Theory of Plate Tectonics

1
Theory of Plate Tectonics

• Theory
• Plate Boundaries
• Convergent
• Divergent
• Transform
• Hot Spots

2
What is a SCIENTIFIC THEORY?

• A well tested concept that explains a wide range
  of observations

• In 1965, J. Tuzo Wilson, a Canadian scientist
  proposed the theory of Plate Tectonics
• Combined knowledge of sea-floor spreading with
  continental drift

3
Theory of Plate Tectonics
Late 1900s

• Earths lithosphere is broken into sections
  called plates.
• Plates are always shifting and moving.
• Movement is driven by convection currents in the
  mantle.

Evidence All the evidence collected over the
1900s was used in this theory.
4
Crustal Plates
5
Earth Layers
Earth Layers
6
Convection Currents of Magma
7
Plate Boundary Motion

• CONVERGE - Moving toward one another.
• connecting
• DIVERGE Moving apart.
• dividing
• TRANSFORM Sliding past one another.

Plate Tectonics II Plates, Plate Boundaries,
and Driving Forceshttp//www.visionlearning.com/l
ibrary/module_viewer2.php?mid66llet1Ear
8
Plate Boundaries
http//www.wwnorton.com/college/geo/egeo/flash/2_6
.swf
9
Convergent Boundary
Oceanic Crust Continental Crust

• Features
• Subduction Zone
• Trench
• Volcanic Mountain Arc

Tectonic plates connecting
Narrative and animation by Monte Hieb and Nancy
Hiebmhieb_at_geocraft.com
10
Converging Oceanic Continental Plates
11
Mt. St. Helens,Washington
12
Convergent Boundary
Continental Crust Continental Crust
Tectonic plates connecting

• Features
• Folded Mountains

http//www.pbs.org/wgbh/aso/tryit/tectonics/conver
gent.html
13
Converging Continental Pates
14
Himalayas
15
Convergent Boundary
Oceanic Crust Oceanic Crust

• Features
• Subduction Zone
• Trench
• Island Arc

Tectonic plates connecting
http//www.pbs.org/wgbh/aso/tryit/tectonics/conver
gent.html
16
Converging Oceanic Plates
Subduction Zone
17
Japan island arc
18
Divergent Boundary
Tectonic plate dividing

• Features
• Mid-Ocean Ridge
• Rift Zone

Narrative and animation by Monte Hieb and Nancy
Hiebmhieb_at_geocraft.com
http//www.pbs.org/wgbh/aso/tryit/tectonics/diverg
ent.html
19
Diverging Boundary
20
Transform Boundary
http//www.pbs.org/wgbh/aso/tryit/tectonics/transf
orm.html http//www.wwnorton.com/college/geo/anima
tions/transform_faulting.htm
Plates move in opposite directions on either side
of the transform boundary, causing
earthquakes. Plates move in similar directions on
either side of the fracture zone (red dashed
line), resulting in fewer earthquakes.
21
Transform Fault
San Andreas Fault
22
Hot Spots
Magma has broken through crust as the plate moves
over a spot
http//www.wwnorton.com/college/geo/animations/hot
_spot_volcanoes.htm
http//www.classzone.com/books/earth_science/terc/
content/investigations/es0810/es0810page03.cfm?cha
pter_noinvestigation
23
Additional Animations

• http//www.seed.slb.com/flash/science/features/ear
  th/livingplanet/plate_boundaries/en/index.html?wid
  th570height475popuptrue