By T.B. Coplen, J.A. Hopple, J.K. Böhlke, H.S. Peiser, S.E. Rieder, H.R. Krouse, K.J.R. Rosman, T. Ding, R.D. Vocke, Jr., K.M. Révész, A. Lamberty, P. Taylor, and P. De Bièvre
U.S. GEOLOGICAL SURVEY
Water Resources Investigation Report 01-4222
Documented variations in the isotopic compositions of some chemical elements are responsible for expanded uncertainties in the standard atomic weights published by the Commission on Atomic Weights and Isotopic Abundances of the International Union of Pure and Applied Chemistry. This report summarizes reported variations in the isotopic compositions of 20 elements that are due to physical and chemical fractionation processes (not due to radioactive decay) and their effects on the standard atomic weight uncertainties. For 11 of those elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, silicon, sulfur, chlorine, copper, and selenium), standard atomic weight uncertainties have been assigned values that are substantially larger than analytical uncertainties because of common isotope abundance variations in materials of natural terrestrial origin. For 2 elements (chromium and thallium), recently reported isotope abundance variations potentially are large enough to result in future expansion of their atomic weight uncertainties. For 7 elements (magnesium, calcium, iron, zinc, molybdenum, palladium, and tellurium), documented isotope-abundance variations in materials of natural terrestrial origin are too small to have a significant effect on their standard atomic weight uncertainties.
This compilation indicates the extent to which the atomic weight of an element in a given material may differ from the standard atomic weight of the element. For most elements given above, data are graphically illustrated by a diagram in which the materials are specified in the ordinate and the compositional ranges are plotted along the abscissa in scales of (1) atomic weight, (2) mole fraction of a selected isotope, and (3) delta value of a selected isotope ratio.
There are no internationally distributed isotopic reference materials for the elements zinc, selenium, molybdenum, palladium, and tellurium. Preparation of such materials will help to make isotope ratio measurements among laboratories comparable.
The minimum and maximum concentrations of a selected isotope in naturally occurring terrestrial materials for selected chemical elements reviewed in this report are given below:
|
Isotope
|
Minimum mole fraction |
Maximum mole fraction |
||||
|
|
||||||
| 2H | 0 | .000 0255 | 0 | .000 1838 | ||
| 7Li | 0 | .9227 | 0 | .9278 | ||
| 11B | 0 | .7961 | 0 | .8107 | ||
| 13C | 0 | .009 629 | 0 | .011 466 | ||
| 15N | 0 | .003 462 | 0 | .004 210 | ||
| 18O | 0 | .001 875 | 0 | .002 218 | ||
| 26Mg | 0 | .1099 | 0 | .1103 | ||
| 30Si | 0 | .030 816 | 0 | .031 023 | ||
| 34S | 0 | .0398 | 0 | .0473 | ||
| 37Cl | 0 | .240 77 | 0 | .243 56 | ||
| 44Ca | 0 | .020 82 | 0 | .020 92 | ||
| 53Cr | 0 | .095 01 | 0 | .095 53 | ||
| 56Fe | 0 | .917 42 | 0 | .917 60 | ||
| 65Cu | 0 | .3066 | 0 | .3102 | ||
| 205Tl | 0 | .704 72 | 0 | .705 06 | ||
The numerical values above have uncertainties that depend upon the uncertainties of the determinations of the absolute isotope-abundance variations of reference materials of the elements. Because reference materials used for absolute isotope-abundance measurements have not been included in relative isotope abundance investigations of zinc, selenium, molybdenum, palladium, and tellurium, ranges in isotopic composition are not listed for these elements, although such ranges may be measurable with state-of-the-art mass spectrometry.
This report is available at the url: https://pubs.water.usgs.gov/wri014222.
Abstract
Introduction
Basic Concepts
Acknowledgements
Hydrogen
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Water
Silicates
Hydroxides
Organic hydrogen
Methane
Hydrogen gas
Lithium
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Marine sources
Non-marine sources
Lithium in rocks
Phosphates
Silicates
Reagents
Boron
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Marine sources
Non-marine sources
Igneous rocks
Metamorphic rocks
Sediments
Organic boron
Carbon
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Carbonate and bicarbonate
Carbon dioxide
Oxalates
Carbon monoxide
Organic carbon
Elemental carbon
Ethane
Methane
Nitrogen
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Nitrate
Nitrite
Nitrogen oxide gases
Nitrogen gas
Organic nitrogen
Nitrogen in rocks
Ammonium
Oxygen
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Oxygen gas
Water
Carbon monoxide
Carbon dioxide
Carbonates
Nitrogen oxides
Other Oxides
Phosphates
Silicates
Sulfates
Plants and animals
Magnesium
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Marine sources
Elemental magnesium
Silicon
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Igneous rocks
Metamorphic rocks
Vein quartz and silicified rocks
Sedimentary rocks
Dissolved silica
Biogenic silica
Elemental silicon
Sulfur
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Sulfates
Sulfur dioxide
Elemental sulfur
Organic sulfur
Sulfides
Chlorine
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Chlorides
Organic solvents
Calcium
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Igneous rocks
Carbonates
Plants and animals
Elemental calcium
Chromium
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Chromium (VI)
Chromium (III)
Iron (Ferrum)
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Igneous rocks
Sedimentary rocks
Non-marine sources
Plants and animals
Elemental iron
Copper (Cuprum)
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Carbonates
Chlorides
Oxides
Sulfates
Sulfides
Native copper
Archaeological copper ingots
Plants and animals
Zinc
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Selenium
Molybdenum
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Palladium
Tellurium
Thallium
Reference materials and reporting of isotope ratios
Ranges in isotopic composition
Igneous rocks
Sedimentary rocks
Reagents
Summary and Conclusions
References Cited
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