1. Plate Tectonics Rocks! What do you already know? What do you
want to learn?
Plate Tectonics Rocks!
SEEC Ecuador 2010
Presentation by:
Mary D. Curtis
Brittany L. Heller
iwith.org

2. Terms To Know
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.)

3. Terms To Know
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

4. 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)

5. Theory of Plate Tectonics
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

6. Theory of 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.

7. Types of Plates & Plate Boundaries
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)

8. Types of Plates & Plate Boundaries
Divergent
Convergent
Transform

9. 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

10. 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

11. 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

12. 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

13. Transform Fault Boundaries
Plates slide past each other causing a rubbing motion.
Motion causes earthquakes
sanandreas.jpg
geomaps.wr.usgs.gov
inkycircus.com

14. Plate Tectonics Example
Ecuador:
A Latin American
Plate Tectonics Example

15. Terms To Know
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.)

16. Terms To Know
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

17. Land of Tectonic Activity
Ecuador:
Land of Tectonic Activity
What do you already know?
Fact: Nine large plates and a number of smaller plates on Earth
Key Terms: Plate Boundaries: Convergent, Divergent, Transform

18. Plate Boundaries: Ecuador
Nazca Plate is moving away from the Cocos Plate in a South, southwest direction (Divergent Plate Boundary).
A small area of the Nazca Plate (northwest of the Galapagos) is rubbing along the Cocos Plate (Transform Plate Boundary).
geol.umd.edu
Nazca Plate moving toward and under the South American Plate (Convergent Plate Boundary).

19. Plate Boundaries Near Galapagos
The Galapagos
The Galapagos Islands are formed by a Hot Spot.
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.
facility.unavco.org
Plate Boundaries Near Galapagos
Transform
Ecuador experiences a divergent (spreading zone) and transform plate boundary near the Galapagos Islands.
Hot Spot
oceanexplorer.noaa.gov

20. Hot Spots Create a series of islands. Move with the plate movement.
Create a series of islands.
Move with the plate movement.
Islands directly over the mantle plume have active volcanoes (Shield Volcanoes).
Islands erode over time and may become sea mounts.
tulane.edu
Shield Volcanoes - relatively low, broad volcanoes with repeated non-explosive eruptions of basalt that form a low dome or shield-like shape.
cotf.edu

21. The Central Galápagos comprises three main islands, San Cristobal, Santa Cruz and Floreana and is where most of the population of the Galápagos lives.
The Northern Galápagos is made up of Wolf, Darwin, Pinta, Marchena, and Genovesa islands. These islands may have formed from the hotspot “leaking” northward.
The Western Galápagos are made up of Isabela and Fernandina. These are the youngest islands in the archipelago with the most active volcanoes.
Northern
Western
Central
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.

22. Subduction Zone Geologic Formations: Mountain Ranges/ Volcanic Arc
Volcanoes
Ocean Trenches
Valleys
fuvirese.org
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

23. Andes Mts. Formed on top of a subduction zone.
(Here, the Nazca Plate is descending under the South American Plate.)
Ecuador
Natural Hazards:
Earthquakes
Volcanoes
Lahars/mudslides
Tsunamis
Andes Mountains
peer.berkeley.edu
Stratovolcanoes
geology.com
As the Nazca Plate melts, pressure and friction occur resulting in the formation of stratovolcanoes.
Mantle
Mantle

24. A Country on a Subduction Zone: Ecuador
30 Volcanoes (most are active)
Stratovolcano (most dangerous)
Active volcanoes are near population centers
Recent eruption:
Tungurahua (2010)
whirley.wordpress.com

25.
geol.umd.edu
oceanexplorer.noaa.gov
divediscover.whoi.edu
peer.berkeley.edu
geology.com
tulane.edu