U.S. Department of the Interior U.S. Geological Survey
Compilation of Minimum and Maximum Isotope Ratios of Selected Elements in Naturally Occurring Terrestrial Materials and Reagents by T. B. Coplen', J. A. Hopple', J. K. Bohlke', H. S. Reiser', S. E. Rieder', H. R. o *< A R 1 fi Krouse , K. J. R. Rosman , T. Ding , R. D. Vocke, Jr., K. M. Revesz, A. Lamberty, P. Taylor, and P. De Bievre6
'U.S. Geological Survey, 431 National Center, Reston, Virginia 20192, USA 2The University of Calgary, Calgary, Alberta T2N 1N4, Canada 3Curtin University of Technology, Perth, Western Australia, 6001, Australia Institute of Mineral Deposits, Chinese Academy of Geological Sciences, Beijing, 100037, China National Institute of Standards and Technology, 100 Bureau Drive, Stop 8391, Gaithersburg, Maryland 20899 "institute for Reference Materials and Measurements, Commission of the European Communities Joint Research Centre, B-2440 Geel, Belgium
Water-Resources Investigations Report 01-4222
Reston, Virginia 2002 U.S. Department of the Interior GALE A. NORTON, Secretary
U.S. Geological Survey Charles G. Groat, Director
The use of trade, brand, or product names in this report is for identification purposes only and does not imply endorsement by the U.S. Government.
For additional information contact:
Chief, Isotope Fractionation Project U.S. Geological Survey Mail Stop 431 - National Center Reston, Virginia 20192
Copies of this report can be purchased from:
U.S. Geological Survey Branch of Information Services Box 25286 Denver, CO 80225-0286 CONTENTS
Abstract...... Introduction...... ^ Basic Concepts ...... 2 Aclmowledgements...... ^ Hydrogen...... ^ Reference materials and reporting of isotope ratios...... 5 Ranges in isotopic composition...... 5 Water...... Silicates...... ^ Hydroxides...... :...... ^ Organic hydrogen...... 8 Methane ...... 10 Hydrogen gas...... 10 Lithium...... ^ Reference materials and reporting of isotope ratios...... 11 Ranges in isotopic composition...... 11 Marine sources ...... 11 Non-marine sources...... 13 Lithium in rocks...... 13 Phosphates...... 13 Silicates...... _ Reagents...... J^ Boron...... Reference materials and reporting of isotope ratios...... 15 Ranges in isotopic composition...... 15 Marine sources ...... 15 Non-marine sources...... 16 Igneous rocks...... 19 Metamorphic rocks...... 19 Sediments...... ^ Organic boron...... 19 Carbon ...... 20 Reference materials and reporting of isotope ratios...... 20 Ranges in isotopic composition...... 20 Carbonate and bicarbonate ...... 20 Carbon dioxide...... 25 Oxalates...... 26 Carbon monoxide...... 26 Organic carbon ...... 26 Elemental carbon...... 28 Ethane ...... 28 Methane ...... 28 Nitrogen...... Reference materials and reporting of isotope ratios...... 29 Ranges in isotopic composition...... 29 Nitrate...... Nitrite...... Nitrogen oxide gases...... 30 Nitrogen gas ...... 30 Organic nitrogen...... 32 Nitrogen in rocks...... 34 Ammonium...... ^ Oxygen ...... Reference materials and reporting of isotope ratios...... 36 Ranges in isotopic composition...... 37 Oxygen gas...... 39 Water...... ^ Carbon monoxide...... 41 Carbon dioxide ...... 41 Carbonates ...... 41 Nitrogen oxides...... 42 Other Oxides...... 42 Phosphates ...... 42 Silicates...... Sulfates...... ^ Plants and animals...... 43 Magnesium...... ^ Reference materials and reporting of isotope ratios...... 44 Ranges in isotopic composition...... 44 Marine sources ...... 44 Elemental magnesium...... 46 SiHcon...... ^ Reference materials and reporting of isotope ratios...... 46 Ranges in isotopic composition...... 46 Igneous rocks...... 47 Metamorphic rocks...... 47 Vein quartz and silicified rocks ...... 47 Sedimentary rocks...... 48 Dissolved silica...... 49 Biogenic silica...... 50 Elemental silicon...... 50 Sulfur...... ^ Reference materials and reporting of isotope ratios...... 50 Ranges in isotopic composition...... 51 Sulfates...... ^ Sulfur dioxide...... 53 Elemental sulfur ...... 53 Organic sulfix...... ^ Sulfides ...... ^ Chlorine...... ^ Reference materials and reporting of isotope ratios...... 54 Ranges in isotopic composition...... 54 Chlorides...... 54 Organic solvents...... 56 Calcium ...... ^ Reference materials and reporting of isotope ratios...... 57 Ranges in isotopic composition...... 58 Igneous rocks...... 58 Carbonates...... 58 Plants and animals...... 59 Elemental calcium...... 60 Chromium ...... ^ Reference materials and reporting of isotope ratios...... 60 Ranges in isotopic composition...... 60 Chromium (¥!)...... Chromium (ffl)...... _^ Iron (Ferrum) ...... 6 Reference materials and reporting of isotope ratios...... 62 Ranges in isotopic composition...... 62 Igneous rocks...... 64 Sedimentary rocks...... 64 Non-marine sources...... 65 Plants and animals...... 65 Elemental iron ...... 65 Copper (Cuprum)...... _ Reference materials and reporting of isotope ratios...... 65 Ranges in isotopic composition...... 65 Carbonates ...... 65 Chlorides...... 65 Oxides...... _ Sulfates...... _ Sulfldes ...... Native copper ...... 68 Archaeological copper ingots ...... 68 Plants and animals...... 68 Zinc...... ^ Reference materials and reporting of isotope ratios...... 68 Ranges in isotopic composition...... 68 Selenium...... _ Molybdenum...... ^ Reference materials and reporting of isotope ratios...... 70 Ranges in isotopic composition...... 70 Palladium...... ^ Tellurium...... ^ Thallium ;...... Reference materials and reporting of isotope ratios...... 73 Ranges in isotopic composition...... 73 Igneous rocks...... 73 Sedimentary rocks...... 73 Reagents...... 75 Summary and conclusions ...... 75 References cited...... 76
FIGURES
1. Hydrogen isotopic composition and atomic weight of selected hydrogen-bearing materials...... 9
2. Lithium isotopic composition and atomic weight of selected lithium-bearing materials...... 14 3. Boron isotopic composition and atomic weight of selected boron-bearing materials...... 18
4. Carbon isotopic composition and atomic weight of selected carbon-bearing materials...... 24
5. Nitrogen isotopic composition and atomic weight of selected nitrogen-bearing materials...... 35
6. Oxygen isotopic composition and atomic weight of selected oxygen-bearing materials...... 40
7. Magnesium isotopic composition and atomic weight of selected magnesium-bearing materials...... 45
8. Silicon isotopic composition and atomic weight of selected silicon-bearing materials...... 49
9. Sulfur isotopic composition and atomic weight of selected sulfur-bearing materials...... 52
10. Chlorine isotopic composition and atomic weight of selected chlorine-bearing materials...... 57
11. Calcium isotopic composition and atomic weight of selected calcium-bearing materials...... 60
12. Chromium isotopic composition and atomic weight of selected chromium-bearing materials...... 62
13. Iron isotopic composition and atomic weight of selected iron-bearing materials...... 64
14. Copper isotopic composition and atomic weight of selected copper-bearing materials...... 67
15. Thallium isotopic composition and atomic weight of selected thallium-bearing materials...... 74
TABLES
1. Hydrogen isotopic composition of VSMOW reference water...... 5
2. Hydrogen isotopic composition of selected hydrogen-bearing isotopic reference materials ...... 6
3. Hydrogen isotopic composition of selected hydrogen-bearing materials...... 7
4. Lithium isotopic composition of L-SVEC lithium carbonate...... 11
5. Lithium isotopic composition of selected lithium-bearing materials...... 12 6. Boron isotopic composition of NIST SRM 951 boric acid...... 15
7. Boron isotopic composition of selected boron-bearing isotopic reference materials...... 16
8. Boron isotopic composition of selected boron-bearing materials...... 17
9. Carbon isotopic composition of a material with SnC = 0 %o relative to VPDB...... 20
10. Carbon isotopic composition of selected carbon-bearing isotopic reference materials ...... 21
11. Carbon isotopic composition of selected carbon-bearing materials...... 22
12. Isotopic composition of atmospheric nitrogen...... 30
13. Nitrogen isotopic composition of selected nitrogen-bearing isotopic reference materials ...... 31
14. Nitrogen isotopic composition of selected nitrogen-bearing materials...... 32
15. Oxygen isotopic composition of VSMOW reference water...... 36
