1. History of the Oceans G.Burgess2009.

2. Formation of the UNIVERSE 4.5 billion years ago, the universe began as an explosion (Big Bang Theory) Materials radiated outward from the explosion and cooled As particles cooled they formed a disk of gas, dust and ice As the particles spun, they collided –Some stuck and formed larger particles –The particles formed planets

3. Formation of the EARTH Cataclysmic bombardment of particles and planetesimals cause Earth to form a molten mass Crust cools and forms plates with fissures and cracks Denser materials travel to center of Earth –Formation of iron/ nickel core (iron catastrophe –Lighter materials travel to surface (silicates form continents (granite), basalts form ocean floor Inner heat causes volcanoes, vents, and subduction zones, Mid-Atlantic Ridge along plate boundaries. Earth develops layers; inner core, outer core, mantle, crust

4. Formation of the OCEANS Volcanic action of Earth releases dust, gas and debris from inner crust and top of mantle. Water vapour escapes, cools, collects and condenses on the atmosphere. Condensed water falls to the Earth and collects in lower parts forming oceans

5. Differences in crustal zones Continental crust: –continents float like icebergs on mantle –Contain rocks made with silicon (ie. granite, mica, quartz, feldspar, etc.) Oceanic crust: –much denser than continental crust –Has little to no silicon in rock materials, ie. basalt –Much thinner than continental crust. –Thinnest point ~15 mls from mantle –More calcium than materials in mantle

6. Plate tectonics Study of the movement of the crustal plates Continual shifting causes oceans to form and collapse Atlantic Ocean is getting larger, while Pacific Ocean is getting smaller How super continents are formed. –First; Rhodinia, Last; Pangaea –N. and S. America fit into European and African Continent –Himalayas were formed from India colliding with Asia

7. Continental Drift and the Oceans As continents move apart, oceans are formed As continents collide and form super continents, oceans collapse Mid-Atlantic Ridge: upwelling of material from mantle pushes ocean wider Change in ocean spread changes ocean depth, currents and circulating of heat in the ocean

8. References Ocean THE WORLD’S LAST WILDERNESS Fabien Cousteau, American Museum of Natural History 2006.