Weatyering and rocks

Question 1

What is weathering?

Answer 1

decomposition and disintegration of rocks in situ

Question 2

How does climate effect weathering?

Answer 2

-peltiers diagram shows how weathering is related to moisture availability and average annual temperature
-frost shattering increases as number of freeze thaw cycles increases and chemical weather increases with moisture and heat
-Vant Hiff’s Law: rate of chemical weathering increases 2-3x for every increase in temperature of 10°C h

Question 3

How does rock type effect weathering?

Answer 3

-chemical composition
-nature of cements in sedimentary rock
-joints and bedding planes
-eg limestone consists of calcium carbonate and therefore is susceptible to carbonation-solution
-eg granite prone to hydrolysis because of feldspar present

Question 4

How does rock structure effect rate of weathering?

Answer 4

-joint patterns exert a strong control on water movement and act as lines of weakness thereby creating differential resistance within the same rock
-coarse grained rocks weather quickly owing to a large void space and high permeability whereas fine grained rocks have larger SA for weathering and highly susceptible to weathering
-rocks formed of resistant minerals like quartz and feldspar will resist. weathering compared to rocks formed of weaker minerals will weather rapidly