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Geology of the Oceans. Did we always have oceans?_____. Have they changed ?___________ Oceans formed between 4.2-3.8 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.
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Did we always have oceans?_____ • Have they changed ?___________ • Oceans formed between 4.2-3.8 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
After the ocean formation • 3.6 billion years of simple cells (prokaryotes) • 3.4 billion years of stromatolites demonstrating photosynthesis, SNOWBALL EARTH • 2 billion years of complex cells (eukaryotes) • 1 billion years of multicellular life,
Continental Drift: Creation of oceans Do oceans change?___ how?_____________ ___________________
World Ocean • Covers 70.8% of Earth’s surface • Four main basins—Pacific, Indian, Atlantic, Arctic • 1. Which ocean is the largest?_______ • 2. Which ocean is between North America and Europe?________ • 3. Which ocean is Bordered by Africa, Australia, India? ______________
Geology of the Oceans • Continental crust vs. Oceanic crust: What is the difference?_______________________
Continental Drift • Magma & convection currents drive continental movement • Erupting magma • Midocean ridges • ridge systems • Subduction zones: • __________________ • Seafloor spreading: • __________________
Ocean Basin • Abyssal Plains and Hills • Seamounts • Ridges and Rises • Trenches • Island arcs • Marianna Trench
Evidence for Continental Drift • Fit of the continental boundaries • Distribution of earthquakes • Temperature of the sea bottom • Age of rock samples from the seafloor: young/old • Analysis of core samples drilled through the ocean sediments.
Rift Communities • Rift communities, or deep-sea vent communities • 1977 • Food webs in absence of sunlight
Composition of Sea Floor • Hydrogenous Sediment • Biogenous Sediment • Calcareous ooze • Siliceous ooze (glass) • Terrigenous Sediment • mud • Cosmogenous Sediment • Iron rich
Aliens of the deep • Watch the video and list any organisms that you can identify and what criteria you used to identify them.