Title: Music today: The Ventures,
1Music today The Ventures, Hawaii Five-O
- Reminder 1st Midterm Exam next Wednesday (April
20) - In class, closed book
- 70 multiple choice 30 short essay
- Study Guide is up on website
2Lecture 8 Hotspots, Plumes and LIPs (Large
Igneous Provinces)
- Is Hawaii more than a good vacation spot?
- How does life respond to catastrophes?
3Plate Tectonics - Distribution of Volcanic and
Earthquake Activity
4Wilson Cycle (ofocean basin fm)
- Examples
- 1. East African Rifts
- 2. Red Sea
- 3. Atlantic Ocean
- 4. Pacific Ocean
- 5. Mediterranean Sea
- 6. Himalayas, Tibet
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6The Hawaiian Hotspot
7Tahiti -- shield volcano
8Moorea -- fringing reef
9 Raiatea - barrier reef
10Bora Bora -- lagoon
11Maupiti -- the oldest volcanonext stage is the
coral atoll
12French Polynesia from space
fringing reef
barrier reef
13Hotspot Volcanic Chains
14Questions
- Where do Hotspots come from?
- How do Hotspots start?
- How long do they last?
15Indian Ocean
- Hotspot tracks and 3 spreading ridges
- A complete record of hotspot activity
16JOIDES Resolution drillship
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18Western India
- An accumulation of lava flows 3 miles thick!
- Occurred at the same time as the dinosaurs
extinction
19Mass Extinction(K-T Boundary)
- What killed the Dinosaurs?
- 65 million yr ago
- A meteorite, or volcanic activity, or BOTH?
20Impact Site Yucatan Peninsula
21Volcanic catastrophes and Mass Extinctions
22Greenland
- Birth of the Iceland hotspot
- Next came the opening of the North Atlantic Ocean
basin
23Global Distribution of LIPs
24Large Igneous Provinces are
- BIG!!
- NOT explained by Plate Tectonics
- Initial Plume and Hotspot Activity
25A Mantle Plume
- A blob of warm material rising from the lower
mantle - Solid but flowing at slow rate (lt1 m/yr)
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27Degassing Magma
- Gases include CO2, SO2, Cl, F that make acid
rain - Shuts down photosynthesis
28Hydrothermal Exchange - Metals
29Effects 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
30Two Styles of Mantle Convection
31Evolution of Life
- Where there is chaos there is opportunity
- Extinctions lead to new ecosystems