Weathering and Erosion Flashcards
weathering
the break-up of rock due to exposure to the atmosphere
erosion
removal and transport of Earth materials by natural agents (glaciers, water, winds)
mechanical weathering
rock is broken down into smaller pieces of the same material; no change in the composition
mechanical weathering ex
rock cliff- pebbles and boulders same as cliff
agents of mechanical weathering
abrasion, frost action (ice wedging), wetting and drying, plant and animal action, and exfoliation
abrasion
rocks hitting other rocks
frost action (ice wedging)
water seeps into cracks in rocks, then freezes, expands, melts, then freezes
wetting and drying
effective in breaking up rocks containing clay- clay swells up when wet and shrinks when dry- causes rocks to fall apart
plant and animal action
mosses, ants, earthworms, moles; plant roots grow into cracks- wedging rock apart; animals dig into the earth
exfoliation
peeling of rock layers due to gravity (sheetrock peels away); happens to granite
agents of chemical weathering
hydrolysis, oxidation, carbonation, and acids
hydrolysis
chemical reaction of water and minerals
oxidation
chemical reaction of oxygen and minerals (occurs in rocks with iron)
carbonation
chemical reaction of carbon dioxide (dissolved in water) and minerals- produces carbonic acid and results in mineral changing
acids
(plant decay, industrial runoff, and acid rain); acid seeps into rocks and produces cracks- rocks break apart
