Final answer:
Unloading is the term used in geology to describe pressure release in rock. It happens when overlying material is removed, reducing pressure and causing the rock to expand and fracture, a process called sheeting or exfoliation.
Step-by-step explanation:
In rock, unloading is another term for pressure release. The process occurs when overlying materials are removed (often through erosion or other geological processes), which reduces the pressure on the rock below. As a result, the rock expands and fractures parallel to the surface in a process known as sheeting or exfoliation. This is a form of physical weathering that can lead to the formation of distinct rock formations and landscapes.