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Music today: The Ventures, “Hawaii Five-O”

Music today: The Ventures, “Hawaii Five-O”. Reminder: 1st Midterm Exam next Wednesday (April 26) In class, closed book 70% multiple choice; 30% short essay Study Guide is up on website. Lecture 8: Hotspots, Plumes and LIPs ( L arge I gneous P rovinces).

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Music today: The Ventures, “Hawaii Five-O”

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  1. Music today: The Ventures, “Hawaii Five-O” • Reminder: 1st Midterm Exam next Wednesday (April 26) • In class, closed book • 70% multiple choice; 30% short essay • Study Guide is up on website

  2. Lecture 8: Hotspots, Plumes and LIPs (Large Igneous Provinces) Is Hawaii more than a good vacation spot? How does life respond to catastrophes?

  3. Plate Tectonics - Distribution of Volcanic and Earthquake Activity

  4. Wilson Cycle (ofocean basin fm) • Examples: 1. East African Rifts 2. Red Sea 3. Atlantic Ocean 4. Pacific Ocean 5. Mediterranean Sea 6. Himalayas, Tibet

  5. The Hawaiian Hotspot

  6. Tahiti -- shield volcano

  7. Moorea -- fringing reef

  8. Raiatea - barrier reef

  9. Bora Bora -- lagoon

  10. Maupiti -- the oldest volcanonext stage is the coral atoll

  11. French Polynesia from space atoll fringing reef barrier reef

  12. Volcanoes to atolls after Darwin

  13. Hotspot Volcanic Chains

  14. Questions: • Where do Hotspots come from? • How do Hotspots start? • How long do they last?

  15. Indian Ocean • Hotspot tracks and 3 spreading ridges • A complete record of hotspot activity

  16. JOIDES Resolution drillship

  17. Western India • An accumulation of lava flows 5 km thick! • Occurred at the same time as the extinction of the dinosaurs

  18. Mass Extinction(K-T Boundary) • What killed the Dinosaurs? • 65 million yr ago • A meteorite, or volcanic activity, or BOTH?

  19. Impact Site: Yucatan Peninsula

  20. Volcanic catastrophes and Mass Extinctions

  21. Greenland • Birth of the Iceland hotspot • Next came the opening of the North Atlantic Ocean basin

  22. Global Distribution of LIPs

  23. Large Igneous Provinces are: • BIG!! • NOT explained by Plate Tectonics • Initial Plume and Hotspot Activity

  24. A Mantle Plume • A blob of warm material rising from the lower mantle • Solid but flowing at slow rate (<1 m/yr)

  25. Degassing Magma • Gases include CO2, SO2, Cl, F that make “acid rain” • Shuts down photosynthesis

  26. Laki, Iceland (1783) -- the year without a summer

  27. Hydrothermal Exchange - Metals

  28. Ocean Anoxic Events (OAEs)productivity or preservation?

  29. Hydrothermal Plumes from LIPs

  30. Effects of Submarine Plateaus • Release of “reduced” metals uses up oxygen in the oceans • Trace metals are “nutrients”, so promote rapid growth of plankton • Sinking organic matter also uses up oxygen in the oceans • Extinctions of marine organisms

  31. Two Styles of Mantle Convection

  32. Evolution of Life • Where there is chaos there is opportunity • Extinctions lead to new ecosystems

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