What does formation sampling help determine?

Formation sampling is a methodology used primarily in hydrology and geology to investigate subsurface conditions. It involves collecting samples of the geological material, or formation, present beneath the soil surface. This process is essential for understanding the characteristics of the underground layers, including soil composition, porosity, permeability, and the presence of various minerals or contaminants.

This information is crucial for several applications, such as groundwater studies, environmental assessments, and resource management. By analyzing the formation samples, professionals can assess how water moves through the subsurface, what materials might be influencing groundwater quality, and the potential for resource extraction in that area.

In contrast, while the exact location of groundwater sources is related to the findings of formation sampling, formation sampling itself does not directly pinpoint these sources. Similarly, vegetation and weather patterns are influenced by surface conditions rather than the geological composition evaluated through formation sampling. Therefore, determining what lies under the soil surface is the primary function of formation sampling, confirming option B as the correct answer.