Gamma counts The radioactivity of rocks has been used for many years to help derive lithologies. Natural occurring radioactive materials (NORM) include the elements uranium, thorium, potassium, radium, and radon, along with the minerals that contain them. There is usually no fundamental connection between different rock types and measured gamma ray intensity, but there exists a strong general correlation between the radioactive isotope content and mineralogy. Logging tools have been developed to read the gamma rays emitted by these elements and interpret lithology from the information collected. https://petrowiki.org/Gamma_ray_logs Added to support Critical Zone Observatory (CZO) data use cases. ODM2 Variable Name Controlled Vocabulary ODM2 Working Group A vocabulary for describing the name of Variables.