Rocks

Explain how the characteristics of granite and limestone rocks influence weathering

Granite:
Different mineral makeup (quartz, feldspar, mica) causes different minerals to react at different rates causing stresses within the rock and eventual break up
The presence of feldspar makes hydrolysis more active and decompose the rock into residual clay.

Rock origin. Granites are formed underground and exhumed to the surface by erosion causing differential pressures and eventual cracking (presure release)

**Limestone**
Presence of calcium carbonate which reacts with water to give calcium bicarbonate which is washed away in solution
Presence of cracks and joints give way to acid water and eventual reaction. Seeds can grow between these cracks and the roots expand the rock upon growth.

Also granite is a poor conductor of heat thus weathering such as exfoliation (thermal fatigue) operates just a few inches from the surface