This page provides a brief outline of, lists the main points of, gives links to figures for, and lists the assigned reading for a lecture in Dr. Bruce Railsback's GEOL 1121 class at the University of Georgia. This page is not intended as a set of lecture notes, and it cannot subsititute for a set of lecture notes. Familiarity with this page alone will not assure satisfactory grades on exams in the course.

Lecture 3 (January 11): Plate Tectonics II

Brief outline of this lecture:
1. Convergent plate boundaries
2. Transform plate boundaries
3. Hot spots
4. The world as plates
5. Possible driving forces for plate tectonics

Main points of this lecture:
Convergent plate boundaries can be divided into three types, oceanic-oceanic, oceanic-continental, and continental-continental.
Continental lithosphere cannot be subducted because of its lesser density than that of oceanic lithosphere and of mantle material.
Transform plate boundaries occur at offsets in the Mid-Ocean Ridges and other places where plates move past each other.
Hot spots (sources of magma from the mantle) cause chains or strings of volcanic rock where plates have passed over the hot spots.
The Earth's surface can be divided into several different named tectonic plates, of which the North American Plate is one and the Pacific Plate is the largest.
There are several possible driving mechanisms for plate tectonics, but no one of them is very convincing.

Figures used in this lecture:
New Convergent plate boundaries sketches
Transform plate boundaries sketches - sketched in class; drafted here.
A map showing ages of the Hawaiian Islands
A diagram explaining hotspots
A diagram showing an alternate model to the hotspot model
A diagram showing possible driving forces for plate tectonics

Reading assignment: Chapter 3.


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Email to Railsback (rlsbk@gly.uga.edu)
Railsback's main 1121 web page
Railsback's main web page
UGA Geology Department web page