Nevertheless chart is instead P / D
The assertion is appropriate if the isochron story comprise number of mother ( P ) versus number of girl ( D ). i vs D / Di . Since Di will vary over different minerals, the isochron facts can plot on a line when P against D will never.
You can understand how various minerals in a rock could easily get various P / Di ratios. i has different chemical attributes. P will compliment better into some minerals than Di (and vice versa). This describes precisely why facts things don’t all fall on a single X-value.
But’s decreased easy to understand how different nutrients in a stone could find yourself with different D / Di percentages. Precisely what the isochron land can discover, in the event that result is a good fit to a line with positive slope, is the fact that there is a very powerful relationship between (1) enrichment in D , and (2) amount of P .