Lesson 10.3 PPT Flashcards
_ _ is a downslope movement of rock, regolith/unconsolidated material, and soil under the influence of gravity.
It is different from erosion because it does not need any transporting medium such as wind, water, or glacial ice.
Mass Wasting
When a stream undercuts a valley wall or when waves started to
pound on the base of a cliff,
oversteepened slopes are created.
exhibit a very high angle of
repose due to the surface
tension of water as it holds
the grain together.
Slightly wet
unconsolidated materials
If the amount of water is
too much, the angle of
repose becomes very
small and creates
fluid-like motion for the
grains.
Plants have extensive root system that holds the soil and regolith
together, thus preventing mass wasting or soil erosion.
Therefore, lack of plants may result in enhanced mass wasting
especially if large amounts of rainfall and steep slope are present in
the area.
The type of rock present in the area
may also affect the debris flow. Igneous
rocks are less prone to mass wasting than
sedimentary rocks. The presence of
joints, fractures, and bedding planes may
influence the occurrence of mass
wasting.
is the slow, downhill movement of rock or soil under the
influence of gravity.
Creep
is composed of a mixture of clay, silt, sand, and rock
fragments in which more than half of the components are more
abundant than sand.
debris flow
has a consistency of wet concrete due to its high water
content.
Mudflow
Types of Mass Wasting
contains less water and therefore less fluid than a
mudflow.
earthflow
happens when water-saturated soil moves downslope.
Solifluction
occurs when blocks of material move downhill over a
gently curved fracture in rock or regolith.
slump
bedrock
slides downslope over a fracture
plane.
rockslide,
The fastest type of mass wasting
is characterized by rapid,
free-falling rocks.
fall
