terminology the term “plate” refers to the subdivision of the earth’s crust and lithosphere....
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TerminologyTerminology The term “plate” refers to the subdivision of the earth’s The term “plate” refers to the subdivision of the earth’s
crust and lithosphere.crust and lithosphere.
The term “tectonics” refers to the deformation of the The term “tectonics” refers to the deformation of the earth’s crust.earth’s crust.
““Plate tectonics” refers to the formation and migration of Plate tectonics” refers to the formation and migration of these plates.these plates.
Subduction zone is where two plates come together, and Subduction zone is where two plates come together, and one is forced below the other.one is forced below the other.
It is puzzling!It is puzzling! Alfred Wegener developed a Alfred Wegener developed a
theory that states that all theory that states that all present continents were once present continents were once together and collectively together and collectively known as a 'supercontinent' known as a 'supercontinent' called a Pangaea.called a Pangaea.
The Pangaea theory was The Pangaea theory was treated with much skepticism treated with much skepticism when it was first raised. But when it was first raised. But since then, there have been since then, there have been much evidence to support this much evidence to support this theory. theory.
There are 3 types of boundaries:There are 3 types of boundaries: Divergent plate boundariesDivergent plate boundaries
Convergent plate boundariesConvergent plate boundaries
Transform plate boundariesTransform plate boundaries
Divergent plate boundariesDivergent plate boundaries Divergent plate boundaries are where two plates move apart or Divergent plate boundaries are where two plates move apart or
separateseparate
Magma is heated by convection, rises and pushes the plates apartMagma is heated by convection, rises and pushes the plates apart
This creates a new sea floorThis creates a new sea floor
Also called seafloor spreadingAlso called seafloor spreading
Rifts and RidgesRifts and Ridges Great Rift Valley in Great Rift Valley in
AfricaAfrica
Mid-Atlantic RidgeMid-Atlantic Ridge
Back to boundary types
Convergent BoundariesConvergent Boundaries This is where two plates come togetherThis is where two plates come together One plate is forced to sink below the otherOne plate is forced to sink below the other Subduction zone Subduction zone There are three types of convergent boundaries:There are three types of convergent boundaries:
• Ocean-continentOcean-continent• Ocean-oceanOcean-ocean• Continent-continentContinent-continent
Back to types of boundaries
Oceanic-continentalOceanic-continental The subduction zone is where the oceanic plate is forced below The subduction zone is where the oceanic plate is forced below
the continental plate.the continental plate.
A deep trench is formed off shoreA deep trench is formed off shore
A mountain range is formed on landA mountain range is formed on land
An example is the West coast of North AmericaAn example is the West coast of North America
Back to convergent boundaries
Oceanic-OceanicOceanic-Oceanic Where two oceanic plates Where two oceanic plates
convergeconverge
A deep ocean trench is A deep ocean trench is formedformed
A island chain of volcanoes is A island chain of volcanoes is formedformed
Examples would be Hawaii or Examples would be Hawaii or JapanJapan
Back to convergent boundaries
Continent-ContinentContinent-Continent Where two continental plates come togetherWhere two continental plates come together
The plates push together to form a chain of high, jagged The plates push together to form a chain of high, jagged mountainsmountains
Examples would be The HimalayasExamples would be The Himalayas
back
Transformation boundariesTransformation boundaries This occurs between two This occurs between two
plates that scrape against plates that scrape against each othereach other
At this type of boundary, a At this type of boundary, a fault is createdfault is created
A common result is an A common result is an earthquakeearthquake
A very well known example is A very well known example is the San Andreas Fault in the San Andreas Fault in CaliforniaCalifornia
Now, let’s review!Now, let’s review!
1) At a divergent plate boundary, 1) At a divergent plate boundary, how do plates move?how do plates move?
aa) Grind past each other) Grind past each other
bb) Collide with each other) Collide with each other
cc) Rift apart) Rift apart
d) Move under each otherd) Move under each other
2) Oceanic trenches are formed by:2) Oceanic trenches are formed by:
aa) Sea-floor spreading) Sea-floor spreading
bb) The collision of continents) The collision of continents
cc) The subduction of oceanic crusts into ) The subduction of oceanic crusts into the earth’s mantlethe earth’s mantle
dd) The subduction of continental crust ) The subduction of continental crust into the earth’s mantleinto the earth’s mantle
3) The supercontinent composed of 3) The supercontinent composed of all of the continents proposed by all of the continents proposed by Alfred Wegener is called:Alfred Wegener is called:
aa) Mantle) Mantle
bb) Pacific) Pacific
cc) Pangaea) Pangaea
dd) Plate tectonics) Plate tectonics
4) Where would an earthquake 4) Where would an earthquake happen?happen?
aa) At a divergent plate boundary) At a divergent plate boundary
bb) At a convergent plate boundary) At a convergent plate boundary
cc) At a transform plate boundary) At a transform plate boundary
5) 5) What is What is notnot a result of plate a result of plate tectonics?tectonics?
aa) Hurricanes) Hurricanes
bb) Volcanoes) Volcanoes
cc) Earthquakes) Earthquakes
dd) Mountains) Mountains