WEATHERING, EROSION, AND DEPOSITION
In this lesson you will learn to identify the effects of weathering and erosion on geologic materials. You will also
learn to recognize depositional features.
TERMINAL LEARNING OBJECTIVE:
Identify the military importance of weathering and erosion of geologic materials and be able
to recognize and describe depositional features.
You will be given information on weathering, erosion, and deposition.
Demonstrate competency of the skills and knowledge involved in identifying and interpreting
the effects of weathering and erosion on geologic materials as well as recognizing and
interpreting depositional features. This will be done according to FM 5-33 and TM 5-545.
The material contained in this lesson was derived from the following publications: FM 5-33
and TM 5-545.
Geologic materials that are exposed at the earth's surface are continually subjected to atmospheric processes that
alter their physical or chemical state. This natural alteration of rock material is referred to as weathering, and the
main product of it is unconsolidated material known as soil. The loose soil particles, in turn, can be easily carried
away by water, wind, ice, or gravity. The transportation of weathered geologic material is called erosion, and the
diagnostic topographic expressions that are left behind are called erosional features. Finally, when the velocity of
the transporting medium is decreased to the point where it can no longer carry the unconsolidated material, the
eroded particles are deposited, resulting in the creation of numerous types of depositional features. An
understanding of weathering, erosion, and deposition is critical to engineers for several reasons. For example,
many engineering operations are concerned with the characteristics of weathered rock which may differ
considerably from those of their fresh counterparts. In addition, the ability to recognize erosional or depositional
features can lead to an accurate estimation of the type of materials present.