Plate Tectonics What exactly is a plate One
- Slides: 20
Plate Tectonics
What exactly is a plate? • One of the moving, irregularly shaped slabs that make up the lithosphere • Floats on asthenosphere
Explain the Theory of Continental Drift • Proposed by Wegener (1912) • 200 -250 million years ago, Pangea began breaking apart
Pangea • http: //www. youtube. com/watch? v=GYVS_ Yh 6 d. Tk
Evidence of Pangea • 1. Fossil Evidence • 2. Rock Evidence • 3. Coastlines fit like puzzle pieces • 4. Mountain ranges match up.
What is the Earth made up of? • Crust – 5 – 100 km thick • Mantle – 2, 900 km thick • Core – 3, 430 km thick
5 Layers • • • Lithosphere – 15 -300 km Asthenosphere – 250 km Mesosphere – 2550 km Outer Core – 2200 km (Liquid!) Inner Core – 1230 km (solid!)
What type of boundary moves apart? • 1. Divergent – plates move APART • Produces – Earthquakes, volcanoes, and new crust • Example: Iceland / Mid-Atlantics Ridge (in ocean)
Divergent Boundary
Divergent • http: //www. youtube. com/watch? v=t-ctk 4 KR -KU
Subduction • Subduction is the process by which oceanic crust sinks beneath a deepocean trench and back into the mantle at a convergent plate boundary. – The denser material will sink beneath the less dense material.
What type of boundary moves together? • 2. Convergent – together • There are 3 types of Convergent boundaries
Types of Convergent Boundaries • A. Ocean – Continent: has a trench • Produces – large earthquakes, volcanoes and mountains • Examples: Andes Mountains
Types of Convergent Boundaries • B. Ocean – Ocean: has a trench • Produces: earthquakes and volcanoes • Example: Aleutian Islands
Types of Convergent Boundaries • C. Continent to Continent • Produces: mountains and small earthquakes • Example: the Himalayas, India & Eurasia
Convergent • http: //www. youtube. com/watch? v=ep 2_ax AA 9 Mw
What is the third type of boundary? • 3. Transform Boundary: plates moving side by side • * Crust is neither created nor destroyed • Produces: Earthquakes • Example: San Andreas Fault
Transform Boundary
Fault • Fracture in the earth’s crust caused by movement of tectonic plates • Most cause Earthquakes • Example: San Andreas Fault
Tectonic Boundaries