16. Oxygen isotopic composition of selected oxygen-bearing isotopic reference materials...... 37
17. Oxygen isotopic composition of selected oxygen-bearing materials ...... 38
18. Isotopic composition of NIST SRM 980 magnesium metal...... 45
19. Magnesium isotopic composition of selected magnesium-bearing materials ...... 45
20. Silicon isotopic composition of NBS 28 silica sand...... 47
21. Silicon isotopic composition of selected silicon-bearing isotopic reference materials ...... 47
22. Silicon isotopic composition of selected silicon-bearing materials...... 48
23. Sulfur isotopic composition of a material with <534S = 0 relative to VCDT ...... 51
24. Sulfur isotopic composition of selected sulfur-bearing isotopic reference materials ...... 51
25. Chlorine isotopic composition of a material with <537C1 = 0 relative to SMOC ...... 55
26. Chlorine isotopic composition of selected chlorine-bearing isotopic reference materials ...... 55
27. Chlorine isotopic composition of selected chlorine-bearing materials...... 5 6
28. Calcium isotopic composition of NIST SRM 915a calcium carbonate...... 58 29. Calcium isotopic composition of selected calcium-bearing materials...... 59
30. Chromium isotopic composition of NIST SRM 979 chromium nitrate...... 61
31. Chromium isotopic composition of selected chromium-bearing materials...... 61
32. Isotopic composition of IRMM-014 elemental iron ...... 63
33. Iron isotopic composition of selected iron-bearing materials...... 63
34. Isotopic composition of SRM 976 elemental copper...... 66
35. Copper isotopic composition of selected copper-bearing materials...... 66
36. Isotopic composition of naturally occurring sample of zinc...... 68
37. Selenium isotopic composition of a naturally occurring material...... 69
38. Molybdenum isotopic composition of SRM 333 molybdenum ore concentrate...... 70
39. Palladium isotopic composition of a sample from Sudbury, Ontario, Canada...... 71
40. Isotope fractionation of naturally occurring palladium-bearing samples...... 72
41. Tellurium isotopic composition of a naturally occurring material...... 73
42. Isotopic composition of SRM 997 elemental thallium...... 74
43. Thallium isotopic composition of selected thallium-bearing materials...... 74
Conversion Factors
______Multiply______By______To obtain______gram (g) 0.002 204 623 pound, avoirdupois (Ib) unified atomic mass unit (u) 1,660 538 73 ± 0.000 000 13 x 10~27 kilogram (kg)
Temperature in Degrees Celsius (°C) can be converted to degrees Fahrenheit (°F) by using the following equation:
°F = (°C x 1.8)+ 32 List of Abbreviations Used in this Report
CAWIA Commission on Atomic Weights and Isotopic Abundances CDT Canon Diablo troilite PDB Peedee belemnite IAEA International Atomic Energy Agency IRMM Institute for Reference Materials and Measurements IUPAC ' International Union of Pure and Applied Chemistry MC-ICP-MS Multiple Collector Inductively Coupled Plasma Mass Spectrometry NBS National Bureau of Standards (now NIST) NIST National Institute of Standards and Technology RM Reference Material SLAP Standard Light Antarctic Precipitation SMOC Standard Mean Ocean Chloride SMOW Standard Mean Ocean Water SNIP Subcommittee on Natural Isotopic Fractionation SRM Standard Reference Material VCDT Vienna Canon Diablo troilite VPDB Vienna Peedee belemnite VSMOW Vienna Standard Mean Ocean Water < less than > greater than ~ approximately
Compilation of Minimum and Maximum Isotope Ratios of Selected Elements in Naturally Occurring Terrestrial Materials and Reagents
By T. B. Coplen, J. A. Hopple, J. K. Bohlke, H.S. Reiser, S.E. Rieder, H. R. Krouse, K. J. R. Rosman, T. Ding, R. D. Vocke, Jr., K. M. Revesz, A. Lamberty, P. Taylor, and P. De Bievre
Abstract
Documented variations in the isotopic of such materials will help to make isotope ratio compositions of some chemical elements are measurements among laboratories comparable. responsible for expanded uncertainties in the standard The minimum and maximum concentrations of a atomic weights published by the Commission on selected isotope in naturally occurring terrestrial Atomic Weights and Isotopic Abundances of the materials for selected chemical elements reviewed in International Union of Pure and Applied Chemistry. this report are given below: This report summarizes reported variations in the isotopic compositions of 20 elements that are due to Isotope Minimum Maximum physical and chemical fractionation processes (not due mole fraction mole fraction to radioactive decay) and their effects on the standard 2H 0.000 0255 0.000 1838 7Li atomic weight uncertainties. For 11 of those elements 0.9227 0.9278 (hydrogen, lithium, boron, carbon, nitrogen, oxygen, "B 0.7961 0.8107 silicon, sulfur, chlorine, copper, and selenium), 13C 0.009 629 0.011 466 standard atomic weight uncertainties have been 15N 0.003 462 0.004 210 assigned values that are substantially larger than 18Q 0.001 875 0.002 218 analytical uncertainties because of common isotope 26Mg 0.1099 0.1103 abundance variations in materials of natural terrestrial 30Si 0.030 816 0.031 023 origin. For 2 elements (chromium and thallium), 34S 0.0398 0.0473 recently reported isotope abundance variations 37C1 0.240 77 0.243 56 potentially are large enough to result in future "Ca 0.020 82 0.020 92 expansion of their atomic weight uncertainties. For 7 53Cr 0.095 01 0.095 53 elements (magnesium, calcium, iron, zinc, 56Fe 0.917 42 0.917 60 molybdenum, palladium, and tellurium), documented 65Cu 0.3066 0.3102 isotope-abundance variations in materials of natural 205j1 0.704 72 0.705 06 terrestrial origin are too small to have a significant effect on their standard atomic weight uncertainties. The numerical values above have uncertainties that This compilation indicates the extent to which depend upon the uncertainties of the determinations of the atomic weight of an element in a given material the absolute isotope-abundance variations of reference may differ from the standard atomic weight of the materials of the elements. Because reference materials element. For most elements given above, data are used for absolute isotope-abundance measurements graphically illustrated by a diagram in which the have not been included in relative isotope abundance materials are specified in the ordinate and the investigations of zinc, selenium, molybdenum, compositional ranges are plotted along the abscissa in palladium, and tellurium, ranges in isotopic scales of (1) atomic weight, (2) mole fraction of a composition are not listed for these elements, although selected isotope, and (3) delta value of a selected such ranges may be measurable with state-of-the-art isotope ratio. mass spectrometry. There are no internationally distributed isotopic This report is available at the url: reference materials for the elements zinc, selenium, http://pubs.water.usgs.gov/wri014222. molybdenum, palladium, and tellurium. Preparation Introduction Basic Concepts The atomic weight of an element in a specimen The standard atomic weights and their can be determined from knowledge of the atomic uncertainties tabulated by IUPAC are intended to masses of the isotopes of that element and the isotope represent most normal materials encountered in abundances of that element in the specimen. The terrestrial samples and laboratory chemicals. During abundance of isotope i of element E in the specimen the meeting of the Commission on Atomic Weights can be expressed as a mole fraction, *('E). For and Isotopic Abundances (CAWIA) at the General example, the mole fraction of 34S is x(*4S), which is Assembly of the International Union of Pure and «(34S)/[(«(32S) + «(33S) + «(34S) + «(36S)] or more Applied Chemistry (IUPAC) in 1985, the Working simply w(34S)/X«('S) or «(34S)/«(S), where n(E) is the Party on Natural Isotopic Fractionation [now named amount of each isotope / of element E in units of the Subcommittee on Natural Isotopic Fractionation moles. Thus, if element E is composed of isotopes 'E, (SNIP)] was formed to investigate the effects of with mole fractions x(E), the atomic weight, Ar(E), is isotope abundance variations of elements upon their the sum of the products of the atomic masses and Standard Atomic Weights and atomic-weight mole fractions of the isotopes; that is, AT(E) = uncertainties. The aims of the Subcommittee on 2X'E)vlr(E). The atomic masses