英语词汇“lead ratio”的英英意思、用法、释义、翻译、读音、例句、短语、词组-英语词典

lead ratio n. the ratio, in a sample of rock, of the quantity of lead (or a lead isotope) to the quantity of its radioactive parents uranium and thorium (or an appropriate isotope of one of these elements), from which the age of the sample may be determined.

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lead ratio1920

1920 Discovery Apr. 111/2 It is of course obvious that, if a mineral is altered, it has suffered chemical changes whereby the normal lead ratio is upset, for either introduction or elimination of lead may have taken place.

1920 Discovery Apr. 112/1 In some cases the lead-ratio can be used..for determining the geological position of rocks which yield their age to no other method of investigation.

1946 F. E. Zeuner Dating Past x. 325 In practice, the analyst measures the total amount of lead present, and the expression Pb^total/(U + 0·36 Th), accounting for the presence of both uranium and thorium, is the one which has to be determined in every case. It is called the ‘lead-ratio’.

单词	lead ratio
释义	> as lemmas lead ratio lead ratio n. the ratio, in a sample of rock, of the quantity of lead (or a lead isotope) to the quantity of its radioactive parents uranium and thorium (or an appropriate isotope of one of these elements), from which the age of the sample may be determined. ΘΚΠ the world > the earth > earth sciences > geology > [noun] > dating > ratio lead ratio1920 1920 Discovery Apr. 111/2 It is of course obvious that, if a mineral is altered, it has suffered chemical changes whereby the normal lead ratio is upset, for either introduction or elimination of lead may have taken place. 1920 Discovery Apr. 112/1 In some cases the lead-ratio can be used..for determining the geological position of rocks which yield their age to no other method of investigation. 1946 F. E. Zeuner Dating Past x. 325 In practice, the analyst measures the total amount of lead present, and the expression Pb^total/(U + 0·36 Th), accounting for the presence of both uranium and thorium, is the one which has to be determined in every case. It is called the ‘lead-ratio’. extracted from leadn.¹ < as lemmas
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