Rates of weathering The speed at which rock are broken down.This depends on several factors: Climate Rock Characterics Vegetation
CLIMATE Chemical Weathering Physical Weathering Most intense in hot and wet Particularly active in climate cold climates where Chemical reactions frost shattering promotes by high dominates temperatures Heavy rainfall provides Also active in desert necessary moisture for the climates where processes insolation weathering or exfoliation dominates E.g: Deep weathering profile and typical red soil in tropical climate reflect active oxidation
Climatic conditions 1. Strong Chemical Weathering – Hot and wet Temperature: 70C – 300C Rainfall : 1600 – 2500mm 2. Weak Chemical Weathering Temperature: -30C to -200C Rainfall : 0 – 900mm 3. Strong Physical Weathering Temperature: -50C to -100C Rainfall : 300 mm to 1300mm 4. Weak Physical Weathering Temperature: 00C to 90C Rainfall : 0 – 1700mm
Rock Characteristics Define the term joints and bedding planes. Joints – fractures or cracks that run through rocks Bedding planes – the junctions between beds of sedimentary rocks
Permeability and porosity Which of the following texture is easily weathered?
Vegetation Presence of vegetation promotes weathering Organic acids speed up hydrolysis Moss cling to rock surface, holding water against them like a wet sponge encourage chemical weathering At the same time protect a rock surface from temperature extreme which reduce physical weathering