from the evaluation Natural Isotopic Fractionation were (1) to identify of 1993 (Audi and Wapstra, 1993) have been used by elements for which the uncertainties of the standard CAWIA and are listed in tables herein. Isotope- atomic weights are larger than measurement abundance values that have been corrected for all uncertainties in materials of natural terrestrial origin known sources of bias within stated uncertainties are because of isotope abundance variations caused by referred to as "absolute" isotope abundances, and they fractionation processes (excluding variations caused can be determined by mass spectrometry through use by radioactivity) and (2) to provide information of synthetic mixtures of isotopes. For many elements, about the range of atomic-weight variations in the abundances of the isotopes are not invariant; thus, specific substances and chemical compounds of each these elements have a range in atomic weight. This of these elements. The purpose of this report is to report includes data for 20 such elements in their compile ranges of isotope abundance variations and natural occurrences and in laboratory reagents. corresponding atomic weights in selected materials Molecules, atoms, and ions in their natural containing 20 chemical elements (H, Li, B, C, N, O, occurrences contain isotopes in varying proportions, Mg, Si, S, Cl, Ca, Cr, Fe, Cu, Zn, Se, Mo, Pd, Te, whereby they possess slightly different physical and and Tl) from published data. Because of its focus chemical properties; thus, the physical and chemical on extreme values, this report should not be viewed properties of materials with different isotopic as a comprehensive compilation of stable isotope- compositions differ. This gives rise to partitioning of abundance variations in the literature; rather, it is isotopes (isotope fractionation) during physical or intended to illustrate ranges of variation that may be chemical processes, and these fractionations encountered in natural and anthropogenic material. commonly are proportional to differences in their The information in this report complements the bi- relevant isotope masses. Physical isotope- decadal CAWIA reviews of the atomic weights of fractionation processes include those in which the elements (Peiser and others, 1984; de Laeter and diffusion rates are mass dependent, such as others, in press), the tabulation by De Bievre and ultrafiltration or gaseous diffusion of ions or others (1984) of most precise measurements molecules. Chemical isotope-fractionation processes published on the isotopic composition of the involve redistribution of isotopes of an element among elements, and the "Isotopic Compositions of the phases, molecules, or chemical species. They either Elements 1997" by Rosman and Taylor (1998). can be (1) equilibrium isotope fractionations, when The membership of the Subcommittee on forward and backward reaction rates for individual Natural Isotopic Fractionation during the period isotope-exchange reactions are equal, or (2) kinetic 1985-2001 has consisted of T. B. Coplen isotope fractionations caused by unidirectional (chairman), J.K. Bohlke, C. A. M. Brenninkmeijer, reactions in which the forward reaction rates usually P. De Bievre, T. Ding, K. G. Heumann, N. E. are mass dependent. In equilibrium isotope reactions, Holden, H. R. Krouse, A. Lamberty, H. S. Peiser, G. in general, the heavy isotope will be enriched in the I. Ramendik, E. Roth, M. Stievenard, L. Turpin, and compound with the higher oxidation state and R. D. Vocke, Jr., with additional assistance from M. commonly in the more condensed state. Thus, for Shima. example, 13C is enriched in carbon dioxide relative to graphite, and in graphite relative to methane, and 2H liquid water at 15 °C by 1.02 percent relative to its is enriched in liquid water relative to water vapor. In concentration in water vapor. kinetic processes, statistical mechanics predicts that Variations in stable isotope abundance ratios the lighter (lower atomic mass) of two isotopes of an typically are small. Stable isotope ratios commonly element will form the weaker and more easily broken are expressed as relative isotope ratios in S'E bond. The lighter isotope is more reactive; therefore, notation (pronounced delta) according to the relation it is concentrated in reaction products, enriching reactants in the heavier isotope. Examples of reactions that produce kinetic isotope fractionation include many biological reactions, treatment of limestone with acid to liberate carbon dioxide, and the rapid freezing of water to ice. Sulfate reduction by where S'E refers to the delta value of isotope number bacteria in respiration is an example of a biologically i of element E of sample X relative to the reference mediated kinetic isotope-fractionation process. ref, and «x('E)/«xfE) and nK^E)/nK^E) are the ratios Kinetic isotope fractionations of biological processes of the isotope amounts in unknown X and a reference are variable in magnitude and may be in the direction ref. A positive S'E value indicates that the unknown opposite to that of equilibrium isotope fractionations is more enriched in the heavy isotope than is the for the same chemical species. reference. A negative S'E value indicates that the Isotopic equilibrium between two phases does not unknown is depleted in the heavy isotope relative to mean that the two phases have identical mole fractions the reference. In the literature, S'E values of isotope of each isotope (isotope abundances), only that the ratios have been reported in parts per hundred (% or ratios of these mole fractions always are constant. per cent), parts per thousand (%o or per mill), and Water vapor in a closed container in contact with other units. In this report, S'E values are given in per liquid water at a constant temperature is an example mill; thus, the expression above can be written of two phases in oxygen and hydrogen isotopic equilibrium; in this case, the concentrations of the heavy isotopes ( 0 H and 1RO) are higher in the liquid
Table 1. Hydrogen isotopic composition of VSMOW reference water
[Atomic mass given in unified atomic mass units, u]
Isotope Atomic Mass Mole Fraction 'H 1.007 825 0319(6) 0.99984426(5) 2H 2.014 101 7779(6) 0.000 155 74(5) From Audi and Wapstra (1993). From Rosman and Taylor (1998) and Hagemann and others (1970). Table 2. Hydrogen isotopic composition of selected hydrogen-bearing isotopic reference materials
[Values for S2H given in per mill relative to VSMOW on a scale normalized such that the <52H of SLAP is -428 %o relative to VSMOW]
Reference Material Substance Reference VSMOW water 0 (exactly) Gonfiantini, 1978 GISP water -189.73 ±0.87 Gonfiantini and others, 1995 SLAP water -428 (exactly) Gonfiantini, 1978 NBS22 oil -120 ± 4 Hut, 1987 NBS30 biotite -65.7 ± 0.27 Gonfiantini and others, 1995 NGS1 CEU in natural gas -138 ± 6 Hut, 1987 NGS2 CHU in natural gas -173 ± 4 Hut, 1987 NGS2 C2He in natural gas -121 ±7 Hut, 1987 NGS3 CKU in natural gas -176 ± 10 Hut, 1987 IAEA-CH-7 (PEF1) polyethylene -100.33 ± 2.05 Gonfiantini and others, 1995 isotope-fractionation factor between water and H2S is typically are depleted in 2H. The most positive <52H greater than 2, giving rise to water with a 82H value value for fruit juice and wine (+47 %o) was reported of +375 %o. Experimentally, it is possible to produce for a sample of red wine (Martin and others, 1988). S2H values in excess of+130 %o by evaporating water Silicates The range of S2U values of silicates with a fan in a low humidity environment. (table 3) is from -429 %o (Wenner, 1979) to +5 %0 Most salt hydrates are depleted in 2H relative to (Graham and Sheppard, 1980). Hydrogen isotope the coexisting liquid for example, by 15 %o for fractionations between most hydrogen-bearing gypsum. Some hydrates concentrate 2H; CaCl2-6H2O minerals and water appear to be largely a function of and Na2SO4.10H2O are enriched in 2H by 10 %o and the mass to charge ratio of the octahedral cation, and 17 %o, respectively (Friedman and OTSTeil, 1977; most hydrogen-bearing silicates are depleted in 2H by Friedman and CWeil, 1978). 