Plate Tectonics Liz LaRosa for use with my 5th Grade Science Class http://www.middleschoolscience.com 2009

Plate Tectonics Greek – “tektonikos” of a builder Pieces of the lithosphere that move around Each plate has a name Fit together like jigsaw puzzles Float on top of mantle similar to ice cubes in a bowl of water

Tectonic Plates

Pangea? Famous Scientist: Alfred Wegener- German Meteorologist He proposed that the Continents were once a single land mass that drifted apart over time. He called this single land mass supercontinent Pangea, Greek for “all Earth” Wegner proposed this in 1912, but it wasn’t considered to be sufficient evidence in itself. He analyzed either side of the Atlantic Ocean for rock type, geological structures, and fossils.

Evidence of Pangea 1. Puzzle-like fit of the continents.

Evidence of Pangea 2. Fossils of the same plants and animals are found on different continents.

Evidence of Pangea 3. Climate Clues.

Evidence of Pangea 4. Rock clues.

Problems with Wegner’s Theory Wegner couldn’t explain how, when, or why Continental Drift took place.

Sea Floor Spreading

Sea Floor Spreading Mid Ocean Ridges – underwater mountain chains that run through the Earth’s Basins Magma rises to the surface and solidifies and new crust forms Older Crust is pushed farther away from the ridge

How Plates Move http://pubs.usgs.gov/gip/dynamic/unanswered.html

Different Types of Boundaries http://pubs.usgs.gov/gip/dynamic/understanding.html

Divergent Boundary – Arabian and African Plates Arabian Plate Red Sea African Plate

Divergent Boundary – Iceland http://pubs.usgs.gov/gip/dynamic/understanding.html

Divergent Boundary - Oceanic http://www.geology.com

Divergent Boundary - Continental http://www.geology.com

Convergent Boundary – Indian and Eurasian Plates Indian Plate

Convergent Boundary – Oceanic & Continental http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

Convergent Boundary – Oceanic & Oceanic Note – plates are reversed http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

Convergent Boundaries - Continental http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

Transform Boundary – San Andreas Fault www.geology.com

Review Name the 3 main layers of the Earth What is a tectonic plate? What was Pangea? What is Sea-Floor spreading? Name the three different types of plate boundaries and one location on Earth for each one