Potassium-argon dating: Method for determining the age of igneous rocks based on the amount of argon-40 in the rock.

钾-氩年代测定法： 根据岩石内氩-40的含量来测定火成岩形成年代的方法。

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Because a radioactive form of argon is produced by decay of a naturally occurring radioactive potassium isotope, it can be used to date rocks and samples more than 100,000 years old.

因为它是稀有天然放射性同位素钾衰变而产生的，所以可以用来测定十万年以上的岩石年龄和采样。

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Using Argon-argon dating - a technique based on the decay ratio of radioactive potassium - researchers at the University of California Berkeley and the University of Glasgow have revised both the date of the dinosaur extinction 66 million years ago, and the timing of the Chicxulub asteroid impact that occurred at around the same time.

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