Re os dating arsenopyrite
However, even uncertainties of only 1% in the half-lives lead to very significant discrepancies in the derived radioisotope ages.
The recognition of an urgent need to improve the situation is not new (for example, Min et al. It continues to be mentioned, at one time or another, by every group active in geo- or cosmochronology (Schmitz 2012).
But many unprovable assumptions are also involved, not least being that the radioisotope systems closed at the same time and subsequently remained closed.
Furthermore, even this “gold standard” has unresolved uncertainties due to the U decay constants being imprecisely known, and to measured variations of the U ratio in terrestrial rocks and minerals and in meteorites.
From a creationist perspective, the 1997–2005 RATE (arth) project successfully made progress in documenting some of the pitfalls in the radioisotope dating methods, and especially in demonstrating that radioisotope decay rates may not have always been constant at today’s measured rates (Vardiman, Snelling, and Chaffin 2000, 2005).
Yet much research effort remains to be done to make further inroads into not only uncovering the flaws intrinsic to these long-age dating methods, but towards a thorough understanding of radioisotopes and their decay during the earth’s history within a biblical creationist framework.
We need to explore just how accurate these determinations are, whether there really is consensus on standard values for the half-lives and decay constants, and just how independent and objective the standard values are from one another between the different methods.
Of course, it is to be expected that every long-lived radioactive isotope is likely to show similar variation and uncertainty in half-life measurements because these are difficult measurements to make.
Ideally, the uncertainty of the decay constants should be negligible compared to, or at least be commensurate with, the analytical uncertainties of the mass spectrometer measurements entering the radioisotope age calculations (Begemann et al. Clearly, based on the ongoing discussion in the conventional literature this is not the case at present.
These values are based on determinations recalibrating Re-Os model ages of molybdenites by forcing them (essentially by circular reasoning) to agree with the U-Pb concordia-Pb-Pb intercept ages of zircons from the same 11 magmatic-hydrothermal systems dating from ca. It is also within the ± uncertainty range of the half-life values obtained by the best of the physical direct counting and in-growth experiments.
Yet, in spite of such experiments directly measuring Os respectively, preference has been given to the half-life value determined by forcing the Re-Os data to agree with U-Pb dates.
Ironically it is the slow decay rate of isotopes such as Rb used for deep-time dating that makes a precise measurement of that decay rate so difficult. A search for natural radioactivity in neodymium, rhenium and osmium.
Thus it could be argued that direct measurements of their decay rates should be the only acceptable experimental evidence, especially because measurements which are calibrated against other radioisotope systems are already biased by the currently accepted methodology employed by the secular community in their rock dating methods.
With the measurement technology having improved, the determinations over the last 20 years have resulted in close agreement between the four determination methods—direct physical counting and in-growth experiments, and radioisotope age comparisons using molybdenites and groups of meteorites. In Applications of radiogenic isotope systems to problems in geology, ed.