Radiometric dating of rock materials
Radiometric dating of rock materials - how to build a internet dating service
Zircon occurs in many colors, including reddish brown, yellow, green, blue, gray and colorless.
For instance, imaging the cathodoluminescence emission from fast electrons can be used as a prescreening tool for high-resolution secondary-ion-mass spectrometry (SIMS) to image the zonation pattern and identify regions of interest for isotope analysis.Zircon is also very resistant to heat and corrosion.Because of their uranium and thorium content, some zircons undergo metamictization.U-Pb radioisotope dating is now the absolute dating method of first choice among geochronologists, especially using the mineral zircon.A variety of analytical instruments have also now been developed using different micro-sampling techniques coupled with mass spectrometers, thus enabling wide usage of U-Pb radioisotope dating.Zircons from Jack Hills in the Narryer Gneiss Terrane, Yilgarn Craton, Western Australia, have yielded U-Pb ages up to 4.404 billion years, interpreted to be the age of crystallization, making them the oldest minerals so far dated on Earth.
In addition, the oxygen isotopic compositions of some of these zircons have been interpreted to indicate that more than 4.4 billion years ago there was already water on the surface of the Earth.Australia leads the world in zircon mining, producing 37% of the world total and accounting for 40% of world EDR (economic demonstrated resources) for the mineral.Zircon has played an important role during the evolution of radiometric dating.U decay in those rocks added daughter Pb isotopes to the common or initial Pb isotopes in them, inherited from the rock’s sources.So the Pb isotope ratios measured in these rocks today must be interpreted before their U-Pb ages can be calculated.Zircons contain trace amounts of uranium and thorium (from 10 ppm up to 1 wt%) and can be dated using several modern analytical techniques.