Erosion
Earth’s landscape is constantly changing, as rock and
soil are worn away by the destructive effects of
water, wind, ice, and gravity. Erosion can be sudden,
such as when a landslide happens. But gradual
erosion can be just as dramatic, for example, as
rivers carve deep valleys into the Earth’s surface.
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What happens to the sediment
transported by erosion? Much of it
mixes with organic remains and
becomes soil. Rivers drop sediment
as they lose speed. In time, sediment
may become buried and harden into
new rock.Huge amounts of rock, soil,
and mud can suddenly slip
down hillsides under the effects
of gravity, tearing down trees and
burying homes. Landslides may
be caused by activities such as
tree-felling. Trees’ roots hold soil
in place, so when forests are cut
down, landslides become
more likely.LANDSLIDE!
WIND EROSION
As wind flows across the land, it
lifts up and carries countless
grains of sand and other tiny
particles. These particles, called
sediment, may be blown against
rocks at high speeds, grinding
away at their surfaces. Over many
years wind erosion has the effect
of wearing rock into new shapes
and resculpting the landscape.
Wind erosion happens most in
dry, desert regions. WIND SCULPTURES
Wind erosion wears down
soft rock faster than hard rock.
As the soft rock disappears,
strange shapes are revealed.Wind erosion will
eventually wear
away the mudstone
to the point where
the caprock falls off.The caprock at
the top of this
pillar is harder
than the
mudstone
underneath.EARTH
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(c) 2012 Dorling Kindersley. All Rights Reserved.(c) 2012 Dorling Kindersley. All Rights Reserved.