Radiometric dating problem set
I would note, however, that the efficiency of the exclusion was not mentioned (i.e.is 100% of any lead excluded from the crystal or, perhaps, less than 100%).Nor was there discussion about how well the experimental conditions that have been mentioned would have represented the situation within crystallizing magmas.Uniformitarians assume magmas crystallized slowly over millions of years under conditions of thermodynamic equilibrium.I did not discuss this technique because it seems a pretty straightforward combination of various parent-daughter relationships.The Wikipedia article that you reference would seem to confirm this.As I pointed out in the article, when the isotopic abundances are being measured very near time zero and the half-life of the radioactive parent is very long, then even a small amount of radiogenic daughter being present at time zero will result in a large erroneous ‘age’ calculation.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.
Not being a chemist, a mineralogist or a metallurgist, I have no reason to dispute this claim and, hence, did not include any further discussion.
Radioactive Dating Methods I am Kevin Rogers and am the director of Reasonable Faith Adelaide.
Last year we held a number of meetings on the young/old earth issue and gave YECs numerous opportunities to speak.
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.
It can be experimentally confirmed that molten Zircon rejects lead.
He is just a scientist who is doing his job and he doesn’t seem to have any particular axe to grind.