Weathering and Erosion
Weathering
• The breakdown do the rocks into smaller
pieces, by water, plants, ice, and wind.
Weathering
Is the process by which rocks are broken down
into smaller pieces by external conditions.
Types of Weathering
 Ice or frost wedging - temperature change
 Abrasion - friction and impact
 Plant roots and burrowing of animals
 Humans – building houses, roads, dig
tunnels, or blast into rock
Ice or Frost Wedging
Ice or frost wedging is the freezing and
thawing of water in cracks that causes
rocks to bread apart or disintegrate in
to smaller pieces.
The freezing and thawing cycle of water break the rocks into different size
pieces and they are then deposits at the base of the mountain by gravity.
Falling rocks hitting other rock is also a form of abrasion and repeated impact.
Ice or Frost Wedging
When in the water in the ground freezes it can cause sidewalks and patios to lift up.
Plant Roots
A plant’s small roots wedge themselves inside small cracks in a rock. As
the plant grows the larger roots make the crack bigger and bigger,
causing the rock to break apart.
Abrasion: Friction and Repeated Impact
Moving water can smooth and round the edges of rocks.
Living Organisms
• Lichens that grow on rocks produce weak
acids that chemically weather rock
Burrowing of animals
also help break down rock
Erosion
Is the movement of sediment
by wind, water, and glaciers and gravity.
Water Erosion
• Rivers, streams, and runoff
Water
• Water weathers rock by dissolving it
Ice
Erosion
• Glaciers
Wind Erosion
Mass Movements of land caused by ground water.
Rock is Change by
Weathering and Erosion
Weathering
Erosion
is the
process of
Breaking down
rock
Is the
process of
Moving
rock