Geology: Plate Tectonics By: Ms. Kristin Wilkinson

Plate Tectonics Pangea Eurasia North America Africa South America India Australia Plate Tectonics Antarctica

1-2. Continental Drift (Old Theory) Alfred Wegener (1900’s) proposed Continents were once a single land mass that drifted apart called- Pangea Evidence or proof! Fossils of the same plants and animals are found on different continents Called this supercontinent Pangea, Greek for “all Earth.” Continents fit like a puzzle 245 Million years ago Split again – Laurasia & Gondwana 180 million years ago http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml

3. What are Plates? 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

4. Evidence for Continental Drift Fossil Clues Animals Mesosaurus is a reptile found only in S. America & Africa Plant Climate Clues Glacial deposits Rock surfaces Rock Clues A golden orb-weaver spider from the Middle Jurassic Inocaulis Silurian Plant Fossil

Evidence of Pangea

5. Theory of Plate Tectonics Due to the mapping of the ocean floor scientists discovered mid-ocean ridges, thus leading towards this new theory. Seafloor spreading creates new crust along the ridge and older crust is pushed farther away from ridge.

CONVECTION CURRENT!!! 6. How Do Plates Move? Tectonics and Volcanism II http://pubs.usgs.gov/gip/dynamic/unanswered.html

7. Plate Boundaries Divergent Boundaries – plates move AWAY from each other. Convergent Boundaries – plates move TOWARD each other. Transform Boundaries – plates SLIDE past each other.

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

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

Iceland

Divergent Boundary - Oceanic

Divergent Boundary - Continental

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 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? Name the three different types of plate boundaries and one location on Earth for each one

11. Dynamic Earth Forces that Shape Earth Isostasy – the relationship between crust and asthenosphere Vertical Stress Subsidence and Uplift Horizontal Stress Compression Tension Shearing

Dynamic Earth… Slow Changes… Rapid Changes to the Earth’s Surface Earthquakes, Tsunami’s, Volcanic Eruptions Slow Changes… Mountain building, Ridge building, island arcs, Volcanic arcs &hot spots

12. Landforms Created by Compression Mountain ranges Ocean trenches Volcanic arcs Island arcs

13. Landforms Created by Tension Mid-ocean ridges Continental rifts

14. Landforms Created by Shearing Transform Faults