1. n. [Formation Evaluation]

A gamma ray log from which the uranium contribution has been subtracted. In some rocks, and in particular in carbonate rocks, the contribution from uranium can be large and erratic, and can cause the carbonate to be mistaken for a shale. The carbonate gamma ray is then a better indicator of shaliness.

Synonyms: carbonate gamma ray

See related terms: natural gamma ray spectroscopy,  potassium,  thorium