Geography and Oceanography - Chapter 7 docx

Hotspots, Plumes and Mass Extinctions Is Hawaii more than a great vacation spot? How does life respond to geologic catastrophes? Plate Tectonics - Distribution of Volcanic and Earthquake Activity The Earth’s surface is broken into plates Wilson Cycle (ocean basin fm) Examples: 1. East African Rifts 2. Red Sea 3. Atlantic Ocean 4. Pacific Ocean 5. Mediterranean Sea 6. Himalayas, Tibet 1 2 3 4 5 6 [...]... dinosaurs Mass Extinction (K-T Boundary) • What killed the Dinosaurs? • 65 million yr ago • A meteorite, or volcanic activity, or BOTH? Impact Site: Yucatan Peninsula Volcanic catastrophes and Mass Extinctions Greenland • Birth of the Iceland hotspot • Next came the opening of the North Atlantic Ocean basin Global Distribution of large, rapidly-erupted volcanic events red = hotspot-related volcanism since... Initial Plume and Hotspot Activity Mantle Plumes • • • • Part of the circulation in the Mantle Driven by temperature differences Hot and cold => density differences Gravity Rules! http://www.youtube.com/watch?v=f37Gf6IVj6o&feature=related Mantle convection the driving force for plate tectonics What causes the warmer material to rise? Mantle Plumes Mantle convection and hotspot formation Cross-sections... shield volcano Moorea fringing reef Raiatea - barrier reef Bora Bora lagoon Maupiti the oldest volcano next stage is the coral atoll French Polynesia from space atoll barrier reef fringing reef Pacific Hotspot Volcanic Chains Questions: • Where do Hotspots come from? • How do Hotspots start? • How long do they last? Indian Ocean • Hotspot tracks and 3 spreading ridges • A complete record of hotspot... convection the driving force for plate tectonics What causes the warmer material to rise? Mantle Plumes Mantle convection and hotspot formation Cross-sections of the Earth Red = hot upwelling from core-mantle boundary Cold lithosphere sinks, hot plumes rise Cartoon Schematic Blue = cold downwelling Computer Model . Hotspots, Plumes and Mass Extinctions Is Hawaii more than a great vacation spot? How does life respond to geologic catastrophes? Plate Tectonics - Distribution of Volcanic and Earthquake Activity The. Hawaiian Hotspot Volcanoes to atolls (Darwin) Tahiti shield volcano Moorea fringing reef Raiatea - barrier reef Bora Bora lagoon Maupiti the oldest volcano next stage is the coral atoll French. Hotspots come from? • How do Hotspots start? • How long do they last? Indian Ocean • Hotspot tracks and 3 spreading ridges • A complete record of hotspot activity