Process of block disintegration
Block disintegration isa kind of physical / mechanical weathering caused by temperature change.
In daytime, intense solar heating causes rocks to expands. At night, the temperature falls so rocks cool and contrast. Repeated expansion and contraction produce stress along joints. Joints are then widened and deepened and finally break down the rocks block by block.
Block disintegration is common over well-jointed granite in Hong Kong. It is especially significant over area with little vegetation cover because of the large diurnal range of temperature.