Transcript Historical Geology

http://www.geophysics.rice.edu/plateboundary/
Where are the Earth’s tectonic plates and
their boundaries?
What happens at plate boundaries?
How do Earth scientists classify plate
boundaries?
Part 1.

Identify the patterns of your area of expertise
– volcanology, seismology, geography,
geochronology - AT PLATE BOUNDARIES
 Describe what you observe – do not interpret
what you see, just describe the patterns
 Wide or narrow, straight or curved, symmetric
or not symmetric, deep or shallow, ridge or
valley, active or inactive
 Identify 3-5 boundary types; color each on
your transparency; define in words
Part 2.

Bring together areas of expertise –
volcanology, seismology, geography,
geochronology

Correlate your data sets; what collective
patterns emerge?

Identify 3-5 boundary types; color each on a
master transparency; define in words
Part 3.
 Describe
the different types of boundaries
 What patterns were related in the different
data sets?
Plate Boundaries
Where Stuff Happens
Plate Tectonics
• The upper mechanical layer of Earth (lithosphere) is divided into
rigid plates that move away, toward, and along each other
• Most (!) geologic action occurs at plate boundaries in DISTINCT
patterns
Compositional
Physical / Mechanical
1. Divergent Boundaries
•Volcanic activity in fissures, some volcanos
•Shallow earthquakes, on plate boundary
•Young crust, symmetrical around boundary
•Ridge
•Rocks?
MidAtlantic
Ridge
Nazca Plate
South American Plate
Antarctic Plate
Andes Mountains
2. Convergent Boundaries
(a) Ocean-continent convergence
•Volcanos tight, parallel boundary, landward
•Shallow to deep earthquakes
•Age varies on one side of the boundary; not symmetrical
•Trench, mountain chain
•Rocks?
Andes
Mountains
Peru-Chile Trench
South
American
Plate
2. Convergent Boundaries
(b) Ocean-ocean convergence
•Volcanos tightly spaced, parallel boundary, arc
•Shallow to deep earthquakes
•Age varies on one side of the boundary; not symmetrical
•Trench, volcanic island chain
•Rocks?
Mariana Islands
Marianas Trench
Eurasian Plate
Indian Plate
Himalaya Mountains
Tibetan Plateau
Himalayan Mtns.
Mt. Everest
2. Convergent Boundaries
(c) Continent-continent convergence
•Volcanos rare, dispersed
•Shallow (to medium) dispersed earthquakes
•No age data
•High mountain chain
•Rocks?
Himalayan
Mountains
Tibetan
Plateau
Eurasian
Plate
3. Transform-Fault Boundaries
•Volcanos dispersed, most on one side
•Earthquakes complex, shallow (to medium) on both sides
•Age data not symmetrical, one side of boundary
•Complex topography, wide mountains and basins
•Rocks?
Plate Tectonics
• The upper mechanical layer of Earth (lithosphere) is divided into
rigid plates that move away, toward, and along each other
• Most (!) geologic action occurs at plate boundaries in DISTINCT
patterns
What’s Driving
Plate Tectonics
on Earth?
It’s all about convection and heat (loss)!
Vigorous convection drives plate tectonics
And for the rest of the week …
 What
features do you expect to see on
other planets if plate tectonics processes
are active?
 What does this tell you about the interior of
the planet?
 What
skills did you
use in undertaking
this activity?
 Historical
use …
 How
might you use
it in your
classroom?

What might you
modify?