Transcript Slide 1
Geology of the Oceans How did we get our oceans? • Have they changed ?____________________ • Oceans formed 4.2 billion years ago – Water vapor escaping from crust condensed on surface – http://www.youtube.com/watch?v=hwVU0-2Qnso&safety_mode=true&persist_safety_mode=1 World Ocean • Origins of life – Organic molecules accumulated in oceans – First cells (anaerobic heterotrophic prokaryotes) evolved in oceans Anaerobic:____________________________________ Heterotrophic:_________________________________ Prokaryotes:___________________________________ 3.5 billion year old marine prokaryotic fossils 3.0 billion year old marine stromatolites 600 million year old prokaryotes similar to cyanobacteria (photosynthetic) Where did the salt come from in the oceans? • The chlorine combined with the water molecules to make_______________. After falling to the ground with rain water and flowing over the surface, the acid gnawed at rocks, stripping them of their salts, particularly sodium. Some of the sodium atoms combined with chlorine atoms to form________________—more commonly known as table salt—____________________. • http://www.youtube.com/watch?v=w_8mw-1HYFg&safety_mode=true&persist_safety_mode=1 World Ocean • Covers__________________ • Four main basins—Pacific, Indian, Atlantic, Arctic—and the Southern Ocean • Other divisions – Seas – gulfs Continental Drift • Continental crust vs. Oceanic crust: What is the difference?___________________________ ____________________________ ____________________ • Going back to slide 2 Do oceans change and how? http://www.youtube.com/watch?v=PoV4qSwg7nc&safety_mode= true&persist_safety_mode=1 Continental Drift • _____________________________________ _____________________________________ __Erupting magma – Midocean ridges – ridge systems • • • • Subduction zones: ________________ Seafloor spreading _________________ ____________________________ • • • • _____ of the continental boundaries ________________ of earthquakes ________________ of the sea bottom _______ of rock samples from the seafloor: young/old • Analysis of core samples drilled through the ocean sediments. What is on the bottom of the ocean? Ocean Basin • Abyssal Plains and Hills • Seamounts • Ridges and Rises • Trenches – Island arcs – Marianna Trench Composition of Sea Floor • ____________Sediment • ____________Sediment – Calcareous ooze – Siliceous ooze (glass) • ____________ Sediment – Mud • ____________Sediment – Iron rich Rift Communities • Rift communities, or deep-sea vent communities • 1977 • Food webs in absence of sunlight Aliens of the deep Movie the open oceans • http://www.youtube.com/watch?v=mrSu65Bb9X4& safety_mode=true&persist_safety_mode=11 • Watch the video and list any organisms that you can identify and what criteria you used to identify them: • __________________________________________ __________________________________________ __________________________________________ Work in groups 2-4 • 2. Volcanoes, mid-oceanic ridges, and deepsea vents are all associated with ___________ • 3.How can there be a food web with out light? • 4. Why are sedimentary rocks that exist on the ocean bottom much younger than any similar rocks found on the continents?