Download PowerPoint Presentation - The Plate Tectonic Paradigm

Take notes
Powerpoint presentations are, by design,
not comprehensive
 Lectures and text are complementary


You are responsible for information provided
in lecture, lab, and through the text
We will discuss
solid-state
deformation
Plate Tectonic Theory
Controls on the
location and patterns of
deformation
What drives plate motion?
Ridge push - driven by elevation of midocean ridge
 Slab pull - as ocean crust grows older and
colder, it becomes progressively denser
and sinks
 Basal traction - crust pulled from below by
convecting mantle

Plate tectonic motions over time




At times in the past, plates have come together
to form large ‘supercontinents’
Land mass has at times been localized at the
equator, at times stretched to the poles,
sometimes concentrated in one hemisphere
Plate motions can be described by rotations
around poles
Rotations produce convergent, divergent, and
transcurrent motions at boundaries
Observing a structure





What does it look like?
Where is it found on the Earth, and what (if any)
are its associations with other structures or
specific rock types?
What is its 3D geometry?
What patterns do structures in this category or
tectonic environment form?
What do 3D geometry and patterns tell us about
material controls (heterogeneity, anisotropy,
relative competence) on formation?
Patterns of structures
reflect the character of
the tectonic boundary
A complete map of active
structures in this area
would include folds
What about depth?
Character of structures in a
given area depends on:
Tectonic setting
 Rock type
 Temperature, pressure, fluid content
 Strain rate
