The correct option is 2 only
Explanation
Exfoliation is a weathering phenomenon where curved plates or shells of rock are stripped from the rock mass below. It is associated with the physical breakdown of rocks, leading to the formation of smooth and rounded surfaces.
Statement 1 is Incorrect:
In geomorphology, exfoliation is technically considered a result rather than a primary process. The actual physical processes driving it are unloading (release of confining pressure) and thermal expansion (due to temperature changes). These processes cause the rock to crack and peel, resulting in exfoliation.
Statement 2 is Correct:
Exfoliation is primarily a form of physical (mechanical) weathering. It occurs largely due to the removal of overlying rock load (unloading), which allows the rock to expand, or due to repeated heating and cooling. While chemical weathering can assist in weakening the rock, stating that it occurs solely due to chemical decomposition is factually wrong.
Statement 3 is Incorrect:
Exfoliation results in smooth and rounded surfaces, often creating large dome-shaped structures known as exfoliation domes. It does not produce sharp or angular surfaces; those are typically the result of frost wedging or block disintegration.
Key Takeaway:
Exfoliation is the detachment of curved rock shells, primarily caused by unloading and thermal expansion, resulting in smooth, rounded landforms (domes).