Radioactive dating middle school
If there is more than one metamorphic event, and for almost every situation there would be many, the intersection of the line with the Concordia is meaningless.” I note that in the Wikipedia article that you identify, in the 0.1–1 percent range” (my emphasis) for this technique, confirming the point I made in my article that the uncertainties quoted for radiometric ages (and indeed all other quantities) are a measure of precision (or repeatability) of the .
I also note that the last sentence in the lead-in section identifies someone as “having used it [this technique] to obtain one of the earliest accurate estimates of the age of the Earth.” However, I would question how it is known that the age estimate is accurate.
Jim stated that “uranium is preferentially encased in these [zircon] crystals while lead is preferentially excluded” but did not fully explain the significance of this.
Furthermore, a recent article “Metallic lead nanospheres discovered in ancient zircons” says (in the introductory “Significance” section): “The heterogeneous distribution of Pb can, however, affect isotopic measurement by microbeam techniques, leading to spurious age estimates.” This raises significant questions for the technique and casts doubt over its robustness. Any age calculated is based on multiple unprovable assumptions to match the long-age worldview.Kevin Rogers submitted a comment to that article (reproduced below, edited to focus on substantive issues), to which Dr Jim Mason replies.Nor was there discussion about how well the experimental conditions that have been mentioned would have represented the situation within crystallizing magmas.