Download weathering and soil formation

WEATHERING AND SOIL FORMATION
Chapter 2 Section 1
WEATHERING
 the process that breaks down rock and other substances at Earth’s
surface
EROSION
 the removal of rock particles by wind, water, ice, or gravity
MECHANICAL WEATHERING
 Rock is physically broken into smaller pieces
 Smaller pieces of rock have the same composition as the rock they
came from
CAUSES OF MECHANICAL WEATHERING
 Freezing and thawing
 Release of pressure
 Plant growth
 Actions of animals
 Abrasion – the grinding away of rock by rock particles carried by
water, ice, wind, or gravity
ICE WEDGING
 Water seeps into cracks in rock and freezes when the temperature
drops
 Water expands when it freezes
 Ice acts like a wedge that forces things apart
 Wedges of ice in rocks widen and deepen cracks
CHEMICAL WEATHERING
 process that breaks down rock through chemical changes
 causes chemical composition to change
CAUSES OF CHEMICAL WEATHERING
 Action of water
 Oxygen
 Carbon dioxide combines with water to form carbonic acid
 Living organisms
 Acid rain
PERMEABLE
 a material is full of tiny, connected air spaces that allow water to
seep through it
FACTORS THAT DETERMINE THE RATE OF WEATHERING
 Type of rock
 Human activities
 Climate
 Chemical reactions occurs more quickly where the climate is both hot
and wet