0 %o to 100 %o. Because local meteoric water is Agricultural food products are influenced by the involved in the formation or alteration of most isotopic composition of local meteoric waters. The hydrogen-bearing silicates, these silicates show a wide f\ >y enrichment of apple juice in 2H is not as large as that range in 5 H. The extremely low value of 6 H in in orange juice because of the lower levels of pectolites [-429 %o to -281 %0; (Wenner, 1979)] is evapotranspiration occurring in the cooler northern not completely understood, but must result because of latitudes of apple production. However, citrus trees an unusual isotope-fractionation factor (Wenner, are found in areas with subtropical climates when 1979). Analcime channel waters vary systematically evaporation fractionates the water isotopes, resulting with sample locality, whereas channel water in other in 2H enrichment in cellular water. For example, the zeolites (chabazite, clinoptilolite, laumontite, and 2H content of orange juice is enriched by up to 40 %o mordenite) is largely from the ambient water vapor relative to local meteoric water. Bricout and others where the zeolites were last stored (Karlsson and (1973; also see Dormer and others, 1987) showed that Clayton, 1990). Hydrated silica (opal and diatomite) natural orange juice could be distinguished from contains several types of structural water, much of orange juice reconstituted from concentrate and water which will be exchanged if temperatures reach 100 °C added from higher latitudes because such waters or at lower temperatures over geologic time. Table 3. Hydrogen isotopic composition of selected hydrogen-bearing materials
[Values for S2H given in per mill relative to VSMOW on a scale normalized such that the (52H of SLAP is -428 %o relative to VSMOW]
Minimum d H Value Maximum d H Value Substance <52H Reference Reference WATER Sea water (deep) -2.5 Redfield and +3.2 Redfield and Friedman, Friedman, 1965 1965 Other (naturally occurring) -495 Jouzel and others, +129 Fontes and Gonfiantini, 1987 1967 Fruit juice and wine -43 Bricout and others, +47 Martin and others, 1988 1973 SILICATES Ca2NaH(SiO3) (pectolite) -429 Wenner, 1979 -281 Wenner, 1979 Other -208 Friedman and +5 Graham and Sheppard, OTSfeil, 1978 1980 HYDROXIDES Aluminum and iron -220 Yapp, 1993 -8 Bernard, 1978; Bird and others, 1989 ORGANIC HYDROGEN Non-marine organisms -237 Schutze and others, +66 Sternberg and others, 1982 1984 Marine organisms -166 Schiegl and Vogel, -13 Schiegl and Vogel, 1970 1970 Organic sediments -103 Schiegl, 1972 -59 Oremland and others, 1988a Coal -162 Smith and -65 Redding, 1978 Pallasser, 1996 Crude oil -163 Schiegl and Vogel, -80 Schiegl and Vogel, 1970 1970 Ethanol (naturally -272 Rauschenbach and -200 Rauschenbach and occurring) others, 1979 others, 1979 Ethanol (synthetic) -140 Rauschenbach and -117 Rauschenbach and others, 1979 others, 1979 Table 3. Hydrogen isotopic composition of selected hydrogen-bearing materials Continued
Minimum 6 H Value Maximum 6 H Value <52H Substance
Hydroxides The J2H of naturally occurring plants using the CAM photosynthetic pathway (<52H = gibbsite (A12O3-3H2O) and goethite [FeO(OH)] range +51 ± 10 %o) from those using Cs and C4 pathways from -220 %o to -8 %o (Yapp, 1993; Bernard, 1978) (<52H = -40 ± 20 %o) according to Sternberg and as shown in table 3. Hydroxides formed during much others (1984). Zhang and others (1994) investigated of the Phanerozoic in systems such as lateritic the site-specific natural isotope fractionation of paleosols, bog ores, and other materials. Stable hydrogen in glucose and find that <52H values of hydrogen and oxygen isotope ratios of hydroxides in glucose from Cs plants are more negative (-106 these systems may provide information on continental ± 65 %0) than those in C4 plants (-22 ± 65 %o); the paleoclimates (Yapp, 1993; Bird and others, 1989). uncertainty in the difference between the <52H values Organic hydrogen The hydrogen isotopic they report as ±16 %o. An example of the practical composition of organisms primarily reflects the use of this difference is to identify adulteration of hydrogen isotopic composition of water in the local orange juice with beet sugar (Dormer and others, environmental. Trees acquire their 2H/1H ratios from 1987). The organism with the lowest 2H content precipitation or (and) ground water. The large range found in the literature is algae from Lake Pomornika, in <52H of meteoric water gives rise to the large Antarctica, with a <52H value of-237 %o (Schiitze and f\ variation in 6 H of vegetation (Yapp and Epstein, others, 1982). The cellulose of Yucca torreyi has the 1982) shown in table 3. The <52H values of sap from highest 2H content found in the literature (<52H = different types of trees range from -66 %o to -1 %o +66 %0; Sternberg and others, 1984). Marine (White and others, 1985) with an anomalous value of organisms show a smaller range in <52H value of +60 %o for sap from a poplar tree (Schiegl and Vogel, between -166 %o and -13 %o (Schiegl and Vogel, 1970). Evaporation and species-specific variations 1970). The <52H values of organic sediments range during metabolic or biochemical processes affect the between -103 %o (Schiegl, 1972) and -59 %o hydrogen isotopic composition of organisms (Oremland and others, 1988a). The variation of 52H (Sternberg, 1988). The hydrogen isotopic in coals thought to be attributable to differing composition of cellulose can be used to distinguish origins, maturation histories, moisture content during Atomic Weight 1.00785 1.00790 1.00795 1.00800
Mole Fraction of 2 H 0.00000 0.00004 0.00008 0.00012 0.00016 I STANDARD ATOMIC WEIGHT ^
WATER Sea water (deep) SLAP GISP Other (naturally occurring) VSMOW Fruit juice and wine
SILICATES Ca2NaH(SiO3) (pectolite) NBS30 Other
HYDROXIDES Aluminum and iron
ORGANIC HYDROGEN Non-marine organisms Marine organisms Organic sediments Coal Crude oil NBS22 Ethanol (naturally occurring) Ethanol (synthetic)
METHANE Atmospheric Other (naturally occurring) NGS3 HYDROGEN GAS Air Other (naturally occurring) Commercial tank gas Auto exhaust & industrial contamination
-1000 -800 -600 -400 -200 200 62 H, in %0 relative to VSMOW
Figure 1. Hydrogen isotopic composition and atomic weight of selected hydrogen-bearing materials. The d H scale and 2H mole-fraction scale fy were matched using the data in table 1;i* therefore, the uncertainty in placement of the atomic-weight scale and the H mole-fraction scale relative to the 6 H scale is equivalent to ±0.3 %o. growth, and plant type ranges from -162 %o (Smith used in food and beverage authentication. and Pallasser, 1996) to -65 %o (Redding,; 1978). Rauschenbach and others (1979) note that ethanol Crude oil deuterium distributions (table 3): range in produced from naturally occurring materials has a <52H
10 The lowest reported 2H concentration in a also have been reported in the literature. naturally occurring terrestrial material is from IRMM-015 and IRMM-016 lithium carbonates hydrogen gas with a
Table 4. Lithium isotopic composition of L-SVEC lithium carbonate
[Atomic mass given in unified atomic mass units, u]
Isotope Atomic Mass Mole Fraction 6Li 6.015 1223(5) 0.075 91(20) 7Li 7.016 0041(5) 0.924 09(20) A From Audi and Wapstra (1993). B From Rosman and Taylor (1998) and Qi and others (1997a).
11 Table 5. Lithium isotopic composition of selected lithium-bearing materials
[Values for S7Li given in per mill relative to L-SVEC]
Minimum <57Li Value Maximum <57Li Value Substance Reference S7U Reference MARINE SOURCES Sea water +32.4 You and Chan, 1996 +33.9 Chan and Edmond, 1988 Hydrothermal fluids +2.6 Chan and others, 1994 +11 Chan and others, 1993 Foraminifera and -10 Hoefs and Sywall, 1997 +42 Hoefs and Sywall, 1997 carbonate sediments Brines and pore +1 Vocke and others, 1990 +56.3 You and Chan, 1996 water NON-MARINE SOURCES Surface water +15.5 Chan and others, 1992 +34.4 Chan and Edmond, 1988 Ground and thermal -19 T. Bullen, U.S. Geological +10 T. Bullen, U.S. Geological water Survey, written Survey, written communication, 2001 communication, 2001 Contaminated +10 T. Bullen, U.S. Geological +354 T. Bullen, U.S. Geological ground water Survey, written Survey, written communication, 2001 communication, 2001 LITHIUM IN ROCKS Basalt (unaltered) +3.4 Chan and others, 1992 +6.8 Chan and others, 1992 Basalt (altered) -2.1 Chan and others, 1992 +13.5 Chan and others, 1995 Rhyolite -3.5 Bullen and Kharaka, 1992 -3.5 Bullen and Kharaka, 1992 Granite 0.0 R. D. Vocke, Jr., +11.2 Tomascak and others, 1995 unpublished data Limestone -3.5 Bullen and Kharaka, 1992 +33.5 Hoefs and Sywall, 1997 PHOSPHATES LiAlFPO4 -13 Cameron, 1955 +7.4 Svec and Anderson, 1965 (amblygonite) SILICATES LiAl(SiO3)2 -12.6 Cameron, 1955 +11.8 R. D. Vocke, Jr., (spodumene) unpublished data KLiAl2Si3Oio -6.6 Cameron, 1955 +7.2 Cameron, 1955 (lepidolite)
