Geology topics

I. L. Barnes

Publications and source records attributed to I. L. Barnes.

2 recordsLinked to original sources

USGS2007

Comment on “Two New Carbonate Stable Isotope Standards”

Friedman et al (1) propose that NBS 19 calcium carbonate substitute for PDB. This is in apparent conflict with the recommendation of the September 1976 consultants’ meeting convened by the International Atomic Energy Agency on stable isotope standards. Furthermore, Friedman et al suggest ɛ‐values be adopted for NBS 19 that do not take into account the ɛ‐values of NBS 20 (Solenhofen limestone). We believe that adoption of these proposals may lead to confusion in the stable isotope literature and to lack of correspondence between historic and future isotopic results. In sharp contrast to the results of Friedman et al (1), we find NBS 20 to be a satisfactory reference material if it is handled properly. Copyright © 1982, Wiley Blackwell. All rights reserved

Geostandards Newsletter↗

USGS2002

Determination of lead, uranium, thorium, and thallium in silicate glass standard materials by isotope dilution mass spectrometry

A set of four standard glasses has been prepared which have been doped with 61 different elements at the 500-, 50-, 1-, and 0.02-ppm level. The concentrations of lead, uranium, thorium, and thallium have been determined by isotope dilution mass spectrometry at a number of points in each of the glasses. The results obtained from independent determinations in two laboratories demonstrate the homogeneity of the samples and that precision of the order of 0.5% (95% L.E.) may be obtained by the method even at the 20-ppb level for these elements. The chemical and mass spectrometric procedures necessary are presented.

Analytical Chemistry↗