Deformation, Mountain Building, and the Continents - The Changing Earth: Exploring Geology and Evolution - page 244

OUTLINE
Introduction
Rock Deformation—How Does It Occur?
Strike and Dip—The Orientation of Deformed Rock Layers
Deformation and Geologic Structures
GEO-FOCUS: Engineering and Geology
Deformation and the Origin of Mountains
GEO-INSIGHT: Types of Faults
Earth's Continental Crust
Geo-Recap

OBJECTIVES
At the end of this chapter, you will have learned that
Rock deformation involves changes in the shape or volume or
both of rocks in response to applied forces.
Geologists use several criteria to differentiate among geologic
structures such as folds, joints, and faults.
Correctly interpreting geologic structures is important in
human endeavors such as constructing highways and dams,
choosing sites for power plants, and fi nding and extracting
some resources.
Deformation and the origin of geologic structures are impor-
tant in the origin and evolution of mountains.
Most of Earth's large mountain systems formed and, in some
cases, continue to form, at or near the three types of conver-
gent plate boundaries.
Terranes have special signifi cance in mountain building.
Earth's continental crust, and especially mountains, stands
higher than adjacent crust because of its composition and
thickness.

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The Teton Range in Wyoming is one of many mountain ranges in the Rocky
Mountains. This area has a history of mountain building that goes back at least
90 million years, but the present range began forming less than 10 million
years ago. The Teton Range formed when uplift of a block of Earth's crust took
place along fractures (faults). Now the range stands 2100 m above the valley
(Jackson Hole) to the east.

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