Science. 1965 Dec 31;150(3705):1805-8. doi: 10.1126/science.150.3705.1805.
Calculations based on comparison of the isotopic composition of lead from iron meteorites with that of various modern terrestrial leads have placed the age of the earth at around 4550 million years. However, recent data from young volcanic rocks reveal that modern terrestrial lead can have a wide range in isotopic composition. The variations in its coinposition mean that one or more of the assumptions used in the age calculation have been violated. We modified the usual approach by comparing meteorite lead with lead from rocks 2700 million years old, from the Canadian Shield. Using this method and the same constants and assumptions utilized in the earlier calculations we calculated an age of 4750 +/- 50 million years for the earth. The earth may be approximately 200 million years older than previously thought; alternatively, primordial terrestrial lead may not have had the same isotopic composition as lead in iron meteorites does.
基于对铁陨石中铅的同位素组成与各种现代地球铅的同位素组成的比较计算，地球的年龄约为 45.5 亿年。然而，最近来自年轻火山岩的新数据表明，现代地球铅的同位素组成可能有很大的差异。其组成的变化意味着在年龄计算中使用的一个或多个假设已经被违反。我们通过将陨石铅与来自加拿大盾的 2.7 亿年岩石中的铅进行比较，修改了常用的方法。使用这种方法以及早期计算中使用的相同常数和假设，我们计算出地球的年龄为 47.50 +/- 5000 万年。地球可能比之前认为的要老大约 2 亿年；或者，原始地球铅的同位素组成可能与铁陨石中的铅不同。
