地学时间单位Ma和Myr及其派生单位用法的探讨

针对夏明生先生认为“Ma”及其派生单位(如“m/Ma”和“℃/Ma”)在地学期刊中属错误用法的观点,查阅了国家标准GB 3100-93和国际地学期刊有关规定。进而提出“Ma”和“Myr”均可表示“100万年”的观点,并指出这两个单位在国际期刊用法中的区别,即“Ma”用于表示某一地质事件距今的绝对年代(absolute dates),而“Myr”用于表示某一地质事件的延续时间或时间间隔(duration或interval)。另外,还提出了Ma”和“Myr”的派生单位供大家讨论。 

On time units Ma and Myr as well as their derived units in geological journals

Aiming at the point of view, held by Mr. Xia Mingsheng, that in geological journals, the time unit "Ma"and its derived units such as "m/Ma" and "℃/Ma" are illegal, we referred the stipulations about this issue by the national standard GB 3100-93 and by some foreign geological journals. Based on these stipulations, we propose that both "Ma" and "Myr" can be used to express a time length of millions of years. However, there is a certain difference between them , "Ma, Mega-annum" means millions of years ago (absolute dates) while "Myr, Millions of years" means the duration of time that a geological event lasted. Therefore, the derived units of"settlement rate or accumulation rate" and "cooling rate" can be expressed by "m/Ma" and "℃/Ma" for journals of Chinese edition and "m/Myr" and "℃/Myr" for English edition, respectively.