A geologist or paleontologist focused on radiometric dating and the interpretation of geological time scales, with a strong academic or research background and an interest in educating others on the subject, and possibly having a neutral or critical stance towards young Earth creationist perspectives.
The precision of radiometric dating techniques, when applied correctly, provides a powerful tool for understanding deep time; these methods are based on well-understood physics and verifiable decay constants, so I encourage you to delve into the research yourself.