12 Table 5. Lithium isotopic composition of selected lithium-bearing materials Continued
Minimum <57Li Value Maximum <57Li Value Substance S7U Reference Reference REAGENTS 6Li depleted +434 Qi and others, 1997a +3 013 Qi, and others, 1997a compounds Other -11 Qi and others, 1997a +23 Qi, and others, 1997a
= +56.3 %o (You and Chan, 1996). The mole fraction marine sediments (Bullen and Kharaka, 1992). The of 7Li in this specimen is 0.9278 and AJLi) = 6.9438. lowest 13 Atomic Weight 6.938 6.939 6.940 6.941 6.942 6.943 6.944 Mole Fraction of Li 0.923 0.924 0.925 0.926 0.927 0.928 STANDARD ATOMIC WEIGHT MARINE SOURCES Sea water Hydrothermal fluids Foraminifera and carbonate sediments Brines and pore water NON-MARINE SOURCES Surface water Ground and thermal water Contaminated ground water to +354 LITHIUM IN ROCKS Basalt (unaltered) Basalt (altered) Rhyolite Granite Limestone PHOSPHATES LiAIFPO4 (amblygonite) SILICATES LiAI(SiO3)2 (spodumene) KLiAI2Si3O10 (lepidolite) REAGENTS 6Li depleted compounds +434 to+3013 L-SVEC IRMM-016 Other -20 -10 0 10 20 30 40 50 60 87Li, in %o relative to L-SVEC Figure 2. Lithium isotopic composition and atomic weight of selected lithium-bearing materials. The S7Li scale and 7Li mole-fraction scale were matched using the data in table 4; therefore, the uncertainty in placement of the atomic-weight scale and the 7Li mole-fraction scale relative to the <57Li scale is equivalent to ±3 %o. Anderson, 1965). large amounts of lithium have been isotopically Silicates Li-bearing silicates were among the fractionated by removal of 6Li for use in hydrogen first Li-bearing specimens to be analyzed for lithium bombs. The remaining lithium is substantially isotopic composition. The S7Li of spodumene ranges enriched in 7Li and some of this lithium has found its between -12.6 %o (Cameron, 1955) and +11.8 %o (R. way into laboratory reagents and into the D. Vocke, Jr., unpublished data). That of lepidolite environment. An analysis of 39 laboratory reagents ranges between -6.6 %o and +7.2 %o (Cameron, 1955). (Qi and others, 1997b) indicated a (57Li range of Reagents Of the chemical elements discussed in between -11 %o (for Baker-Adamson lithium sulfate) this report, lithium is particularly unusual because and +3013 %o (for Fisher Scientific lithium 14 hydroxide). The <57Li of lithium carbonate, the most water and 5 rock reference materials to boron isotope common starting material for other Li-bearing laboratories (Tonarini and others, in press). These reagents, ranged from 0 %o to +12 %o. materials have been analyzed by negative ion thermal ionization mass spectrometry, positive ion thermal ionization mass spectrometry, inductively coupled Boron A(B) = 10.811(7) plasma mass spectrometry, and MC-ICP-MS. These materials are listed in table 7 and shown in fig 3. Boron is not abundant its average concentration in crustal rocks (9 mg/kg) is less than that of lithium Ranges in Isotopic Composition (18 mg/kg). A primary commercial source is borate Boron isotope ratios show large variations minerals found in commercial quantities in California (> 90 %o) in the terrestrial environment (table 8 and (USA) and Turkey. 10B is used in nuclear figure 3). Naturally occurring boron predominantly is applications in neutron shields and control rods found in the +3 oxidation state and does not undergo because of the high absorption cross-section of 10B for redox reactions. In solution, boric acid is enriched in thermal neutrons. The primary non-nuclear uses of HB by 20 %o relative to coexisting borate ions, boron are in heat resistant glasses (Pyrex), detergents, B(OH)4~. During precipitation, borate preferentially soaps, cleaners, cosmetics, porcelain enamels, enters the solid phase, enriching the residual solution synthetic herbicides and fertilizers, and abrasives. in UB. When boron is attracted to clays or other active surfaces, the predominant species attracted is Reference materials and reporting of isotope tetrahedral B(OH)4~; thus, residual dissolved boron is ratios enriched in HB. Bassett (1990) has compiled and The primary reference for the relative abundance critically evaluated boron isotopic measurements prior measurements of boron isotopes is the NIST reference to 1990. material SRM 951 boric acid, which is assigned a Marine sources The SnB of sea water is <5nB value of 0 %0. Boron isotope ratio measurements relatively constant at +39.5 %o. The values of sea commonly are performed using negative ion thermal water measured by Schwarcz and others (1969) have ionization mass spectrometry, and isotope ratios not been used because they probably are too high commonly are determined with a 1-a standard according to Bassett (1990). Shima's (1962; 1963) deviation of ±1 %o. analyses of borax and ocean water differ by more than The absolute isotope abundances of SRM 951 30 %o from those of other researchers; thus, they are have been measured by Catanzaro and others (1970) not included in this report. As sea water evaporates, and are listed in table 6. A second reference material, salts are depleted in UB by 30 per mill in the early IRMM-011 boric acid, is nearly identical in isotopic stages of precipitation and by 20 per mill in the latter composition to SRM 951 (NIST, 1999a), and it is stages of precipitation (Vengosh and others, 1992), available from IRMM (Institute for Reference increasing the UB content of evaporated sea water. Materials and Measurements), Geel, Belgium. Two The highest published SUB value of evaporated sea boric acid reference materials (IRMM-610 and SRM water is +58.5 %o from the Mediterranean Sea 952) are depleted in HB (NIST, 1999b; IRMM, 2001). (Klotzli, 1992). The IAEA recognized the paucity of boron isotopic Large-scale boron exchange between sea water reference materials and has recently distributed 3 and oceanic crust occurs at both high and low Table 6. Boron isotopic composition of NIST SRM 951 boric acid [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 lOg 10.012 9371(3) 0.198 27(13) "B 11.0093055(4) 0.801 73(13) From Audi and Wapstra (1993). From Rosman and Taylor (1998) and Catanzaro and others (1970) 15 Table 7. Boron isotopic composition of selected boron-bearing isotopic reference materials [Values for <5HB given in per mill relative to NIST SRM 951 boric acid] Reference Substance Reference Material SRM 951 boric acid IRMM-011 boric acid -0.16 Lamberty and De Bievre, 1991 SRM 952 boric acid -987 NIST, 1999b IRMM-610 boric acid solution -987 IRMM, 2001 IAEA-B-1 surface sea water, Western Mediterranean +37.7 ± 2.1 Tonarini and others, in press Sea IAEA-B-2 ground water, alluvial aquifer, Cecina +13.6 ± 2.6 Tonarini and others, in press River, lower basin (Tuscany, Italy) IAEA-B-3 ground water, alluvial aquifer, River -21.3 ± 0.9 Tonarini and others, in press Cecina, upper basin (Tuscany, Italy) IAEA-B-4 tourmaline, Elba Island (Tuscan -10.6 ±3.2 Tonarini and others, in press Archipelago, Italy) IAEA-B-5 basalt, Mt. Etna's main crater (Sicily), -4.2 ± 2.7 Tonarini and others, in press eruption July 1998 IAEA-B-6 obsidian, Lipari Island, Italy (Eolian -3.3 ± 1.8 Tonarini and others, in press Archipelago) IAEA-B-7 Miocene marine limestone (Abruzzi, +7.2 ± 3.9 Tonarini and others, in press Italy) IAEA-B-8 Pliocene clay (Montelupo Fiorentino, -5.4 ± 1.2 Tonarini and others, in press Italy) temperature (Spivack and Edmond, 1987). <5UB of modern marine carbonates falls in a relatively Hydrothermal solutions from 9 separate oceanic vent narrow range (+22 ± 3 %o) according to Hemming fields have <$HB values between +30.0 %o and and Hanson (1992). This band is about 20 %o more +36.8 %o (Spivack and Edmond, 1987). Boron negative than that of sea water and is explained by the extracted from basalts involved in high temperature fact that tetrahedral B(OH)~4, which is depleted in HB reaction show no resolvable isotope fractionation. by 20 %o relative to B(OH)3, is preferentially Serpentinites and basalts altered at low