Download Plate Tectonics Part 2

Continental Drift and Plate
Tectonics (notes pt. 2)
2.55 g/cm3
4.5 g/cm3
11.05 g/cm3
x
12.95 g/cm3
x
x
Plate
Boundary
types:
Transform
Boundary - Place
where two plates
meet and slide
past each other.
Also known as a
sliding boundary.
Example: San
Andreas Fault
Plate Boundary types:
Transform Boundary Place where two plates
meet and slide past each
other. Transform
boundaries are
conservative as crust is
neither created nor
destroyed at them.
Plate Boundary
types:
Divergent
Boundary – Where
two plates are
moving away from
each other.
Examples: midocean ridges where
new sea crust
forms, rift valleys
on land.
Plate Boundary types:
Divergent boundaries
occur along spreading
centers where plates
are moving apart.
Two diverging oceanic
plates produce seafloor spreading and
new crust formation
at the boundary.
They are constructive.
Diverging oceanic plates:
Mid-Atlantic Ridge:
Diverging plates - (what type?)
Iceland:
Plate Boundary types:
Two diverging
continental
plates can
produce surface
cracking and
volcanic activity.
As the plates
stretch, cracks
appear that fill with
magma, pushing
the rift even wider.
Diverging continental plates:
East Africa:
Rift valleys:
Divergent boundaries are constructive as new crust is
created at them.
Plate Tectonics (notes pt. 3)
Plate Boundary
types:


melting
Where one plate sinks
below another it is
called a subduction
zone.
Convergent boundaries
occur where two plates are
moving toward each other.
Plate Boundary
types:
Oceanic crust subducting
under continental crust can
form continental volcanic
arcs.
The more dense oceanic
crust melts once it
descends deep enough
into the mantle.
Converging Boundaries:
Boundaries are destructive as
crust is being lost.
Ocean/Cont. Examples:
Cascades, Andes volcanoes.
Plate Boundary
types:
Oceanic crust subducting
under other oceanic crust
can form volcanic island
arcs.
The older, more dense
oceanic crust melts once it
enters the mantle.
Converging Boundaries:
Ocean / Ocean Examples:
Aleutian Islands, Mariana
Islands.


Since neither plate
sinks, they push
into one another
and mountain
forming happens.
When two
continental plates
converge, neither is
dense enough to
subduct.
Convergent
Boundaries:
Cont. / Cont.
example: Indian
plate meeting
Eurasian plate
Plate irregularities:
• Hot spot: A volcanic area that forms as a
tectonic plate moves over a point heated
from deep within the Earth's mantle.
Plate irregularities :
• Accretion: as a continental volcanic arc forms
the subducting plate has sediments and
chunks scraped off that accumulate on the
continental plate
Accretionary wedge
• Example: the west
coast of North America