Radioisotope Dating of Meteorites : IV . The Primitive and other Achondrites

Meteorites date the earth with a 4.55 ± 0.07 Ga Pb-Pb isochron called the geochron. They appear to consistently yield 4.55–4.57 Ga radioisotope ages, adding to the uniformitarians’ confidence in the radioisotope dating methods. Among the achondrites, meteorites not containing chondrules, are the primitive achondrites, angrites, aubrites, mesosiderites, and irons. Many radioisotope dating studies in the last six decades have used the K-Ar, Ar-Ar, Rb-Sr, Sm-Nd, U-Th-Pb, Lu-Hf, Re-Os, Mn-Cr, Hf-W, Al-Mg, I-Xe, and Pu-Xe methods to yield an abundance of isochron and model ages for these achondrites from whole-rock samples, and mineral and other fractions. Such age data for 10 of these achondrites were tabulated and plotted on frequency versus age histogram diagrams. They strongly cluster in many of these achondrites at 4.55–4.57 Ga, dominated by Pb-Pb, U-Pb, and Pb-Pb calibrated isochron and model ages, testimony to the Pb-Pb technique’s supremacy as the uniformitarians’ ultimate dating tool, which they consider very reliable. These ages are sometimes confirmed by Ar-Ar, Rb-Sr, Lu-Hf, Re-Os, and Sm-Nd isochron and/or model ages, but agreement could be due to calibration with the Pb-Pb system. There is also scattering of many K-Ar, Ar-Ar, Rb-Sr, Re-Os, Sm-Nd, and a few U-Pb, Pb-Pb, Th-Pb ages, in most cases likely due to thermal disturbances resulting from impact cratering of the parent asteroids. No pattern was found in these meteorites’ isochron ages similar to the systematic patterns of isochron ages found in Precambrian rock units during the RATE project, so there is no evidence of past accelerated radioisotope decay having occurred in these achondrites, and therefore on their parent asteroids. This is not as expected, yet it is the same for all meteorites so far studied. Thus it is argued that accelerated radioisotope decay must have only occurred on the earth, and only the 500–600 million years’ worth we have physical evidence for during the Flood. Otherwise, due to their 4.55–4.57 Ga “ages” these achondrites and their parent asteroids are regarded as originally representing “primordial material” that God made on Day One of the Creation Week, from which He made the non-earth portion of the solar system on Day Four, which is compatible with the Hebrew text of Genesis. Thus today’s measured radioisotope compositions of these achondrites could reflect a geochemical signature of that “primordial material,” which included atoms of all elemental isotopes. So if most of the measured daughter isotopes were already in these achondrites when they were formed on their parent asteroids, then their 4.55–4.57 Ga “ages” obtained by Pb-Pb, U-Pb, and Pb-Pb-calibrated isochron and model age dating are likely not their true real-time ages, which according to the biblical paradigm is only about 6000 real-time years. It is anticipated that further investigation of radioisotope ages data for groups of meteorites, and martian and lunar meteorites, for lunar rocks, and for rocks from every level in the earth’s geologic record, should enable these interim ideas to be confirmed or modified.