Plate Boundaries and Plate Boundaries and Plate TectonicsPlate Tectonics

By: Mike Brady, Joe Fassel, Liz By: Mike Brady, Joe Fassel, Liz Alessi, Brittany Spalding, Josh Alessi, Brittany Spalding, Josh

MinnichMinnich

Plate BoundariesPlate Boundaries

-a fracture that separates one -a fracture that separates one plate from anotherplate from another

3 different types3 different types

• Divergent boundary

• Convergent boundary

• Transform boundary

DivergentDivergent

• Forms when two plates move apart from each other, then the underlying asthenosphere oozes upward to fill the gap between the separating plates.

Plates Involved:

Ocean-Ocean Ex) Mid-Atlantic Ridge

Continent- Continent Ex) East African Rift

ConvergentConvergent

• Two lithospheric plates move toward each other, 2 plates of different densities come together and the denser one sinks beneath it.

• Plates Involved:

Ocean-Ocean Ex) Western Aleutians

Ocean-Continent Ex) Andes

Continent-Continent Ex) Himalayas

TransformTransform

• This forms when two plates slide horizontally past on each other as they move in opposite directions.

• Plates Involved:

• Ocean-Ocean Ex) East Pacific Rise• Continent-Continent Ex) San Andreas fault

Short Term Climate ChangeShort Term Climate Change

• Climate change can occur rapidly in a few ways due to plate tectonics.

• Plate tectonics can cause waterways to close or mountains to form.

• This can cause changes in air currents and water currents, which in turn causes climate changes.

Long Term Climate ChangeLong Term Climate Change

• Plate Tectonics can cause extreme changes in climate over a geologically long period of time.

• This occurs when a continent shifts far distances and therefore changes its latitude relative to the equator and the poles.

Sea Floor Spreading Sea Floor Spreading

• Sea floor spreading causes the global climate to change in two ways.

• When the sea floor spreads slowly the Mid-Ocean ridge system is relatively narrow.

• This displaces a relatively small amount of water, and exposes a large amount of marine limestone which, during the process of weathering decreases the amount of CO2 in the atmosphere, and decreases the global temperature.

Sea Floor Spreading Cont.Sea Floor Spreading Cont.

• When the sea floor spreads rapidly the Mid Ocean Ridge system is wider, and displaces a larger amount of water.

• This raises sea level and in turn cuts down the amount of exposed marine limestone.

• Which in turn reduces the amount of CO2 removed through weathering, and increases the global temperature.

Affect of More Lands and at Affect of More Lands and at Higher LatitudesHigher Latitudes

oAlter ocean currents and therefore heat transport

oAlter global atmospheric circulation

oMore glaciers over land, higher albedo, cooler temps

SourcesSources

• http://apollo.lsc.vsc.edu/classes/met130/notes/chapter18/plate_tech.html

• Thompson & Turk, Earth Science and the Environment,3rd Edition.