Today I want to talk about a way in which we are able to determine how old a piece of land, or some other geologic feature is—dating techniques.
今天我想谈谈一种使我们能够确定一块土地或其他一些地质特征的年代的方法——年代测定技术。
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The Milankovitch cycle, whose records in strata can be considered both as an accurate "sediment clock" and as an auxiliary dating tool, is relatively stable in the geologic history.