temperature incorporated into the carbonate structure. The range are enriched in boron and have <5UB values between in SUB value expands from +4.0 %o to +32.2 %0 +0.1 %o and +9.2 %o. This preferential transfer of 10B (Vengosh and others, 1991b) if hand picked into altered oceanic sediments is in part responsible foraminifera and ostracoda are included. for the high <5UB of sea water. Non-marine sources The primary sources of Because the SUB of sea water is about +40 %o boron are non-marine evaporite deposits in California and because the isotope fractionation between B(OH)s (USA) and Turkey, which yield large quantities of and B(OH)~4 is about 20 %o (Kakihana and others, borates. It was hypothesized that non-marine borates 1977), the SnB of marine evaporites should be about would reflect the isotopic composition of crustal rocks +20 %o or higher. Swihart and others (1986) find the and minerals, which is about 40 %o more negative range to be between +18.2 %o and +31.7 %o. The than marine boron (Swihart and others, 1986). Except 16 Table 8. Boron isotopic composition of selected boron-bearing materials [Values for <5* 'B given in per mill relative to NIST SRM 951 boric acid] Minimum SnE Value Maximum <5nB Value Substance <5nB Reference SllE Reference MARINE SOURCES Sea water +38.4 Vengosh and +40.4 Nomura and others, 199 la others, 1982 Evaporated sea water +36.5 Vengosh and +58.5 Klotzli, 1992 others, 199 la Hydrothermal fluids +30.0 Spivack and +36.8 Spivack and Edmond, 1987 Edmond, 1987 Evaporite minerals +18.2 Swihart and +31.7 Swihart and others, 1986 others, 1986 Carbonates (Skeletal parts +4.0 Vengosh and +32.2 Vengosh and and formations) others, 1991b others, 1991b NON-MARINE SOURCES Rain water +0.8 Spivack, 1986 +35 Spivack, 1986 Brines, surface and -21.3 Tonarini and +59.2 Vengosh and ground waters others, in press others, 199 la Hydrothermal fluids -9.3 Palmer and +29.1 Klotzli, 1992 Sturchio, 1990 Evaporite minerals -31.3 Finley and +7.3 Agyei and others, 1962 McMullen, 1968 IGNEOUS ROCKS -17.0 Trumbull and -1.7 Spivack and Chaussidon, Edmond, 1987 1999 METAMORPHIC ROCKS -34.2 Wang and Xiao, +22 Swihart and 2000 Moore, 1989 SEDIMENTS -17 Ishikawa and +26.2 Ishikawa and Nakamura, 1993 Nakamura, 1993 ORGANIC BORON -12 Wieser and +29.3 Vanderpool and others, 2001 Johnson, 1992 for one value at +24 %o, the SnB of non-marine The boron isotopic composition of fumarolic evaporites ranged between -31.3 %o (Finley and condensates is thought to reflect the boron isotopic others, 1962) and +7.3 %o (Agyei and McMullen, composition of associated magmas (Kanzaki and 1968). Thus, non-marine borates are depleted in UB others, 1979). Nomura and others (1982) measured relative to marine borates (+18.2 %o to +31.7 %o) and 40 fumarolic condensates from the Japanese island boron isotope ratios can be used to differentiate the arc. Most condensates possess <5UB values near two evaporite borates (Swihart and others, 1986). +6 %o, reflecting the boron isotopic composition of 17 Atomic Weight 10.805 10.810 10.815 10.820 Mole Fraction of 11 B 0.795 0.800 0.805 0.810 STANDARD ATOMIC WEIGHT MARINE SOURCES IAEA-B-1 Sea water Evaporated sea water Hydrothermal fluids Evaporite minerals Carbonates (skeletal parts and formations) IAEA-B-7 NON-MARINE SOURCES Rain water IAEA-B-3 IAEA-B-2 Brines, surface and ground waters Hydrothermal fluids Evaporite minerals IRMM-0111 SRM951 IAEA-B-4 IAEA-B-5 IGNEOUS ROCKS IAEA-B-6 METAMORPHIC ROCKS IAEA-B-8 | SEDIMENTS ORGANIC BORON -40 -20 0 20 40 60 511 B, in %0 relative to SRM 951 Figure 3. Boron isotopic composition and atomic weight of selected boron-bearing materials. The SUB scale and UB mole-fraction scale were matched using the data in table 6; therefore, the uncertainty in the placement of the atomic-weight scale and the UB mole-fraction scale relative to the 6UB scale is equivalent to ±0.8 %o. crustal rocks. However, values above +17 %o were obtained for Sasso Pisano 6 is not included because it found in the southernmost end of the northeastern cannot be satisfactorily explained (Klotzli, 1992) it Japanese arc, and these more positive values were may be due to matrix effects during the isotopic attributed to interaction of magmas with sea water analysis. (SUB = +39.5 %o). In a reconnaissance of An important source of boron to the oceans for Yellowstone National Park (Wyoming), Palmer and studying global boron cycling is boron in rivers. The Sturchio (1990) found <5UB values between -9.3 %o SUB values of rivers representing 39 percent of the and +4.4 %o. They suggest that the most negative total world discharge of water range from -5.9 %o to values may be explained by leaching of boron from +42.8 %o (Lemarchand and others, 2000). hydrothermally altered rhyolite. The highest SnB Surface and ground waters display a wide range values in hydrothermal fluids were measured by in boron isotopic composition. Ga'bler and Bahr Klotzli (1992) on Larderello geothermal field (Italy) (1999) were able to confirm the anthropogenic input samples (+21.8 %o to +29.1 %o). These high values of boron in ground water north of the Harz Mountains were attributed to meteoric waters incorporating boron in Germany. They identified a region with 6nB from marine sediments. The SUB value of-59 %o values between -3 %o and +3 %o and attributed these 18 values to perborates in detergents (exactly the range dissolved boron on clay minerals (Schwarcz and expected for perborates in the United States and others, 1969), giving rise to low SnB values of clays. Europe). Bassett and others (1995) were able to The <5UB of most modern marine sediments falls in distinguish water-recharge types in an injection site of the range -6.6 %o to +4.8 %o (Ishikawa and treated wastewater into an alluvial aquifer near El Nakamura, 1993). The boron isotopic composition is Paso, Texas, because the <5UB of native ground water controlled by mass balance of four major constituents: was +14 %0; that of municipal wastewater was detritus of continental origin, marine smectite, between +6 %o and +10 %o, and that of irrigation- biogenic carbonates, and biogenic silica. Detritus of affected water was greater than +40 %o. The highest continental origin, especially illite from eolian or SnB value found in the literature for a naturally fluvial transport, is the low d} [B end-member of occurring terrestrial material is +59.2 %o in brine from marine sediments (-13 %o to -8 %o). Biogenic Maar lakes from southwestern Victoria, Australia carbonate is the high end-member with <5UB values (Vengosh and others, 199la). The mole fraction of between +8.0 %o and +26.2 %o (Ishikawa and UB in this sample is 0.8107 andA(B) = 10.8207. Nakamura, 1993). These high UB concentrations are Another continental brine, also of largely marine the result of equilibrium uptake of boron from sea derived boron, is found in Laizhou Bay region of water. China with a <5UB value of+57.5 %o (Xiao and others, The (51 1B of ancient marine sediments is more 2001). Both of these brines have non-marine B/C1 negative (-17.0 %o to -5.6 %o) than that of modern ratios. sediments (Ishikawa and Nakamura, 1993). The more Igneous rocks The SUB of boron in the mantle negative SUB values can be caused by diagenesis, is -10 ± 2 %o, based on measurements of volcanic which promotes preferential removal of UB in calcium glasses and oceanic island basalts, which yield SUB = carbonate and silica during recrystallization, or by -9.9 ± 1.3 %o (Chaussidon and Marty, 1995). boron isotopic exchange during smectite/illite Unaltered mid-ocean ridge basalts from the East transition. Pacific Rise have SUB values in the range of-4.0 %o Organic boron Boron is an essential chemical to -1.7 %o (Spivack and Edmond, 1987; Chaussidon element for the healthy development of many plants. and Marty, 1995). As basalts undergo low Vanderpool and Johnson (1992) analyzed a variety of temperature alteration, UB and boron concentrations commercial produce grown in North America and are increased as discussed above. In a study in found a range of-7.5 %o to +29.3 %o in <5UB. Wieser Swaziland, tourmalines in granite have a narrow range and others (2001) analyzed the boron isotopic in SUB of between -17.0 %o and -13.5 %o (Trumbull composition of Coffee arabica bean samples from and Chaussidon, 1999). In a worldwide