Microprobe dating

), which can contain very high concentrations of radiogenic Pb after only a few million of years of U and Th decay.Although uraninite is regarded as a rare accessory mineral, it is relatively abundant in leucogranitic rocks such as those found in the Himalayan orogen.With this technique, we calculate a mean chemical date that is consistent with isotope-dilution thermal ionization mass spectrometry (ID-TIMS) U-Pb dates obtained from seven other uraninite grains and a monazite crystal from the same sample.Electron microprobe chemical dating yields results that typically will be an order of magnitude less precise than conventional dates: in the specific case of the Mugu granite, single point chemical dates each have ca. However, the mean chemical date of 15 point analyses of the crystal we study has a 2SE (2 standard error) uncertainty of ca.We apply the U-Th-total Pb electron microprobe chemical dating method to a uraninite crystal from a ca.

The Ar-Ar dating technique was developed by Merrihue and Turner (1966) and proved to be an extremely powerful geochronological tool even before the advent of laser extraction techniques.Analytical procedure and age determination Analyses of monazites were carried out using the Cameca SX-100 microprobe.Acceleration voltage of 15 k V was used rather then 25 k V, because of less strong ZAF correction factors.Abstract : High spatial resolution dating of monazite by the electron-probe microanalyzer (EPMA) enables systematic and detailed studies of small minerals.Like zircon, monazite records the complex history undergone by the host rocks.

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