Gregory Brennecka of Arizona State University and colleagues measured the relative amounts of Uranium 238 to Uranium 235 from several samples taken from the large Allende meteorite, named for the village in Mexico near where it landed in 1969.
With the more sensitive instrument, they detected small differences in isotope ratios from different inclusions within the same meteorite..
If a zircon crystal originally crystallizes from a magma and remains a closed system (no loss or gain of U or Pb) from the time of crystallization to the present, then the Discordant dates will not fall on the Concordia curve.
The differing amounts of material that were found in separate samplings of the same meteorite were unexpected.
The current standard age assigned to the solar system of 4.6 billion years was determined by studying the Uranium-to-Lead decay systems in meteorites, which are assumed to have formed before the planets did.
An event like metamorphism could heat the crystal to the point where Pb will become mobile.
Another possible scenario involves U leakage, again possibly as a result of a metamorphic event.
Though the measurements of these elements are very precise, the assumptions upon which their usefulness as a clock rests are questionable at best.
In a article on Brennecka’s findings, Gerald Wasserburg, emeritus professor of geology at Caltech, commented, “Everybody was sitting on this two-legged stool claiming it was very stable, but it turns out it’s not.” To be fair, however, it wasn’t “everybody” who claimed this.
New data collected by secular researchers has confirmed what creation scientists discovered decades ago—geologists’ assumptions about radioactive decay are not always correct.
For a century, the radioactive decay of unstable elements into more stable ones has been used as a natural clock to estimate the age of earth materials.
Thus, if we start out with 1 gram of the parent isotope, after the passage of 1 half-life there will be 0.5 gram of the parent isotope left.
After the passage of two half-lives only 0.25 gram will remain, and after 3 half lives only 0.125 will remain etc.
The energies involved are so large, and the nucleus is so small that physical conditions in the Earth (i.e. The rate of decay or rate of change of the number N of particles is proportional to the number present at any time, i.e.