What is known as exfoliation? Name the processes involved in it.

When the outer layers of rocks become loose and peel off or disintegrate from the main rock, it is called exfoliation. Sudden temperature changes may cause fissures into which water penetrates which in turn stimulates chemical weathering. The sudden contraction and expansion of rocks also causes exfoliation.

The processes involved in exfoliation are mechanical or physical weathering, chemical weathering, contraction and expansion of rocks.