Transcript Plate Tectonics and Plate Boundaries

Plate Boundaries and
Plate Tectonics
By: Mike Brady, Joe Fassel, Liz
Alessi, Brittany Spalding, Josh
Minnich
Plate Boundaries
-a fracture that separates one
plate from another
3 different types
• Divergent boundary
• Convergent boundary
• Transform boundary
Divergent
• 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
Convergent
• 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
Transform
• 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 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 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 causes the global climate to
change in two ways.
• When the sea floor spreads slowly the MidOcean 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.
• 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
Higher Latitudes
o Alter ocean currents and therefore heat
transport
o Alter global atmospheric circulation
o More glaciers over land, higher albedo,
cooler temps
Sources
• http://apollo.lsc.vsc.edu/classes/met130/n
otes/chapter18/plate_tech.html
• Thompson & Turk, Earth Science and the
Environment,3rd Edition.