What is a record of the different layers of rock found during well drilling called?

The correct answer is a drilling log, which is a detailed record created during the drilling process that documents the various layers of rock and sediment encountered as a borehole is drilled. This information is crucial as it provides insights into the geological characteristics of the area being drilled, indicating the types of materials present, their depths, and other physical properties.

A drilling log typically includes valuable details such as the depth at which different layers were encountered, descriptions of the rock types, and any changes in drilling conditions. This record is essential for hydrologists, geologists, and engineers as it assists in assessing groundwater resources, determining the feasibility of drilling operations, and planning for future drilling activities.

While a geological log offers a more comprehensive overview of the Earth's layers in a particular location, it is a broader term that can include data not just from drilling but also from surface observations and other geological investigations. A groundwater survey refers to studies conducted to gather data about groundwater resources, and a rock profile report is often a summary or interpretation of geological findings rather than a direct record created during the drilling process itself. Therefore, the drilling log is the most accurate term for the record generated specifically during well drilling.