Plate Techtonics

>CONTINENTAL DRIFT By Michael, Anderson<

Presentation

Continental Drift

Continental drift is the movement of the Earth's continents relative to each other by appearing to drift across the ocean bed. The speculation that continents might have 'drifted' was first put forward by Abraham Ortelius in 1596. The concept was independently (and more fully) developed by Alfred Wagner in 1912. The theory of continental drift was superseded by the theory of plate tectonics which builds upon and better explains why the continents move.


A German scientist Alfred formed this idea of Continental Drift. He argued that today's continents once formed a single landmass, which he named Pangea (Greek for "all land"). It broke into pieces due to the weaknesses in the earth's crust as they were made up of less dense materials, which drifted centimeter by centimeter over millions of years until they arrived at where they are now.

Seafloor Spreading

The seafloor spreading happens when the seafloor gets hot, less dense material below Earth's crust rises toward the surface at the mid-ocean ridges. Then, it flows sideways, carrying the seafloor away from the ridge in both directions. The subduction zone is when it goes under the continental crust and melts into magma. The young rocks are made in the middle (made from seafloor spreading) and the old ones are right by the continents. Because of the seafloor spreading it cause the magnetic reversal the change North to South. The oceanic crust from from the magma coming.


Founded by Harry hess

This was founded by Harry Hess.