Music today The Ventures Hawaii FiveO Reminder 1

Lecture 8: Hotspots, Plumes and LIPs (Large Igneous Provinces)

Plate Tectonics - Distribution of Volcanic and Earthquake Activity

Wilson Cycle Examples: 1. East African Rifts 2. Red Sea 3. Atlantic Ocean 4.

Maupiti -- the oldest volcano next stage is the coral atoll

Questions: Where do Hotspots come from? n How do Hotspots start? n How long

The Indian Ocean Hotspot tracks and 3 spreading ridges n A complete record of

Western India F An accumulation of lava flows 3 miles thick! F Occurred at

Mass Extinction (K-T Boundary) F What killed the Dinosaurs? F 65 million yr ago

Greenland F Birth of the Iceland hotspot F Next came the opening of the

Large Igneous Provinces are: F BIG!! F NOT explained by Plate Tectonics F Initial

A Mantle Plume A blob of warm material rising from the lower mantle n

Degassing Magma F Gases include CO 2, SO 2, Cl, F that make “acid

Effects of Submarine Plateaus F Release of “reduced” metals uses up oxygen in the

Biologic Evolution F Where there is chaos there is opportunity F Extinctions lead to

Slides: 30

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Music today: The Ventures, “Hawaii Five-O” Reminder: 1 st Midterm Exam next Monday (April 19) n In class, closed book n 70% multiple choice; 30% short essay n Study Guide is up on website n

Lecture 8: Hotspots, Plumes and LIPs (Large Igneous Provinces)

Plate Tectonics - Distribution of Volcanic and Earthquake Activity

Wilson Cycle Examples: 1. East African Rifts 2. Red Sea 3. Atlantic Ocean 4. Pacific Ocean 5. Mediterranean Sea 6. Himalayas, Tibet n

The Hawaiian Hotspot

Tahiti -- shield volcano

Moorea -- fringing reef

Raiatea - barrier reef

Bora -- lagoon

Maupiti -- the oldest volcano next stage is the coral atoll

Hotspot Volcanic Chains

Questions: Where do Hotspots come from? n How do Hotspots start? n How long do they last? n

The Indian Ocean Hotspot tracks and 3 spreading ridges n A complete record of hotspot activity n

JOIDES Resolution drillship

Western India F An accumulation of lava flows 3 miles thick! F Occurred at the same time as the dinosaurs’ extinction

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

Impact Site: Yucatan Peninsula

LIPs and Mass Extinctions

Greenland F Birth of the Iceland hotspot F Next came the opening of the North Atlantic Ocean basin

Global Distribution of LIPs

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

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

Degassing Magma F Gases include CO 2, SO 2, Cl, F that make “acid rain” F Shuts down photosynthesis

Hydrothermal Exchange - Metals

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

Two Styles of Mantle Convection

Biologic Evolution F Where there is chaos there is opportunity F Extinctions lead to new ecosystems