Plate tectonics

The theory that a supercontinent called Pangea once existed, and split into smaller pieces and drifted apart

Alfred Wegener

1) Fit of the continents 2) Fossil Correlation 3) Rock types and structures 4) Ancient Climates

the suggestion that Earth’s rotation caused continents to drift in a westward motion, and that larger continents broke through the oceanic crust

He mapped the fit of the continents by using the Continental shelves instead of the actual coastlines

Arthur Holmes

proposed the Sea Floor Spreading hypothesis

Convection Currents in the asthenosphere, and the Seafloor Spreading hypothesis provided evidence for a mobile earth

“Earths crust is divided into approximately twenty rigid slabs called tectonic plates, and as plates move, the continents are carried on top like a conveyor belt.”

put forth the idea that Earth consisted of several fragments called plates

A massive, irregularly shaped slab of solid rock, with edges known as boundaries

Basaltic in composition

granitic in composition

long ridges that occupy the middle of the Atlantic ocean and the eastern part of the pacific ocean

deep trenches along the margins of continents

plates move apart, molten rises from the mantle to create new ocean floor

plates move together, causing one slab of lithosphere to be consumed as it descends beneath the overriding plate

plates move past eachother in opposite directions

1) Earthquakes and volcanoes 2) Paleomagentism 3) Polar Wandering 4) Magnetic reversals and seafloor spreading 5) Ocean Drilling 6) Hot Spots

compressional forces cause plates to move together, one slab of lithosphere is subducted into the mantle

compressional forces cause an ocean plate and a continent plate to move together

a general term that refers to all changes in the original form and/or size of a rock body

That which tends to put a stationary object in motion

the amount of force applied to a given area