Download here

Extra Credit Option:
Attend the Public Lecture by Prof. Antonio
Lazcano on Tuesday (tomorrow) evening,
Feb 11 at 7:30 PM in Gammage Auditorium
here on campus. Write up a short summary
2-3 paragraphs for the talk, highlighting
the aspects you found most interesting.
Bring your write-up to class on Wednesday.
Be sure to write your name and ASU ID at
the top of the page.
Today’s Lecture:
 Plate margins and associated geological
pheneomena.
- Intraplate hot-spots.
- Divergent plate margins in continental settings
(origin of new ocean basins).
- Convergent margins
- Continental margin settings.
- Transform margins (ridge transforms and onland transforms.
 Brief Review
 Quiz
 Next time: Interlude A and Chapter 5!
PLATE
TECTONICS
Location of Earth’s Hot-spots
PLATE
TECTONICS
Yellowstone Hot Spot
PLATE
TECTONICS
Yellowstone Hot Spot
PLATE
TECTONICS
Types of Plate Boundaries
3 types
 divergent boundaries
 convergent boundaries
 transform fault boundaries
PLATE
TECTONICS
Continental Rifting: East Africa
Red Sea (looking southeast)
PLATE
TECTONICS
Opening of the Red Sea
PLATE
TECTONICS
Opening of the Red Sea
PLATE
TECTONICS
Formation of Triple Junctions
ocean-continent
ocean-ocean
continent-continent
3 Types of Convergent Plate Margins
Types of Continental Margins
“Active”
 Found along convergent
plate margins:
 Primarily around the
Pacific rim.
 Characterized by active
narrow continental
shelves and active
mountain building
processes (earthquakes &
volcanic activity).
 Accretionary wedges of
sediment which are
scraped off the top of a
subducting slab.
Types of Continental Margins
“Passive”
 Found within plate
interiors:
 Continental margin not
= a plate margin
Examples are
continental margins
around Atlantic.
 Broad continental
shelves consist of thick
wedges of sediment
deposited along margins
 Few earthquakes or
volcanic eruptions.
Comparison of Active and Passive
Continental Margins
PLATE
TECTONICS
Transform Plate Margins
 Transform fault boundaries
Strike-slip faults where plates slide past each other:
No production/destruction
of material
Most connect mid-ocean ridge segments
Others are “on-land”
transforms like the
San Andreas Fault.
PLATE
TECTONICS
Transform Plate Margins
On-Land Transform Faults
San Francisco Peninsula
and San Andreas Fault
In-class exercise. Name:______________________
GLG 101 Prof. Farmer ASU ID:________________
Compare the continental margin of the west coast of S. America
with the east coast of N. America.
1) South Am.
2) North Am.
Questions:
a) Active or passive continental margin?
b) Draw a cross-section (a side view)
of each area, labeling the most
important features.