Abstract

The concentration of lead in 12 samples ranges from 0.58 ppm to 7.4 ppm. Eight of the samples contain less than 1 ppm of lead. Isotopic analysis of the 14 samples indicates a relatively uniform lead composition clustered about 206Pb/204Pb = 18.89, 207Pb/204Pb = 15.65, and 208Pb/204Pb = 38.50.

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