Alternate freezing and thawing. Most pronounced in mountainous regions in middle latitudes. Unloading Rock bodies exposed by uplift and erosion expand. Sheeting or exfoliation - fracturing parallel to topography. Joints - vertical fractures formed by expansion, contraction during cooling or tectonic forces.
Thermal expansion Results from daily cycle of temperature change.
Most prominent in hot deserts. Biological activity Plants, burrowing animals, etc. Chemical weathering Rock chemically decomposes into materials that are stable in surface environments. The work of naturally occurring acids. HCO 3 - Dissolution Mineral attacked by polar molecules or weak acids.