By: Anthony Perkins

The Pangaea Theory Pangaea was a supposed supercontinent made up of all our current continents. Alfred Wegener - In 1912 he came up with the theory Of Pangaea. The name means “all lands.” -He said Pangaea was probably intact Until late Carboniferous period. hist.html

- other than geology he was accomplished in Astronomy, Meteorology and Climatology. These all helped him to come up with his theory/discovery. When Wegener first proposed the idea it was dismissed. - He could not provide an adequate explanation of the forces responsible for continental drift or disprove the theory that Earth was solid and immovable. hist.html

Arthur Holmes - His ideas later assisted in the recognition of Wegener’s theory. - He elaborated on Wegener’s hypothesis. He said that thermal convection affects the mantle. It causes it to heat and cool. Heating and cooling over a period of time can cause a continent to split up and move. - This received little attention at the time it was proposed. hist.html

The theory being discussed at this time was the Contraction theory. - This said that the Earth was once a molten ball and the act of cooling caused some parts of the Earth to fold in on itself. hist.html

Convergent Boundaries Convergent Boundary: A boundary were one plate overrides another one and forces it under. The one pushed under becomes part of the mantle again. Mountain What it causes: - Mountains - Earthquakes - Volcanoes - Trenches Plate: A piece of the broken up lithosphere that floats on the asthenosphere. (top part of Earth.) Boundary: Where two plates meet.

One example of a Convergent Boundary is the Ring of Fire. - A ring of volcanoes around the edges of the Pacific Plate. - due precisely to there being a lot of convergent zones around there. Volcano

Pictures!!! Convergent Boundary Mariana Trench

Divergent Boundaries Divergent Boundary: At a Divergent Boundary two plates move away from each other. As the plates move away from each other mid- ocean ridges are formed because magma forces itself up through the cracks and cools. Mid-Ocean Trench What it causes: - Mid-Ocean Ridges

One example of a Divergent Boundary is