Weathering and Soil Formation
Notes
Weathering
• Two types
– Mechanical Weathering
• Ice
• Abrasion
• Wind, Water, Gravity
• Plants
• Animals
Chemical Weathering
Water
Acid precipitation
Air
Weathering
• Acid Precipitation
– Precipitation is naturally acidic, but acid pre.
Contains higher levels
– High amounts can weather rocks quickly
– Can be caused by acids from natural sources like
volcanos or caused from pollution from burning
fossil fuels
– Form gases which when combined with water in
the atmosphere form weak acids that fall back to
the ground as rain or snow
Weathering
• PH scale slide
Rates of Weathering
• Differential weathering- process where less
resistant rocks are replaced with harder more
resistant rocks
• Shape-large rock will take more time to
weather, but if it is broken down by
weathering then each piece will take less time.
Rates of Weathering
• Climate- average weathering condition over a
long period of time.
• **Mailbox example pg 286
• Temperature and water can both play a big
part in weathering- water can cause ice
wedging and temperature can cause freezing
and thawing
• Elevation- steepness of mountain slopes can
increase weathering
From Bedrock to Soil
• Soil- loose mixture of small mineral fragments.