Lecture 3 - Plate Tectonics

Lecture 3

where do you find volcanos

Divergent and Convergent (LEAST at transform)

Divergent plate formation

plates pull apart so get thin, rift, mantle upwells into a ridge. Oceanic crust (basalt) formed from this shows record of reversals of magnetism thru paleomagnetism. (Magnetite points north always, comes from volcanos to). Rifting above sea level - Iceland.

Convergent Plates

Push together older/ocean crust goes under newer/continental crust. When just 2 continental push together - crustal thickening (ex Himilayas). When 2 oceanic push together - one subducts, creating volcanic island arcs and deep trenches, like the Marianas Trench

Transform Boundaries

Plates slide past each other. Connect segments of mid ocean ridges. Example - San Andreas Fault in California

What is the most common mineral group in the crust

Feldspars

How many tectonic plates on earth

12

what moves tectonic plates

Mantle convection currents

Examples of divergent boundaries

Prominent examples of divergent boundaries include the Mid-Atlantic Ridge (oceanic separation) and the East African Rift Valley (continental separation)