WeatheringWeathering

What is Weathering?What is Weathering?• when surface processes break down when surface processes break down

rock into small pieces called rock into small pieces called sedimentsediment

Mechanical WeatheringMechanical Weathering

• physical process breakphysical process break

rocks into fragments rocks into fragments

with the same chemicalwith the same chemical

makeup as the original makeup as the original

Rock .Rock .

WIND / WATER !WIND / WATER !

• plant roots and burrowing animals plant roots and burrowing animals cause mechanical weatheringcause mechanical weathering

Ice WedgingIce Wedging• water enters cracks and freezes and water enters cracks and freezes and

expands, breaking rocks apartexpands, breaking rocks apart

• small pieces of rock have more small pieces of rock have more surface area than larger pieces of surface area than larger pieces of rock and weather fasterrock and weather faster

Chemical WeatheringChemical Weathering• chemical reactions dissolve minerals chemical reactions dissolve minerals

in rocks or change them into in rocks or change them into different mineralsdifferent minerals

• carbonic acid (formed from carbon carbonic acid (formed from carbon dioxide gas and water) and plant dioxide gas and water) and plant acids can weather rockacids can weather rock

OxidationOxidation• chemical process that occurs when chemical process that occurs when

iron is exposed to oxygen in the airiron is exposed to oxygen in the air

ClimateClimate• pattern of weather that occurs OVER pattern of weather that occurs OVER

TIMETIME

• mechanical weathering is more rapid mechanical weathering is more rapid than chemical weathering in COLD than chemical weathering in COLD climatesclimates

• chemical weathering is more rapid chemical weathering is more rapid than mechanical weathering in than mechanical weathering in WARM, WET climatesWARM, WET climates

• Rock type can affect rates of Rock type can affect rates of weatheringweathering