Download Plates converge or scrape past each other

6.4 Plates Converge or Scrape
Past Each Other
Tectonic plates push together at
convergent boundaries
At
convergent boundaries, crust is either
folded or destroyed.
If
one plate sinks beneath another, that is
called subduction.
3 types of convergent boundaries
1.Two continental plates
meet.
2.Two oceanic plates meet.
3.An oceanic plate and
a continental plate meet.
Continental-Continental Collision
 Where
two plates carrying continental crust push
together.
 Neither
plates can sink under the other because they
have the same density.
 The
edges will crumple and fold
when they collide.
 The
folded crust can be
pushed up high to form
mountains.
The Alps form as a result of the European
and African plates pushing together.
Alps
European Alps
The Himalayas
https://www.youtube.com/watch?v=dd1-Kb8ttyc
Types of Subduction
1.Oceanic-Oceanic Subduction:
2.Oceanic-Continental Subduction
1. When one plate of oceanic crust sinks, or
subducts under another plate of oceanic crust.
1. When ocean crust sinks under continental
crust.
2. Older plate sinks because it is denser than
younger plate.
2. Oceanic crust sinks because it is older and
denser than the continental crust.
3. When the older crust reaches the
asthenosphere it melts in the intense heat.
Two main features:
1. Deep ocean trenches:
deep canyons formed in
the ocean floor as the
plate sinks.
2. Island arcs:
volcanic island forms
in parallel to deep ocean
trenches.
Two main features:
1.Deep ocean trenches:
forms as the oceanic
plate sinks.
2.Costal mountains
(volcanic islands):
magma rises through
the cracks in the crust
and forming volcanoes
on the surface
Tectonic plates scrape past each
other at transform boundaries
 At
transform boundaries, crust are
neither formed nor destroyed.
 As the plates move, their edges scrape
and grind against each other.
 Transform boundaries occur mostly on:
1.Sea floor near mid-ocean ridges
2.On land seen as long cracks in Earth’s
surface.
https://www.youtube.com/watch?v=Xzpk9110Lyw
The theory of plate tectonics help
geologists today
Scientists learned:
 1.The
planet’s lithosphere has been moving for
millions of years.
 2.Earth’s
past and predicting Earth’s future as well
as the sites or future volcanoes, earthquakes,
mountain building.