Plate Boundaries Continental Drift Review Breakup of Pangaea

Plate Boundaries

Continental Drift Review • Breakup of Pangaea • Future Plate Movement Animation

Sea Floor Spreading • http: //www. classzone. com/books/earth_sci ence/terc/content/visualizations/es 0803 page 01. cfm? chapter_no=visualizatio n

What causes plates to move? A- Ridge push- Material from mid-ocean ridges pushes the plates B- Convection Currents- in the mantle, molten rock rises, cools, then sinks, pushing the plates with the current C- Slab Pull- Gravity pulls cooler, denser plates into mantle

Diagram

Plate Boundaries • Convergent- “coming together” • Divergent- “separating” • Transform- “scraping past”

Convergent Boundaries • There are 3 types: – Continental-Continental – Continental-Oceanic – Oceanic-Oceanic

Continental-Continental Collisions • Responsible for creating… – continental mountain ranges • Examples: – Himalayas – The Alps

Continental-Continental Collisions DIAGRAM Convergent boundary MANTLE (Asthenosphere) Mountain Range

2 converging continental plates

Continental-Oceanic Collisions • Also called a Subduction zone • Responsible for creating… – Volcano ranges – Oceanic Trenches (write this in) • Example: – Cascade Range (WA and OR) – Andes mountains

Continental-Oceanic Collisions Diagram Trench Oceanic Plate MANTLE (Asthenosphere) Continental Crust

Convergent boundary -subduction zone-

The Andes Mountains Trench

Oceanic-Oceanic Collisions • Responsible for creating… – Volcanic Island Chains – Oceanic Trenches • Examples– Japan, The Phillipines – Mariana Trench in the Pacific Ocean

Oceanic-Oceanic Collisions Diagram Trench Oceanic Plate MANTLE (Asthenosphere) Oceanic Plate

http: //www. platetectonics. com/book/images/Convergence 2. gif

http: //www. dkimages. com/discover/previews/875/20120887. JPG

Mariana Trench- http: //upload. wikimedia. org/wikipedia/commons/1/13/Mariana_trench_location. jpg

Divergent Boundaries “When plates go their separate ways…”

Divergent Boundaries • Occur when two tectonic plates separate from each other • Responsible for – Sea-floor spreading – Mid-ocean ridges – Rift valley (on land) • Examples: Mid-Atlantic Ridge (oceanic); Great Rift Valley (E. Africa)

Divergent Boundary Parting is such sweet sorrow… Diagram PLATE MANTLE (Asthenosphere)

Divergent boundary -Two plates move apart- Animation http: //www 2. nature. nps. gov/GEOLOGY/usgs nps/animate/A 48. gif

Mid-Atlantic Ridge

Great Rift Valley earth. imagico. de/views/eafrica_large. jpg

Transform Boundaries “friction never felt so good” (unless you live in California)

Transform Boundary • Occur when two tectonic plates scrape past each other horizontally • Responsible for most earthquakes – Earthquakes can occur at any plate boundary • Example: San Andreas Fault, CA

Transform Boundary Diagram

San Andreas Fault, CA http: //nationalatlas. gov/articles/geology/features/images/sanandreas. jpg

http: //pubs. usgs. gov/gip/dynamic/graphics/San_Andreas. gif

Wrapping Up • http: //www. classzone. com/books/earth_sci ence/terc/content/visualizations/es 0804 page 01. cfm? chapter_no=visualizatio n