Download Lecture 11B / Plate Tectonics

Plate Tectonics
GLG 101 - Physical Geology
Bob Leighty
These notes and web links are your primary “lecture” content in this class.
Additionally, various articles are assigned each week to supplement this “lecture”
information. I believe you’ll have enough information to reference without having
to purchase a costly textbook.
These lecture notes are very similar to the ones I use in my traditional classes.
You’ll find they are loaded with imagery and streamlined text that highlight the
most essential terms and concepts. The notes provide a framework for learning
and, by themselves, are not meant to be a comprehensive source of information.
To take advantage of the global knowledge base known as the Internet, I have
included numerous hyperlinks to external web sites (like the Wikipedia, USGS,
NASA, etc.). Follow the links and scan them for relevant info. The information
from linked web sites is meant to supplement and reinforce the lecture notes –
you won’t be responsible for knowing everything contained in them.
As a distance learning student, you need to explore and understand the content
more independently than in a traditional class. As always, I will help guide you
through this learning adventure. Remember, email Dr. Bob if you have any
questions about today’s lecture ([email protected]).
Leave no questions behind!
Explore and have fun!
Plate Tectonics
Tectonic Plates
 Seismic waves tell us about the Earth's tectonic plates
Plate Tectonics
Tectonic Plates
 Tectonic plates interact
with each other at their
boundaries (and cause
earthquakes and volcanoes)
 Earthquake foci help map
geometry of tectonic plates
Plate Tectonics
Tectonic Plates
 Earth’s outer layer is divided into many strong, moving
lithospheric plates
Plate Tectonics
Tectonic Plates
 Lithosphere = Crust + rigid upper mantle
 Asthenosphere = a weaker mantle layer beneath the lithosphere
Plate Tectonics
Why Do the Plates Move?
Internal Heat & Gravity
Mantle convection
slab-pull & ridge-push
Plate Tectonics
Convergent Plate Boundaries
 Plates collide
Plate Tectonics
Convergent Plate Boundaries
Continent-Continent
 Shallow focus earthquakes
 Minimal volcanism
 Large mountain ranges
Plate Tectonics
Convergent Plate Boundaries
Continent-Continent
 Shallow focus EQs
 Little volcanism
Himalayas
Plate Tectonics
Convergent Plate Boundaries
Ocean-Continent
 Shallow to deep focus
earthquakes (subduction zone)
 Continental volcanic arc
Plate Tectonics
Convergent Plate Boundaries
Ocean-Continent
Andes
Cascades
Plate Tectonics
Convergent Plate Boundaries
Ocean-Ocean
 Shallow to deep focus
earthquakes (subduction zone)
 Island volcanic arc
Plate Tectonics
Convergent Plate Boundaries
Ocean-Ocean
Japan
Aleutians
Plate Tectonics
Divergent Plate Boundaries
 Plates move apart
Plate Tectonics
Divergent Plate Boundaries
Mid-Ocean Ridge
 Shallow focus earthquakes
 Basaltic rift volcanism
Mid-Atlantic Ridge
Plate Tectonics
Divergent Plate Boundaries
Continental Rift
East Africa Rift
Plate Tectonics
Transform Plate Boundaries
 Plates slide by each other
 Shallow-focus earthquakes
 Minimal volcanism
San Andreas Fault
Plate Tectonics
Intraplate “Hotspots”
Oceanic
 Plate moves over a mantle plume
 Shallow-focus earthquakes
 Basaltic volcanism
Hawaiian Islands - Emperor Seamounts
Plate Tectonics
Intraplate “Hotspots”
Continental
Yellowstone
Plate Tectonics
WWW Links in this Lecture
> Seismic waves - http://en.wikipedia.org/wiki/Seismic_wave
> Plate tectonics - http://en.wikipedia.org/wiki/Plate_tectonics
> Tectonic plate boundaries - http://en.wikipedia.org/wiki/Plate_tectonics#Types_of_plate_boundaries
> Lithosphere - http://en.wikipedia.org/wiki/Lithosphere
> Asthenosphere - http://en.wikipedia.org/wiki/Asthenosphere
> Mantle convection - http://en.wikipedia.org/wiki/Mantle_convection
> Driving forces of plate motion -
http://en.wikipedia.org/wiki/Plate_tectonics#Driving_forces_of_plate_motion
> Convergent plate boundary - http://en.wikipedia.org/wiki/Convergent_Plate_Boundary
> Himalayas - http://en.wikipedia.org/wiki/Himalayas
> Subduction zone - http://en.wikipedia.org/wiki/Subduction
> Volcanic arc - http://en.wikipedia.org/wiki/Volcanic_arc
> Andes - http://en.wikipedia.org/wiki/Andes
> Cascades - http://en.wikipedia.org/wiki/Cascade_Range
> Japanese Islands - http://en.wikipedia.org/wiki/Geography_of_Japan
> Aleutian Islands - http://en.wikipedia.org/wiki/Aleutian_Islands
Plate Tectonics
WWW Links in this Lecture
> Divergent boundary - http://en.wikipedia.org/wiki/Divergent_boundary
> Mid-Atlantic ridge - http://en.wikipedia.org/wiki/Mid-Atlantic_Ridge
> Continental rift - http://en.wikipedia.org/wiki/Rift_valley
> East African Rift - http://en.wikipedia.org/wiki/Great_Rift_Valley
> Transform boundary - http://en.wikipedia.org/wiki/Transform_boundary
> San Andreas fault - http://en.wikipedia.org/wiki/San_Andreas_Fault
> Hot spot - http://en.wikipedia.org/wiki/Hotspot_%28geology%29
> Mantle plume - http://en.wikipedia.org/wiki/Mantle_plume
> Yellowstone - http://en.wikipedia.org/wiki/Yellowstone_National_Park