Affordable Access

Access to the full text

Variation of lead isotopic composition and atomic weight in terrestrial materials (IUPAC Technical Report)

Authors
  • Zhu, Xiang-Kun1
  • Benefield, Jacqueline2
  • Coplen, Tyler B.2
  • Gao, Zhaofu1
  • Holden, Norman E.3
  • 1 Chinese Academy of Geological Sciences, China , (China)
  • 2 U.S. Geological Survey, USA , (United States)
  • 3 National Nuclear Data Center, Brookhaven National Laboratory, USA , (United States)
Type
Published Article
Journal
Pure and Applied Chemistry
Publisher
Walter de Gruyter GmbH
Publication Date
Oct 01, 2020
Volume
93
Issue
1
Pages
155–166
Identifiers
DOI: 10.1515/pac-2018-0916
Source
De Gruyter
Keywords
License
Yellow

Abstract

The isotopic composition and atomic weight of lead are variable in terrestrial materials because its three heaviest stable isotopes are stable end-products of the radioactive decay of uranium (238U to 206Pb; 235U to 207Pb) and thorium (232Th to 208Pb). The lightest stable isotope, 204Pb, is primordial. These variations in isotope ratios and atomic weights provide useful information in many areas of science, including geochronology, archaeology, environmental studies, and forensic science. While elemental lead can serve as an abundant and homogeneous isotopic reference, deviations from the isotope ratios in other lead occurrences limit the accuracy with which a standard atomic weight can be given for lead. In a comprehensive review of several hundred publications and analyses of more than 8000 samples, published isotope data indicate that the lowest reported lead atomic weight of a normal terrestrial materials is 206.1462 ± 0.0028 (k = 2), determined for a growth of the phosphate mineral monazite around a garnet relic from an Archean high-grade metamorphic terrain in north-western Scotland, which contains mostly 206Pb and almost no 204Pb. The highest published lead atomic weight is 207.9351 ± 0.0005 (k = 2) for monazite from a micro-inclusion in a garnet relic, also from a high-grade metamorphic terrain in north-western Scotland, which contains almost pure radiogenic 208Pb. When expressed as an interval, the lead atomic weight is [206.14, 207.94]. It is proposed that a value of 207.2 be adopted for the single lead atomic-weight value for education, commerce, and industry, corresponding to previously published conventional atomic-weight values.

Report this publication

Statistics

Seen <100 times