radiometrically
adverb/ˌreɪdiəʊˈmetrɪkli/
/ˌreɪdiəʊˈmetrɪkli/
- in a way that relates to a measurement of radioactivity
辐射度测量的 - These rocks have been dated radiometrically at two billion years old.
经辐射能探测，这些岩石形成于 20 亿年前。
- These rocks have been dated radiometrically at two billion years old.