What do you
already know?
SEEC Ecuador 2010
Presentation by:
Mary D. Curtis
Brittany L. Heller
What do you
want to learn?
iwith.org
• Continental Drift – theory, first advanced by Alfred Wegener, that Earth's
continents were originally one land mass. Pieces of the land mass split off and
migrated to form the continents.
• Plate Tectonics – theory that the Earth's crust and upper mantle (the
lithosphere) is broken into a number of more or less rigid, but constantly
moving, segments or plates.
• Plate boundary – The place where two or more plates in the Earth's crust
meet.
• Lithosphere – the rigid, brittle layer made up of the crust and the uppermost
part of the mantle. It is broken up into pieces called tectonic plates.
• Plates – large pieces of the lithosphere that slowly move on top of the mantle.
There are seven primary plates and many smaller ones.
• Convection – transfer of heat by movement of a fluid.
Example: (Convection currents in the mantle occur because hot rock in
the lower part of the mantle is less dense and rises, and cooler rock in the
upper part of the mantle cools, becomes more dense, and sinks. Mantle
convection is thought to be the mechanism driving the movement of
tectonic plates.)
• Divergent Plate Boundaries – where plates are moving apart and new crust is
being created. Also called Spreading Center, Rift Valley, Sea-floor spreading,
Mid-oceanic Ridge.
• Convergent Plate Boundaries – where plates are moving together
• Transform Plate Boundaries – where plates slide past one another. Example:
San Andreas Fault
• Subduction – the process by which one tectonic plate sinks below another,
returning to the mantle where the rock is re-melted. Subduction takes place at
convergent plate boundaries
• Hot spots – isolated, roughly circular plumes of melted rock (magma) that rise
from deep in the mantle (Mantle Plume) to the earth's surface
• Volcano – a vent (opening) in the Earth’s surface through which magma erupts
• Composite volcano – a steep-sided volcano built by lava flows and deposits
• Magma – melted rock below the Earth’s surface
• Lava – term used for magma once it has erupted onto the Earth's surface
• Shield Volcano – a broad volcano with repeated non-explosive eruptions of
basalt that forms a low dome or shield
• Archipelago – a group of islands
Lithosphere = The crust and part of
the upper mantle
–The crust is broken into small parts called
plates
–Plates move due to the movement of the
magma in the upper mantle
–Magma moves due to
convection (heating &
cooling of magma)
Continental Drift Theory (Alfred Wegener):
- Continents once formed supercontinent,
Pangaea, that later broke apart.
- Look at the map and
see how continents “fit.”
geology.rutgers.edu
Plate Tectonics:
- Crust is broken into many small and large plates
- Plates “float” on top of magma in upper mantle
- Magma moves due to convection
- Plates move toward, away, and next to one
another
- Plate movement causes:
- Mountains and valleys to form
- Natural hazards like earthquakes, volcanoes,
tsunamis, landslides, lahars, etc.
• Oceanic plates - denser rock composition
located below the ocean water
• Continental plates – lighter rock
composition located below the continents
• Three types of Plate Boundaries
• Divergent
• Convergent
• Transform (also called Transverse)
Divergent
Convergent
Divergent Boundaries
• Boundary between two plates
that are moving apart or rifting
• A valley forms with some
active volcanoes along center
– On land: Rift Valley
– In the Ocean: Seafloor
spreading, Mid-Oceanic
Ridges
Convergent Boundaries
• Boundaries between two plates that are
colliding (coming together)
• There are 2 types:
– Type 1: Oceanic plate to
Continental plate (subduction)
– Type 2: Same plates move towards each
other (collide)
geologytimes.com
divediscover.whoi.edu
Convergent 1: Subduction Zone
• Oceanic plate colliding with a less dense
continental plate
• Oceanic plate moves beneath the
continental plate; it melts into mantle.
• Volcanoes (mountains), trenches,
earthquakes occur at
subduction zones.
(Ex. Andes Mts.)
livescience.com
Convergent 2: Colliding Plates
(Same Composition)
• A continental (or oceanic) plate colliding with
another continental (or oceanic) plate
• Have Collision Zones: a place where folded
mountains form.
- Earthquakes, landslides
Convergence3.gif
atmos.washington.edu
Transform Fault Boundaries
• Plates slide past each other causing a rubbing
motion.
• Motion causes earthquakes
geomaps.wr.usgs.gov
sanandreas.jpg
inkycircus.com
• Continental Drift – theory, first advanced by Alfred Wegener, that Earth's
continents were originally one land mass. Pieces of the land mass split off and
migrated to form the continents.
• Plate Tectonics – theory that the Earth's crust and upper mantle (the
lithosphere) is broken into a number of more or less rigid, but constantly
moving, segments or plates.
• Plate boundary – The place where two or more plates in the Earth's crust
meet.
• Lithosphere – the rigid, brittle layer made up of the crust and the uppermost
part of the mantle. It is broken up into pieces called tectonic plates.
• Plates – large pieces of the lithosphere that slowly move on top of the mantle.
There are seven primary plates and many smaller ones.
• Convection – transfer of heat by movement of a fluid.
Example: (Convection currents in the mantle occur because hot rock in
the lower part of the mantle is less dense and rises, and cooler rock in the
upper part of the mantle cools, becomes more dense, and sinks. Mantle
convection is thought to be the mechanism driving the movement of
tectonic plates.)
