In geology, what term describes the weight of material lying above a rock unit, contributing to vertical stress?

• A. Lithostatic Pressure
• B. Overburden
• C. Hydrostatic Pressure
• D. Confined Pressure

Answer: (B)

Overburden is the weight of material lying above a rock unit, and that weight creates vertical stress on the underlying rock. You can think of it as the column of rock and soil above, often estimated from the thickness and density of the overlying layers. The resulting compression from this weight is related to lithostatic pressure, which is the pressure exerted by the surrounding rock in all directions, but the term described by the weight itself is overburden. Hydrostatic pressure comes from a fluid column, and confined pressure refers to pressure from surrounding rock in a restricted space, not specifically the weight of overlying material.