PLATE TECTONICS A Moving Experience!!!

What is “Plate Tectonics”? A theory that describe the formation, movements, and interactions of the earth’s tectonic plates The plates ARE NOT the continents

Early Ideas Continental drift –developed by Alfred Wegener The continents moved around Shapes seemed to fit together Similar fossils on separated continents Rock formations matched up Climate change evidence

Problems with Cont. Drift How do the continents move? Why? What powers them? Wegener only had a theory, but no supporting evidence.

Support of Plate Tectonics Earthquakes and volcanoes seem to occur in a pattern Magnetic evidence at the mid-ocean ridge Chain of mountains at the mid-ocean ridge

Divergent Boundaries Divergent boundary-plates move apart forming rift valleys Sea floor spreading occurs at mid-ocean ridges

Convergent Boundaries 2 plates moving towards one another is a convergent boundary When 1 plate is forced underneath another, subduction occurs, with the more dense plate going below the less dense plate (Subduction Boundary) This often forms a deep-sea trench

Collision Boundary 2 continental plates smashing into one another forming one larger continent The crust is forced upward resulting in a mountain chain India crashing into Asia has caused the Himalaya Mountains

Transform Boundary 2 plates sliding past one another form a transform boundary San Andreas Fault in California is a very active Transform Boundary

The Past in Plate Tectonics Pangaea is the name given to the giant land mass when all the continents were together Pangaea was around about 2.5 billion years ago