Introduction to Plate Tectonics
California Geology 20
Lithosphere: outer layer of the earth that
includes both continental and ocean crust,
the Moho and the upper rigid portion of
the mantle. “rigid sphere”
sphere”
Asthenosphere:
Asthenosphere: A dense portion of the
mantle of unknown thickness that
supports the lithosphere and possibly
undergoes convection. “weak sphere”
sphere”
Theory: A comprehensive explanation of a
given set of data that has been repeatedly
confirmed by observation and experimentation
and has gained acceptance within the
scientific community but has not yet been
decisively proven.
Or……
..
Or……..
a wellwell-substantiated explanation of some
aspect of the natural world; an organized
system of accepted knowledge that applies in
a variety of circumstances to explain a specific
set of phenomena.
Plate Tectonics: a process of global
dynamics where the outer layers of the
earth (the lithosphere) are divided or
“broken”
broken” into several large pieces and
numerous small ones that move in
response to convection in the mantle.
Plate Tectonics: a process that accounts
for geologic activity such as earthquakes,
volcanoes and mountain building to occur
in relatively narrow zones as a result of
the interaction of lithospheric plates.
Divergent Margins
Formation of ocean Lithosphere
Deep Sea Trenches
Convergent Margins
Oceanic – Continental Convergence
Oceanic – Oceanic Convergence
Convergent
Collision
Continental – Continental Convergence
Obduction and Ophiolites
Can you name
the layers?
Transform Margins
aka Transcurrent
end