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Mass Wasting and Landform Development
Mass Wasting and
Landform
Development
Landslides are spectacular examples of a
common geologic process called mass wasting. Mass wasting refers to the downslope
movement of rock, regolith, and soil under
the direct influence of gravity. It is distinct
from the erosional processes that
are examined in subsequent
chapters because
mass wasting
does not
require a transporting medium such as
water, wind, or glacial ice.
The Role of Mass Wasting
Earth’ s surface is never perfectly flat but
instead consists of slopes. Some are steep
and precipitous; others are moderate or
gentle. Some are long and gradual; others
are short and abrupt. Slopes can be mantled with soil and covered by vegetation or
consist of barren rock and rubble. Taken
together, slopes are the most common
elements in our physical landscape.
In the evolution of most landforms,
mass wasting is the step that follows weathering. By itself weathering does not produce significant landforms. Rather,
landforms develop as the
products of weathering are
removed from the places where they
originate. Once weathering weakens rock
and breaks it apart, mass wasting transfers
the debris downslope, where a stream,
acting as a conveyor belt, usually carries it
away. Although there may be many intermediate stops along the way, the sediment
is eventually transported to its ultimate
destination: the sea.
The combined effects of mass wasting
and running water produce stream valleys,
which are the most common and conspicuous of Earth’ s landforms. If streams alone
were responsible for creating the valleys in
which they flow, valleys would be very
narrow features. However, the fact that
most river valleys are much wider than
they are deep is a strong indication of the
significance of mass-wasting processes in
supplying material to streams. This is
D I D Y O U K N O W ?
Although many people,
including geologists, frequently
use the word landslide, the
term has no specific definition
in geology. Rather, it is a
popular nontechnical term used
to describe all relatively rapid
forms of mass wasting.
Mass Wasting and Landform Development
Mass Wasting and
Landform
Development
Landslides are spectacular examples of a
common geologic process called mass wasting. Mass wasting refers to the downslope
movement of rock, regolith, and soil under
the direct influence of gravity. It is distinct
from the erosional processes that
are examined in subsequent
chapters because
mass wasting
does not
require a transporting medium such as
water, wind, or glacial ice.
The Role of Mass Wasting
Earth’ s surface is never perfectly flat but
instead consists of slopes. Some are steep
and precipitous; others are moderate or
gentle. Some are long and gradual; others
are short and abrupt. Slopes can be mantled with soil and covered by vegetation or
consist of barren rock and rubble. Taken
together, slopes are the most common
elements in our physical landscape.
In the evolution of most landforms,
mass wasting is the step that follows weathering. By itself weathering does not produce significant landforms. Rather,
landforms develop as the
products of weathering are
removed from the places where they
originate. Once weathering weakens rock
and breaks it apart, mass wasting transfers
the debris downslope, where a stream,
acting as a conveyor belt, usually carries it
away. Although there may be many intermediate stops along the way, the sediment
is eventually transported to its ultimate
destination: the sea.
The combined effects of mass wasting
and running water produce stream valleys,
which are the most common and conspicuous of Earth’ s landforms. If streams alone
were responsible for creating the valleys in
which they flow, valleys would be very
narrow features. However, the fact that
most river valleys are much wider than
they are deep is a strong indication of the
significance of mass-wasting processes in
supplying material to streams. This is
D I D Y O U K N O W ?
Although many people,
including geologists, frequently
use the word landslide, the
term has no specific definition
in geology. Rather, it is a
popular nontechnical term used
to describe all relatively rapid
forms of mass wasting.