Some triple-filament lead isotope ratio measurements and an absolute growth curve for single-stage leads

Earth and Planetary Science Letters
By: , and 

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Abstract

Triple-filament analyses of three standard lead samples are used to calibrate a mass spectrometer in an absolute sense. The bias we measure is 0.0155 percent per mass unit, and the precision (for 95% confidence limits) is ±0.13% or less for all ratios relative to204Pb. Although its precision is not quite so good as that of the lead-tetramethyl method in the analysis of large samples, the triple-filament method is less complex and is an attractive alternative for smaller sample sizes down to 500 μg.

Triple-filament data are presented for six possibly single-stage lead ores and one feldspar. These new data for ores are combined with corrected tetramethyl data for stratiform lead deposits to compute absolute parameters for a universal single-stage lead isotope growth curve. Absolute isotopic ratios for primeval lead have been determined by Oversby and because all the previous data for both meteorites and lead ores were similarly fractionated, the absolute value of238U204Pb= 9.09 ± 0.06 for stratiform leads is little different from the value 8.99 ± 0.05 originally computed by Ostic, Russell and Stanton.

Absolute values for lead isotope ratios for all interlaboratory standard samples presently available from the literature are tabulated.

Publication type Article
Publication Subtype Journal Article
Title Some triple-filament lead isotope ratio measurements and an absolute growth curve for single-stage leads
Series title Earth and Planetary Science Letters
DOI 10.1016/0012-821X(69)90154-X
Volume 6
Issue 1
Year Published 1969
Language English
Publisher Elsevier
Description 11 p.
First page 15
Last page 25
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