Physical Geology 1330 Dr. Mike Murphy 116-S&R 1 mmurphy@mail.uh.edu Plate Tectonics 333-S&R-1

www.uh.edu/~mamurph2/homepage.html 1. A model explaining how the Earth works. 2. A set of ideas explaining the observed motion of Earth’s lithosphere through the mechanisms of subduction and seafloor spreading, which in turn, generate Earth’s major features, including continents and ocean basins. Plates: Seven Major Plates are recognized:

1. North American, .2 South American, 3. Pacific, 4. African, 5. Eurasian, 6. Australian, 7. Antarctic

Plate Boundaries – Three main types: Divergent Boundary – where plates move apart, resulting upwelling of material from the mantle to create new seafloor Convergent Boundary – where plates move together resulting in the subduction (consumption) of oceanic lithosphere into the mantle. Transform Boundary – where plates slide past each other without the production or destruction of lithosphere. The Wilson Cycle •Embryonic Stage - E African Rift Valley •Immature Stage - Red Sea •Mature Stage - Atlantic Ocean •Declining Stage - Pacific Ocean •Remnant Stage - Mediterranean Ocean •Suture Stage - Himalayan Mountains

Fig. 20.17a

Fig. 20.17b

Fig. 20.17d

Continent-Continent Collision Result in: 1. 2. 3. Isostasy •Buoyancy of low-density rock masses “floating on” high-density rocks; accounts for “roots” of mountain belts

Transform Boundary – where two plates slide past one another without the production or destruction of crust. The fault defining the boundary is called a transform fault. Examples of Transform faults: 1. 2. Driving Mechanisms of Plate Tectonics 1. 2. 3.