Radioactive dating rock
It is also claimed that the original basalt lavas were erupted between 17 Ma, based on U-Pb dating of "original" zircon grains in metamorphosed felsic (granitic) volcanic layers within the Brahma and Rama Schists.
Twenty-seven Brahma amphibolite samples were collected from various Inner Gorge outcrops as part of the RATE (Radioisotopes and the Age of The Earth) project.
The computer program Isoplot was used to plot isochrons and calculate isochron ages from the other radioisotope analyses.
Among these metamorphosed volcanic strata are amphibolites, belonging to the Brahma Schist.Yet the RATE research has uncovered much evidence, including the patterns of these discordances between the "dates" from the different radioisotope systems, For example, if accelerated radioisotope decay occurred, then alpha-decaying radioisotopes would yield older isochron "ages" than beta-decaying radioisotopes, which is exactly the pattern in the Brahma amphibolites (see diagram above).Because the different radioisotopes are dating the same geologic event, to have produced different "dates" has to mean that the parent radioisotopes have decayed at different rates over the same time period.Deep inside the Inner Gorge of Grand Canyon, northern Arizona, are the crystalline basement rocks that probably date back even to the Creation Week itself.Clearly visible in the canyon walls are the light-colored granites, such as the Zoroaster Granite, which are stark against the darker, folded strata of the Vishnu Schist and the other metamorphic rock units of the Granite Gorge Metamorphic Suite (see lowest purple and green shading in diagram).