index fossil
US /ˈɪn.deks ˈfɑː.səl/
UK /ˈɪn.deks ˈfɒs.əl/
名詞
指標化石, 標準化石
a fossil that is useful for dating and correlating the strata in which it is found
範例:
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Ammonites are often used as an index fossil to determine the age of rock layers.
菊石經常被用作指標化石來確定岩層的年代。
•
To be a good index fossil, a species must have been widespread and existed for a short period of time.
要成為一個好的指標化石，一個物種必須分佈廣泛且存在時間較短。