• Divergent Plate Boundaries – where plates are moving apart and new crust is
being created. Also called Spreading Center, Rift Valley, Sea-floor spreading,
Mid-oceanic Ridge.
• Convergent Plate Boundaries – where plates are moving together
• Transform Plate Boundaries – where plates slide past one another. Example:
San Andreas Fault
• Subduction – the process by which one tectonic plate sinks below another,
returning to the mantle where the rock is re-melted. Subduction takes place at
convergent plate boundaries
• Hot spots – isolated, roughly circular plumes of melted rock (magma) that rise
from deep in the mantle (Mantle Plume) to the earth's surface
• Volcano – a vent (opening) in the Earth’s surface through which magma erupts
• Composite volcano – a steep-sided volcano built by lava flows and deposits
• Magma – melted rock below the Earth’s surface
• Lava – term used for magma once it has erupted onto the Earth's surface
• Shield Volcano – a broad volcano with repeated non-explosive eruptions of
basalt that forms a low dome or shield
• Archipelago – a group of islands
Ecuador:
Land of Tectonic Activity
http://facstaff.gpc.edu/~pgore/Earth&Space/GPS/platetect.html
What do you
already know?
Fact: Nine large plates and a number of smaller plates on Earth
Key Terms:http://www.trekearth.com/gallery/South_America/Ecuador/photo1150399.htm
Plate Boundaries: Convergent, Divergent, Transform
Nazca Plate is moving
away from the Cocos
Plate in a South,
southwest direction
(Divergent Plate
Boundary).
geol.umd.edu
Nazca Plate moving toward and
under the South American Plate
(Convergent Plate Boundary).
A small area of the
Nazca Plate (northwest
of the Galapagos) is
rubbing along the
Cocos Plate (Transform
Plate Boundary).
The Galapagos Islands are
formed by a Hot Spot.
facility.unavco.org
A Hot Spot is an area on a plate
where magma wells up in what
is called a Mantle Plume. When
the magma reaches the surface
in the ocean, islands are formed.
Transform
Ecuador experiences a
divergent (spreading zone)
and transform plate
boundary near the
Galapagos Islands.
Hot
Spot
oceanexplorer.noaa.gov
http://pubs.usgs.gov/gip/dynamic/world_map.html
• Create a series of islands.
• Move with the plate movement.
tulane.edu
• Islands directly over the mantle
plume have active volcanoes
(Shield Volcanoes).
• Islands erode over time and may
become sea mounts.
Shield Volcanoes relatively low, broad
volcanoes with repeated
non-explosive eruptions of
basalt that form a low
dome or shield-like shape.
cotf.edu
Northern
Western
Central
The Northern
Western
The
Central are
Galápagos
Galápagos is
Galápagos
made up of
of Wolf,
comprises
three
Isabela
and
Darwin, Pinta,
main
islands, San
Fernandina.
Marchena,
and
Cristobal,
Santa
These
are
Genovesa the
Cruz
and islands
youngest
islands. These
Floreana
and is
in
the
archipelago
islands may have
where
most
of the
with
the
most
formed from the
population
of the
active volcanoes.
hotspot
“leaking”
Galápagos lives.
northward.
bizz-101.com
The Galápagos is a group of volcanic islands (archipelago); each
of the 13 major islands is made up of at least one volcano. The
Galápagos Islands have three different geographic and geologic
regions: Northern, Central, and Western.
fuvirese.org
Geologic Formations:
• Mountain Ranges/ Volcanic Arc
• Volcanoes
• Ocean Trenches
• Valleys
A subduction zone is a
convergent plate boundary
Subduction- the process by
which one tectonic plate sinks
below another, returning to the
mantle.
pugsjones.wikispaces.com
Formed on top of a subduction zone.
(Here, the Nazca Plate is descending
under the South American Plate.)
Natural Hazards:
• Earthquakes
• Volcanoes
• Lahars/mudslides
• Tsunamis
Andes
Mountains
Stratovolcanoes
geology.com
Mantle
Mantle
peer.berkeley.edu
As the Nazca Plate melts, pressure
and friction occur resulting in the
formation of stratovolcanoes.
• 30 Volcanoes (most are
active)
• Stratovolcano (most
dangerous)
• Active volcanoes are near
population centers
• Recent eruption:
Tungurahua (2010)
whirley.wordpress.com
http://www.msnucleus.org/membership/html/jh/earth/dictionary/patedictionary.html
http://csmres.jmu.edu/geollab/Fichter/PlateTect/definitions.html
http://www.brighthub.com/education/homework-tips/articles/55610.aspx
http://www.pbs.org/wgbh/aso/tryit/tectonics/intro.html
http://facstaff.gpc.edu/~pgore/Earth&Space/GPS/platetect.html
http://geology.rutgers.edu/
https://www.cia.gov/library/publications/the-world-factbook/geos/ec.html
geol.umd.edu
oceanexplorer.noaa.gov
divediscover.whoi.edu
http://pubs.usgs.gov/gip/dynamic/world_map.html
peer.berkeley.edu
geology.com
http://facility.unavco.org/highlights/2009/galapagos.html
tulane.edu