Transcript Weathering
Weathering Physical and Chemical Weathering • The breaking down and changing of rocks Weathering • The breaking down and changing of rocks • Two types: – Mechanical Weathering • The breaking down and changing of rocks • Two types: – Mechanical – Chemical Mechanical Weathering • Physical forces break rock Mechanical Weathering • Physical forces break rock – Increases surface area Mechanical Weathering • 3 types: – Frost wedging Mechanical Weathering • 3 types: – Frost wedging – Unloading Mechanical Weathering • 3 types: – Frost wedging – Unloading – Biological activity Frost Wedging • When water freezes and thaws, it breaks rocks open Unloading • As rock is uplifted and eroded, layers of rock may peel off (exfoliation) Biological Activity • Weathering caused by living things – Examples: • Plant roots breaking rocks • Animals burrowing • Deforestation Chemical Weathering • Transformation of rock into one or more new compounds Agents of Chemical Weathering • Water absorbs gases: – Water + oxygen - causes oxides to form (oxidation) Agents of Chemical Weathering • Hydrolysis – Feldspar to Clay Agents of Chemical Weathering • Water absorbs gases: – Water + oxygen - causes oxides to form (oxidation) – Water + carbon dioxide - forms carbonic acid Agents of Chemical Weathering • Water absorbs gases: – Water + oxygen - causes oxides to form (oxidation) – Water + carbon dioxide - forms carbonic acid – Water + sulfur oxides, nitrogen oxides – acid rain Rate of Weathering • Mechanical weathering accelerates chemical weathering Rate of Weathering • Mechanical weathering accelerates chemical weathering • Also affected by: – Rock characteristics (composition) Rate of Weathering • Mechanical weathering accelerates chemical weathering • Also affected by: – Rock characteristics (composition) – Climate (strongest in hot, humid areas)