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
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,
Snowball earth
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:• __________________
Mid-Ocean Ridges
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.
What is on the bottom of the ocean?
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.
Work in groups 2-4