What Is Deformation in Earth Science?

Rocks on the Earth's surface may be less ductile than those lying at deeper levels.
••• Ryan McVay/Digital Vision/Getty Images

In earth science, deformation is an alteration of the size or shape of rocks. Deformation is caused by stress, the scientific term for force applied to a certain area. Stresses on rocks can stem from various sources, such as changes in temperature or moisture, shifts in the Earth’s plates, sediment buildup or even gravity.

Types of Deformation

There are three types of rock deformation. Elastic deformation is temporary and is reversed when the source of stress is removed. Ductile deformation is irreversible, resulting in a permanent change to the shape or size of the rock that persists even when the stress stops. A fracture or rupture, also known as brittle deformation, results in the breakage of the rock. Like ductile deformation, fractures are irreversible.

Factors and Examples

Certain factors determine which type of deformation rock will exhibit when exposed to stress. These factors are rock type, strain rate, pressure and temperature. For instance, higher temperatures and pressures encourage ductile deformation. This is common deep within the Earth, where, due to higher temperatures and pressure than nearer the surface, rocks tend to be more ductile.

Related Articles

What Factors Cause Mechanical Weathering?
What Factors Affect the Melting Temperature of Rock?
How Does Weathering and Temperature Affect Rocks?
What Is Shearing in Geology?
Forms of Mechanical Weathering
The Effects of Physical Weathering
How Does Weathering Happen?
What Is Biological Weathering?
What Are the Four Causes of Mechanical Weathering?
Differences Between Foliated & Non-Foliated Metamorphic...
How Does Plate Tectonics Affect the Rock Cycle?
Density & Temperature of the Lithosphere
What Are the Three General Types of Rocks?
About Heat Weathering
Definition of Weathering of Rocks
Weathering Effects
List Four Causes of Weathering
What Are the Properties of Metamorphic Rocks?
Areas of the World That Have Sedimentary Rocks
Differences Between Extrusive and Intrusive Rocks