Why isochron data are colinear
If particular conditions that are initial met. Give consideration to some molten stone in which isotopes and elements are distributed in a fairly homogeneous manner. Its structure could be represented as a solitary point on the isochron plot:
Figure 3. Global composition regarding the melt.
While the stone cools, minerals kind. They “choose” atoms for inclusion by their chemical properties.
Since D and Di are isotopes for the element that is same they usually have identical chemical properties *. Minerals can include varying levels of that element, but all will inherit exactly the same D/Di ratio because the supply material. This leads to a y-value that is identical the information points representing each mineral (matching the Y-value for the supply product).
* Note that the aforementioned is notably simplified. You can find small differences when considering isotopes associated with same element, as well as in fairly infrequent cases you can get some quantity of differentiation among them. This can be referred to as isotope fractionation. The consequence is virtually always a very tiny departure from homogeneous circulation associated with the isotopes — possibly sufficient to introduce a mistake of 0.002 half-lives in a non-isochron age. (it may take place.