scientific Method

• What?

• Why?

• How?

Inductive approach: from specific observations to the general

Deductive approach: use general principles in predicting specific outcomes

Ocean Basin Geography

Interconnected World Ocean system

How did we get these ocean basins?

• Continental drift– all the continents had once been joined in a

single ‘supercontinent’ called Pangaea • Plate tectonics• Sea floor spreading

Mid Ocean Ridge• Continuous chain of submarine volcanic

mountains encircling the globe– Largest geological feature on earth– Is not static; slips and slides

Sea floor spreading

• As ridges separate, molten mantle rises up through rift

Moving plates

Collisions

• Creates trenches or subduction zones– Earthquakes &

volcanos– Less dense continental

crust floats on top; lasts forever

– Form volcanic islands

Kilauea, Hawai’i