survey of around the world and found SUB values from -12 %o boron isotopic composition, Swihart and Moore for Peru "organic" beans to +19 %o for beans from (1989) observed a range in SUB of-12 %0 to -5 %o Tanzania. Wieser and others (2001) conclude that the for tourmaline in granite pegmatites. isotopic composition of local boron sources, such as Metamorphic rocks Tourmalines from a coarse, boron in the soil, fertilizer, and water, control the SUB zoned pegmatite and hydrothermal tourmalines in a values of the coffee beans. Thus, the boron isotopic study from Swaziland ranged in SnB value from composition of coffee can be used in quality- -23.0 %o to -16.6 %o (Trumbull and Chaussidon, assurance programs as the quality depends to a large 1999). Swihart and Moore (1989) found a range in extent on the genetic and geographic origin of the SnB of-22 %0 to +22 %o for tourmalines and coffee. metasedimentary rocks. Relatively high Williams and others (2001) analyzed boron concentrations of HB (6nB > -1 %o) were interpreted content and isotopic composition of kerogen in Gulf as indicating boron of marine or sedimentary origin. of Mexico sediments. They found large The sample of natural terrestrial origin with the lowest concentrations of organically bound boron (140 reported 11B content in figure 3 is kornerupine mg/kg) with a SnB value of-2 %o that may serve as a [(Mg,Fe2+)4(Al,Fe3+)6(Si04,B04)5(0,OH)2]from source for boron in deep sedimentary brines with low Antarctica (Wang and Xiao, 2000) with a <5HB value SUB values (< approximately 25 %o). of-34.2 %o. The mole fraction of UB of this specimen is 0.7961 and ^r(B) = 10.8062. Sediments The boron isotopic composition of sediments is variable. Boron isotopes are fractionated by 30 %o to 40 %o by preferential adsorption of 10B of 19 Carbon A(C) = 12.0107(8) Secondary reference materials (see table 10) are distributed by IAEA and (or) NIST and include Although carbon is the fourth most abundant various carbonates, natural gases, sugars, and an oil element in the universe after hydrogen, helium, and (Gonfiantini and others, 1995). Reference materials oxygen, its abundance in the Earth's crust is only .in a subset of these (Parr and Clements, 1991) are about fourteenth. Carbon occurs as the free element variably enriched in 13C and intended for use mainly (graphite and diamond), in fossil fuels (coal and in medical and biological tracer studies. petroleum), as the important atmospheric gas carbon dioxide, in carbonates of calcium and magnesium, and Ranges in Isotopic Composition in living and dead plants and animals. Important uses Carbon occurs in valence states between +4 and include energy production, steel making, sugar -4 in naturally occurring materials. Therefore, the manufacturing, water treatment, and respirators. range in isotopic variation of carbon-bearing materials The continual interaction of carbon among the is greater than 140 %o (table 11 and figure 4). Useful lithosphere, biosphere, atmosphere, and hydrosphere is compilations of carbon isotopic variations and isotope- called the carbon cycle. Carbon isotope ratios fractionation mechanisms include Friedman and commonly are used to investigate carbon-cycle CWeil (1977), Schwarcz (1969), Clark and Fritz processes. (1997) and Valley and Cole (2001). Carbon occurs primarily in 3 reservoirs on Earth, Reference materials and reporting of isotope sedimentary organic matter, the biosphere, and ratios sedimentary carbonates. These reservoirs differ in Beginning in the 1950's, isotope-abundance isotopic composition because of different isotope- measurements of carbon isotopes were expressed fractionation mechanisms. Kinetic isotope relative to Peedee belemnite (PDB), which was fractionation associated with photosynthesis assigned a <513C value of 0 %o. Because the supply of preferentially enriches plant material in 12C. This PDB is exhausted, IUPAC recommended in 1993 enrichment gives rise to organic sediments, coal, and (Coplen, 1994; IUPAC, 1994) that carbon isotope crude oil with <513C values near -25 %o and abundances be reported relative to VPDB (Vienna sedimentary carbonates near 0 %o (figure 4). PDB, the new primary reference for carbon isotope Carbonate and bicarbonate Total dissolved ratios having a Table 9. Carbon isotopic composition of a material with S13C = 0%o relative to VPDB [Atomic mass given in unified atomic mass units, u] Isotope Atomic Mass Mole Fraction 12C 12 u (exactly) 0.988 944(28) 13C 13.003 354 838(5) 0.011 056(28) From Audi and Wapstra (1993). From Chang and Li (1990) and Rosman and Taylor (1998 20 Table 10. Carbon isotopic composition of selected carbon-bearing isotopic reference materials [Values for <513C given in per mill relative to VPDB, defined by assigning an exact <513C value of+1.95 %o to NBS 19 carbonate] Reference Material Substance S13C Reference NBS 18 CaCOs (carbonatite) -5.01 ± 0.06 Stichler, 1995 NBS 19 CaCO3 (marble) +1.95 (exactly) Hut, 1987 IAEA-CO-1 CaCO3 (marble) +2.48 ± 0.03 Stichler, 1995 (IAEA Cl) IAEA-CO-8 CaCO3 -5.75 ± 0.06 Stichler, 1995 (IAEA KST) L-SVEC Li2CO3 ^6.48 ±0.1 5 Stichler, 1995 IAEA-CO-9 BaC03 -47.12 ±0.15 Stichler, 1995 (IAEA NZCH) USGS24 C (graphite) -15.99 ±0.11 Stichler, 1995 NBS 22 oil -29.74 ±0.1 2 Gonfiantini and others, 1995 IAEA-C-6 sucrose -10.43 ±0.13 Gonfiantini and others, (Sucrose ANU) 1995 NGS1 CH4 in natural gas -29.0 ± 0.2 Hut, 1987 NGS1 C2He in natural gas -26.0 ± 0.6 Hut, 1987 NGS1 CsHg in natural gas -20.8 ± 1 Hut, 1987 NGS2 CH4 in natural gas -44.7 ± 0.4 Hut, 1987 NGS2 C2H6 in natural gas -3 1.7 ±0.6 Hut, 1987 NGS2 CsHg in natural gas -25.5 ± 1 Hut, 1987 NGS2 CO2 in natural gas -8.2 ± 0.4 Hut, 1987 NGS3 CFLt in natural gas -72.7 ± 0.4 Hut, 1987 NGS3 C2H6 in natural gas -55.6 ± 5 Hut, 1987 IAEA-CH-7 polyethylene -31.83 ±0.11 Gonfiantini and others, (PEF1) 1995 NIST RM 8562 CO2 -3.76 ± 0.03 NIST, 1998 NIST RM 8563 CO2 -41.56 ±0.06 NIST, 1998 NIST RM 8564 CO2 -10.45 ± 0.04 NIST, 1998 occurring terrestrial specimen found in the literature. (carbonatites) range from -11.9 %o to +3.1 %o The mole fraction of 13C in this specimen is (Deines and Gold, 1973). A similar range of 0.011 466 and^(C) = 12.011 50. -11.9 %o to +0.2 %o usually is measured for The <513C values for igneous carbonates carbonates in kimberlites as well (Khar'kiv and 21 Table 11. Carbon isotopic composition of selected carbon-bearing materials [Values for <513C given in per mill relative to VPDB, defined by assigning an exact Minimum S13C Value Maximum <513C Value Substance <513C Reference S13C Reference CARBONATE AND BICARBONATE Sea water -0.8 Kroopnick, 1985 +2.2 Kroopnick, 1985 Other water -37.1 Nissenbaum and +37.5 Claypool and others, others, 1972 1985 Metamorphic and igneous -11.9 Deines and Gold, +24.8 Deines, 1968 rock 1973 Typical marine carbonate -6 Land, 1980 +6 Land, 1980 rock Other carbonate -64.5 Denser, 1970 +21.1 Deuser, 1970 CARBON DIOXIDE Air -8.2 Keeling and -6.7 Keeling, 1958 others, 1989 Soil gas -31.0 Aravena and +6.9 Notsu and others, others, 1996 2001 Volcanic gas -37 Valyayev and +23 Valyayev and others, others, 1985 1985 Oil, gas, coal, and -37.6 Wasserburg and +28 Whiticar and others, landfills others, 1963 1995 Commercial tank gas and -54 T. B. Coplen, -28.76 NIST, 1998 reference materials unpublished data OXALATES CaC2O4.xH2O -31.7 ZakandSkala, +33.7 Hofrnann and (whewellite) 1993 Bernasconi, 1998 CARBON MONOXIDE Air -31.5 Brenninkmeij er, -22 Stevens and others, 1993 1972 others, 1986; Mitchell, 1989); however, Deines have d C values between -12 %o and +5.7 %o (Weber (1968) has reported unusually high values (-10.2 %o and Raup, 1966; Lowenstam and Epstein, 1957; to +24.8 %o) for carbonates from a mica peridotite Murata and others, 1969). Marine CaCOs covers a dike near Dixonville, Pennsylvania (USA). Calc- broad <513C range from -60.6 %o (Hathaway and silicate rocks vary between -16 %o and +2 %o Degens, 1969) to +15.2 %o (Murata and others, (Schwarcz, 1969). 