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 13 (Friday, February 15 - Monday, February 18): Folds

Brief outline of this lecture:
Simple Folds
Plunging Folds
Doubly-Plunging Folds
Domes and Basins
Complexities of Folding
     

Main points of this lecture:
Simple Folds can be categorized as anticlines and synclines.
The oldest layers are in the center of a anticline, whether it's seen in cross-section or map view.
The youngest layers are in the center of a syncline, whether it's seen in cross-section or map view.
Antlclines and synclines can plunge in one direction or in two directions.
Doubly plunging anticlines form domes; doubly-plunging synclines from basins.
Folds exist at many scales, from hand sample (or smaller) to regional.
Folding requires internal deformation of the folded layers.
One result of that deformation is fracturing when brittle layers are folded.
Another result is thinning in fold limbs and thickening in fold hinges.

Figures used in this lecture:
Simple Folds
Plunging Folds
Doubly-plunging Folds
A geologic map of Michigan
A geologic map of Tennessee, Kentucky, southern Illinois, southern Indiana, and southern Ohio
A labeled map of Domes and Basins in Tennessee, Kentucky, southern Illinois, southern Indiana, and southern Ohio
A cross-section from Tennessee to central Illinois
Problems in Folding - Part 1
Problems in Folding - Part 2 - the results

Reading assignment: None.

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