A CALCULATION OF THE ABUNDANCES OF URANIUM AND THORIUM FROM THE PRIMORDIAL PB206/PB207 RATIO
Calculation of the abundances of uranium and thorium from the primordial lead 206/lead 207 ratio
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Calculation of the abundances of uranium and thorium from the primordial lead 206/lead 207 ratio
Muonic X-ray analyses of hyperfine bismuth 209 structure, and of muonic isotope shifts in lead 206, 207, and 208
Lead in some Apollo-12 and -14 soils and breccias was volatilized under vacuum at temperature intervals of 0 to 600 C, 600 to 800 C, 800 to 1000 C, and 1000 to 1350 C. It is found that the Pb(206)/Pb(204) ratio increases and the Pb(207)/Pb(206) ratio decreases in the temperature range between 600 and 1000 C. The Pb(208)/Pb(206) ratios decrease from a value of 2 at 600 C to a value of 0.7 at 1350 C. These and other data suggest a secondary isochron age of about 4200 million years.