Plate Interactions Tectonic Plate Theory Definition of Plate

Plate Interactions Tectonic Plate Theory

Definition of Plate Tectonics is theory that Earth’s lithosphere is broken into about 20 plates that move on top of the asthenosphere.

Map of the Plates

Questions 1 -3 Use the map to answer the following questions. Put your answers on the back of the map. 1. What is the name of the plate that we live on? 2. About where on the plate is New York City (on the edge, near the edge, in the middle)? 3. What cities in the United States are on the edge of a plate?

The Plates Are Moving! Evidence to Support Plate Tectonics 1. Puzzle-like fit of continents

Shape of Continents

The Plates Are Moving! Evidence to Support Plate Tectonics 1. Puzzle-like fit of continents 2. Fossils of same species of plants and animals on various continents, across oceans

Fossil Evidence

The Plates Are Moving! Evidence to Support Plate Tectonics 1. Puzzle-like fit of continents 2. Fossils of same species of plants and animals on various continents 3. Glacial grooves that match across continents

Glacial Grooves

The Plates Are Moving! Evidence to Support Plate Tectonics 1. Puzzle-like fit of continents 2. Fossils of same species of plants and animals on various continents 3. Glacial grooves that match across continents 4. Coal in cold climates

Coal in Antarctica

The Plates Are Moving! Evidence to Support Plate Tectonics 1. Puzzle-like fit of continents 2. Fossils of same species of plants and animals on various continents 3. Glacial grooves that match across continents 4. Coal in cold climates 5. Earthquake boundaries that match the tectonic plate boundaries

Earthquakes Looking at the boundaries of earthquakes around the world… http: //www. iris. edu/seismon/ There is a lot in common to those plate boundaries!!!

Questions 4 -7 Use the map to answer the following questions. Put your answers on the back of the map. 4. Between the west coast of the North American plate and the northeastern part of the Pacific plate, the plates are moving in what way? 5. What do we have a lot of in this part of the world? 6. Between the African Plate and the South American plate, the arrows show the plates moving in what way? 7. What do you think might be occurring there?

More Evidence: Seafloor Spreading

Visualization of Sea. Floor Spreading http: //www. classzone. com/books/earth_science/terc/con tent/visualizations/es 0803 page 01. cfm? chapt er_no=visualization

Questions 8 -10 Use the map to answer the following questions. Put your answers on the back of the map. 8. Between what two plates would seafloor spreading be happening? 9. What does this do to the size of the ocean floor? 10. What force makes the magma rise up through cracks in the seafloor?

Types of Plate Boundaries • Convergent (Coming Together) • Divergent (Dividing Apart) • Transform (Slipping Past)

Converge!

Diverge!

Transform!

Convergent Boundaries • Definition: Two plates move into one another • Two Types of Convergent Boundaries 1. Continent to Continent 2. Subduction Zone

Subduction Zone

Subduction Zone Formation of Andes Mountains Ü Nazca plate is moving under South American plate - this is called subduction Ü Nazca plate is ocean crust and therefore more dense, it sinks below the continental crust Question 11: What is a subduction zone?

Continent-to-Continent Collisions

Continent-to-Continent Collision…. Formation of Himalayas Ü Indo-Australian plate moved into Eurasian plate Ü Eurasian plate began to crumble up Ü Over millions of years, Himalayas were built and continue to grow today Question 12: Why have geologists found fish fossils at the top of the Himalayas?

Divergent Boundaries • Definition - when two plates move apart • Example: Mid. Atlantic Ridge • Ocean floor is growing as the plates move apart

Transform Boundary

Ring of Fire

Hot Spots - Volcanoes in the middle of plates