index fossil
US /ˈɪn.deks ˈfɑː.səl/
UK /ˈɪn.deks ˈfɒs.əl/
名词
标准化石, 指准化石
a fossil that is useful for dating and correlating the strata in which it is found
示例:
•
Ammonites are often used as an index fossil to determine the age of rock layers.
菊石经常被用作标准化石来确定岩层的年代。
•
To be a good index fossil, a species must have been widespread and existed for a short period of time.
要成为一个好的标准化石，一个物种必须分布广泛且存在时间较短。