Zircon dating metamorphic rocks who is daniel radcliffe currently dating
The "age" or "date" is calculated from the amount of the daughter isotope produced by radioactive decay of the parent isotope.
In Grand Canyon, the "date" of metamorphism of the basalt lavas to form these Brahma amphibolites has been determined as 1690-1710 Ma (million years ago), based on U-Pb dating of minerals in the overlying Vishnu Schist and underlying Rama Schist that formed during the metamorphism.
These were originally basalt lava flows several meters to tens of meters thick.
In some outcrops pillow structures have been preserved, testimony to the basalt lavas having originally erupted and flowed under water onto the Creation Week ocean floor.
Yet the discordance patterns are consistent with past accelerated radioisotope decay, which would also render these "clocks" useless.
Thus there is no reliable evidence to dispute that these metamorphosed basalt lava flows deep in Grand Canyon date back to the Creation Week only thousands of years ago.
Most people believe that when the different radioisotope dating methods are used on the same rock unit they all yield the same age.
The best isochron plots, where all the variation from the line of best fit to the data incorporates all the analytical errors, yielded an Rb-Sr isochron age of 1240±84 Ma, an Sm-Nd isochron age of 1655±40 Ma, and a Pb-Pb isochron age of 1883±53 Ma.These included seven samples from a 150 meter long and 2 meter wide amphibolite body outcropping just upstream from the mouth of Clear Creek at river mile 84 (measured from Lees Ferry).All 27 samples were sent to two well-credentialed internationally-recognized, commercial laboratories for radioisotope analyses—potassium-argon (K-Ar) at a Canadian laboratory, and rubidium-strontium (Rb-Sr), samarium-neodymium (Sm-Nd), and lead-lead (Pb-Pb), at an Australian laboratory.Both laboratories use standard, best-practice procedures on state-of-the-art equipment.The model K-Ar ages for each of the samples ranged from 405.1±10 Ma to 2574.2±73 Ma.