Which process occurs when pressure decreases in granite after overlying layers are removed?

Correct answer: Unloading and exfoliation

Direct answer: B, unloading and exfoliation. Granite deep underground is pressed by thick overlying rock. When erosion removes that cover, pressure on the granite decreases. The rock expands slightly, and cracks develop roughly parallel to its outer surface. Thin curved sheets can then separate or peel away; this is exfoliation, also called sheeting. A, oxidation, is a chemical reaction involving oxygen and does not explain pressure release. B is correct because it gives both the cause, unloading, and the resulting peeling, exfoliation. C, solution, is dissolution by water and is especially important in soluble rocks such as limestone. D, alluvial deposition, is the laying down of river sediment, not a granite-weathering process. Memory cue: removed load causes release, expansion and sheets peeling.