What On Earth
Program 22
When the Earth Moves
Segment One
Folds, Faults and Mountains
"Folds, Faults and Mountains" introduces students to the major types of deformational forces and the landforms that may result when they are present. The segment begins by describing anticlines and synclines using examples from the open folds of the Ridge and Valley Province in Virginia. Examples of small drag folds, chevron folds, flow folds and
megascopic folds in the Canadian Rockies are shown. The relationship of landforms to their underlying geologic structure is stressed through a brief look at the ridges produced by erosion of the Sinking Creek Anticline in Virginia and mountain valleys, including Massanutten Mountain in Virginia and Mount Monadnock in New Hampshire, which
were formed by erosion of recumbent anticlines. Fractures are then illustrated; and normal, reverse and strike-slip faults are defined and explained and illustrated using field examples in Virginia, Wyoming and California. The segment concludes with examples of faults which formed large features as the Grand Tetons and Sierra Nevada mountains.
