Plate Tectonics

1
Plate Tectonics
2
Plate Tectonics is a theory that describes the
formation, movements, and interactions of Earths
plates.
3
Alfred Wegener, a German meteorologist, proposed
a hypothesis called Continental Drift in 1912.
4
Continental Drift supposed that the continents
have moved, or drifted, from one location to
another over long periods of time.
5
Continental Drift supposed that the continents
have moved, or drifted, from one location to
another over long periods of time.
6
Wegener based his idea on the following
observations
7
The continents had similar shapes.
8
The same fossils were found in South America and
Africa.
9
Similar rock formations were found in South
America and Africa.
10
Climate Change Areas once covered in glaciers
are now in warmer climate zones.
11
Wegeners idea could not explain how the
continents moved.
12
The Theory of Plate Tectonics suggests that the
continents are part of the lithospheric
plates.Evidence for this
13
Volcano, Earthquake, and Mountain Belts are
located along plate boundaries.
14
The ocean floor gets older away from a mid-ocean
ridge.
15
The rock record shows that the magnetic field of
the Earth has reversed many times.
16
Types of Plate Boundaries
17
Divergent Boundary
Rift Valleys and Mid-Ocean Ridges
18
Convergent Boundary
Deep Sea Trenches, Subduction Zones, and Mountain
Ranges
19
Convergent (2 Types)
20
Convergent Subduction
Less Dense (Continental or Oceanic Crust)
More Dense (Oceanic Crust)
21
Convergent Collision
Equal Density Continental Crust
22
Transform (Strike-Slip) Boundary
San Andreas FaultDivision between North American
and Pacific Plates
23
North American Plate
Pacific Plate
Pacific Plate
North American Plate
San Andreas FaultDivision between North American
and Pacific Plates
24
Types of Plate Boundaries
25
Causes of Plate Movement
26
3 HypothesesMantle ConvectionRidge PushSlab
Pull
27
Mantle Convection The mantle moves the plates
along as it convects (heats from below). Mantle
Convection Animation 2
28
Ridge Push The accumulating magma at a mid-ocean
ridge pushes material away.
29
Slab Pull When a plate subducts, it pulls the
rest of the plate with it.