Transcript Plate boundaries: study information from class only

Describe the differences and
relation between the lithosphere
and asthenosphere.
Name the three types of plate
boundaries and the general
characteristic of plate movement
along each plate boundary.
What is the magnetic field and
how is it formed?
Plate Boundaries
Convergent
Divergent
Transform
Plate Tectonics

Explains the configuration of topographic
features of the Earth- mountains, valleys,
volcanoes, islands, oceanic trenches, faults
Tectonic plates



Are composed of the lithosphere
Move as a coherent mass
May contain oceanic crust and continental
crust
Direction of Movement

Perpendicular to mid-oceanic ridges
Plate Boundaries

Concentration
of stored
energy and
ultimately
release of
energy

Production
of hazards
Tectonic Map: locate plate
boundaries by symbol
Convergent Plate Boundary




Magmatic arc
Oceanic crust subducts under continental
crust
Melting occurs at about 100 miles
Hot more buoyant material rises
Volcanic Arc



Oceanic and
continental crust
Cascade Range; Andes;
Alaska
Characteristics: large
volcanoes; subduction
zone, trench, oceanic
crust subducts under
continental crust
Convergent
Plate Boundary


Map and crosssection views of the
subduction zone
The oceanic Juan de
Fuca plate subducts
under the
continental North
American Plate
Convergent Plate Boundary



Two oceanic crusts
Oceanic crust subducts under
opposing oceanic crust
Oldest oceanic crust subducts
Island Arc

Japan, Indonesia, Philippines, Caribbean,
Aleutian Islands
Convergent Plate Boundary

Earthquakes trace the
subducting slab to
about 500 miles or
650 kilometers
Gold dots represent earthquake hypocenters
Convergent Plate Boundaries



Two continental crusts
Neither subduct due to buoyancy of crusts
Mountains form


India collided
with Asia about
40 million years
ago
Mt. Everest,
29,000 feet
Divergent Plate Boundary


Two plates move apart
Run through ocean basins
Divergent Plate Boundaries
Mid-oceanic ridges, transform faults and rift
valleys, and the formation of the ocean floor
are characteristics associated with divergent
plate boundaries.
Transform Plate Boundary
Transform Plate Boundary



The tectonic plate
pass by each other
Connect other plate
boundaries
San Andreas Fault
Extension-“Pre-divergent Boundary”
Continental crust begins to stretch due to
tensional stress.
Basin and Range



Continental crust
begins to stretch due
to convection within
the asthenosphere
A series of
mountains and
valleys develop
Long Valley Caldera
is located on the
western most
portion.
East Africa Rift Zone


An area of
extension
Continental
crust is
beginning to
pull-apart
forming a rift
valley
Hot Spots


Stationary plumes of hot material that
initiate at the core/mantle interface
Hawaii: the plume is beneath oceanic crust
Hot Spots
Hot Spots

Yellowstone is associated with a hot spot
under continental crust
Plate Tectonics



The theory of plate tectonics is based on
the evaluation of scientific evidence and
observation- The Scientific Method
Continental Drift hypothesis
Seafloor Spreading hypothesis
Sketch a cross section of a
divergent plate boundary.

Label with the following terms:





rift valley;
oceanic ridge;
oceanic crust;
. volcanism;
location of melting and
and arrows indicating direction of plate
movement
Sketch a cross-section of a
convergent plate boundary that
contains an oceanic crust.

Label with the following terms:





Subduction zone
Trench
Area of melting
Area of volcanism
Arrows indicating direction of plate movement
Name the landform associated
with oceanic crust subducting
under continental crust.
Oceanic crust?