Plate Tectonics The Earths Crust in Motion Earths

Plate Tectonics The Earth’s Crust in Motion…

Earth’s Structure Crust (about 3 - 43 miles thick) Mantle (about 1, 790 miles thick) Inner Core (about 750 miles thick) Outer Core (about 1, 410 miles thick) Lithosphere (crust and upper mantle) broken into tectonic plates

The Theory of Plate Tectonics In 1910 Alfred Wegener begins to wonder… What’s the relationship between the continents? Perhaps all these pieces used to be connected. He develops theory of Continental Drift the belief that continents are slowing moving over the Earth’s surface 300 million years ago…

Pangea The Supercontinent Tens of Millions of years!

How does it work? Plates – pieces of the lithosphere Plates fit closely together along cracks called Plate Boundaries Plate movement is caused by convection currents in the mantle Plates move at a rate of a few centimeters a year

We live here

How Plates Move • Divergent Move away from each other • Convergent Move toward each other • Transform Slide past each other

Divergent

Convergent

Transform

A Divergent • plates are moving apart • new crust is created • Magma is coming to the surface B Convergent • plates are coming together • crust is returning to the mantle C Transform • plates are slipping past each other • crust is not created or destroyed

A Divergent Continental crust rift valley B Convergent 2 continental plates mountain range C Transform Plates move against each other Stress builds up Oceanic crust midocean ridge 2 oceanic plates or oceanic + continental subduction Stress is released earthquake

The Big Picture