Figure 19. Internal isochrons of monazite from two samples (490,330 and 34-24) of Bayan Obo ores showing ages and 208Pb/204Pb initial ratios. These monazites of different ages have the most primitive nonradiogenic 208Pb/204Pb initial ratios of all Bayan Obo ores we have tested.
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Last updated 01.22.98