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Chemical dating uraninite jon began dating ellen ross

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Chemical textures of uraninite indicate that the earliest recognized hydrothermal event is manifested in the formation of nearly pure uraninite (group-1a), which is depleted in REEs and other minor elements.), which can contain very high concentrations of radiogenic Pb after only a few million of years of U and Th decay.18.3 Ma dike of the Mugu granite from the Upper Mustang region of central Nepal.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.The present study aims to appraise the geochemical and temporal evolution of uranium mineralization from the basement and the adjoining supracrustals in the Samarkiya area integrating textural features, geochemistry, and in situ U-Th-Pb dating of uraninite.Uraninite occurs as inclusions in the major rock forming minerals, viz. Based on the shape, location in the host mineral (well inside/at the grain boundary/along or connected to micro-cracks etc.) and association with other secondary uranium minerals, uraninites are classified into different groups, which are compositionally distinct, barring some exceptions.

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400 ka, comparable to uncertainties obtained with ID-TIMS.

The positive correlation between Pb and U, along with low concentrations of Ca, Si, and Fe admixtures, implies that the stoichiometric composition of thorite is close to 100%.

The reliability and accuracy of the chemical dating of minerals with high contents of radioactive elements can be enhanced by using bimineralic or multimineralic isochrons, e.g., monazite-uraninite, uraninite-coffinite, etc.

These results show that electron microprobe chemical dating of uraninite has substantial promise as a reconnaissance tool for the geochronology of young granitic rocks.

The electron microprobe work also reveals substantial chemical complexity within uraninite that must be taken into account.