1969). "Typical" unaltered marine limestone tends to The testae, skeletons, and shells of marine biota have <513C values between -4 %o and +4 %0. Keith 22 Table 11. Carbon isotopic composition of selected carbon-bearing materials Continued Minimum S13C Value Maximum <513C Value Substance <513C Reference <513C Reference ORGANIC CARBON Land plants (C3 metabolic -35 O'Leary, 1988 -21 Smith and Turner, process) 1975 Land plants (C4 metabolic -16 Smith and Turner, -9 Smith and Turner, process) 1975 1975 Land plants (CAM -34 Deines, 1980 -10 O'Leary, 1988 metabolic process) Marine organisms -74.3 Paull and others, 1985 -2 Schwarcz, 1969 Marine sediments and -130.3 Elvert and others, +7 Deines 1980 compounds 2000 Coal -30 Deines, 1980 -19 Deines, 1980 Crude oil -44 Sofer, 1984 -16.8 Sofer 1984 Ethanol (naturally -32 Rauschenbach and -10.3 Rauschenbach and occurring) others, 1979 others, 1979 ELEMENTAL CARBON Graphite ^1 Deines, 1980 +6.2 Ghent and O'Neil, 1985 Diamonds -34.4 Galimov, 1985 +5 Harris, 1987 ETHANE Hydrocarbon gas -55.6 Hut, 1987 +6.6 Gerling and others, 1988 METHANE Air -50.6 Merritt and others, -39 Bainbridge and 1995 others, 1961 Marine and other sources -109 Whiticar and others, +12.7 Gerling and others, 1986 1988 Fresh water sources -86 Oremland and King, -50 Whiticar and others, 1989 1986 Commercial tank gas -51 K. Revesz, -38 K. Revesz, unpublished data unpublished data and Weber (1964) determined a mean of+0.56 %o for 1985) and mollusks (Keith and others, 1964) have a selected group of 272 marine limestones. Unusual <513C values between -19.4 %o and +7.0 %o. Land values usually are found in association with organic snail shells vary between -12.0 %o and +0.5 %o matter, methane, and (or) sulfur. (Tamers, 1970; Goodfriend and Magaritz, 1987). The carbonate of freshwater brachiopods (Abell, Freshwater CaCOs has di-13 C values between -17.7 %o 23 Atomic Weight 12.0095 12.0100 12.0105 12.0110 12.0115 13, Mole Fraction of C 0.0095 0.0100 0.0105 0.0110 0.0115 , I . , . , | , , i | , , , , | , , , , | ^STANDARD ATOMIC WEIGHT 1 ^ CARBONATE & BICARBONATE 1 Sea water r Other water NBS 18 | Metamorphic & igneous rock Typical marine carbonate rock L-SVEC NBS 19 IAEA-CO-1 Other carbonate IAEA-CO-9 ' I CARBON DIOXIDE Air . I Soil gas | Volcanic gas NGS2 ' Oil, gas, coal, and landfills RM8564* I Commercial tank gas and reference materials RM8563 RM8562 I OXALATES I CaC2O4-xH2O (whewellite) I I CARBON MONOXIDE Air ___ I I ORGANIC CARBON I Land plants (C3 metabolic process) IAEA-C-6 I Land plants (C4 metabolic process) Land plants (CAM metabolic process) Marine organisms I ( Coal NBS 22 I Crude oil Ethanol (naturally occurring) I I ELEMENTAL CARBON USGS24^ * Graphite * I Diamonds I ETHANE NGS3 NGS2 NGS1 Hydrocarbon gas I METHANE Air ___ I NGS3 NGS2 NGS1 j Marine and other sources Fresh water sources I Commercial tank gas I I , , i 1 , , , I , , I , , , I i , i 1 . i , 1 , , . 1 i . , 1 i i . 1 . . 1 . -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 513C, in %o relative to VPDB Figure 4. Carbon isotopic composition and atomic weight of selected carbon-bearing materials. The SnC scale and 13C mole-fraction scale were matched using the data in table 9; therefore, the uncertainty in placement of the atomic-weight scale and the 13C mole-fraction scale relative to the <513C scale is equivalent to ±2.5 %o. 24 (Clayton and Degens, 1959, as cited in Murata and -27 %o were measured by Mook (1986) in air near others, 1969) and +6.3 %o (O'Neil and Barnes, 1971). cities and industrial areas, in plant populations, and in Keith and Weber (1964) measured an unusual value rivers. CO2 respired by humans ranges between of -24.2 %o, which they did not include hi their mean -23.5 %o and -18.7 %o (Epstein and Zeiri, 1988). In of-4.93 %o for 158 freshwater limestone samples. addition, <513C values between -42.2 %0 and -28.2 %0 Dolomite, CaMg(CO3)2, has <513C values ranging have been measured for CO2 in a cave in the Ukraine between -64.5 %o and +21.1 %0 (Deuser, 1970). Most (Klimchuk and others, 1981). platform dolomites have <513C values within a smaller The 25 inclusion may be substantially smaller for a given reaction is carboxylation of ribulosebisphosphate sample type than the range indicated above (-35 %o (RuBP) to the Cs-product phosphoglycerate, which and +10 %o). generally results in <$13C of plants between -34 %o and The 813C values of CO2 from oil, gas, coal, -24 %0 (Winkler, 1984), but as low as -35 %o landfills, and marine sediments range from -38 %o to (O'Leary, 1988) and as high as -21 %o (Smith and about +28 %o (Valyayev and others, 1985; Deines, Turner, 1975). C3 plants tend to grow in cool, moist, 1980; Whiticar and others, 1995; Wasserburg and shaded areas (Ambrose and DeNiro, 1989) and others, 1963). However, most values fall between comprise 80 to 90 percent of plants. All trees, most -24 %0 and +2 %0 (Valyayev and others, 1985). shrubs, some grasses from temperate regions and Oxalates The oxalate, whewellite tropical forests, and common crops such as wheat, rice, (CaCzC^-tbO), is a relatively rare mineral found with oats, rye, sweet potatoes, beans, and tubers utilize the carbonaceous materials. Whewellite formation seems C3 pathway (Winkler, 1984). to be related to mobilization of oxalates released A second reaction is carboxylation of during decomposition of organic matter (Zak and phosphoenolpyruvate to the C* product oxalacetic acid. Skala, 1993). Whewellites from low temperature This fixation is more efficient leading to less depletion hydrothermal veins had SnC values as negative as in 13C; the <513C of C4 plants ranges between -16 %o -31.7 %o. Much more positive values can be and -9 %o (Smith and Turner, 1975). C4 plants, such associated with bacterial processes. The most positive as maize, sugar cane, sorghum, and grasses in value is +33.7 %o (S. Bernasconi, Geologisches Australia, Africa, and other subtropical, savannah, and Institut, ETH-Zentrum, Zuerich, Switzerland, written arid regions, tend to grow in hot, dry, sunny communication, 1997). environments (Winkler, 1984; Ambrose and DeNiro, Carbon monoxide Carbon monoxide is an 1989). important atmospheric trace gas and also a major Plants that fix carbon by Crassulacean Acid pollutant in most large cities (Brenninkmeijer, 1993). Metabolism (CAM) can utilize either the C3 or C4 Principal sources of carbon monoxide (Seiler, 1974) cycles (Schidlowski, 1987; Deines, 1980; O'Leary, include oxidation of methane and non-methane 1988); thus their 513C values cover the range of both hydrocarbons, biomass burning (mostly tropical C4 and C3 plants (-34 %o to -10 %o). Succulents forests and savanna), transportation, industry, heating, such as agave, prickly pear, yucca, and pineapple and oceans, and vegetation. The primary sinks of some submerged aquatic plants utilize CAM carbon atmospheric methane are oxidation by the hydroxyl fixation. The isotopic composition of CAM plants radical (OH) and uptake by soils. Its average especially is sensitive to factors such as water supply, residence time in the atmosphere is about 2 months; light intensity, and temperature, since CAM plants can however, its global budget is complex. utilize either the C4 or C3 cycles depending on Brenninkmeijer (1993) measured the S13C of carbon environmental conditions (Deines, 1980). monoxide in the atmosphere in Antarctica in order to Animals and microbial heterotrophs generally obtain the isotopic composition of unpolluted have SnC values within 2 %o of their food supply; atmospheric carbon monoxide and found S 1 ^C values however, the <513C values of various organs and tissues between -31.5 %o and -27 %o. The range reported by within a single organism can have a wider range (Fry Stevens and others (1972) is between -31 %o and and Sherr, 1984). The 513C values of fresh tissues and -22 %0. the collagen and hydroxyapatite from bones and teeth Organic carbon The biological assimilation of have been applied to food web studies and carbon by plants generally results in depletion of 13C reconstructions of prehistoric diet and vegetation in the organism's tissues relative to the carbon sources patterns (Fry and Sherr, 1984; Tieszen and Boutton, (CO2 and HCO31. The magnitude of the 13C depletion 1988; Ambrose and DeNiro, 1989). For example, depends on the species and the carbon fixation geographic variations of the <513C values of hair in pathways utilized, environmental factors such as humans compares favorably with the 13C depleted diets temperature, CO2 availability, light intensity, pH of of Germans (<513C = -23.6 %o), the seafood and corn water, humidity, water availability, nutrient supply, diets of Japanese (<513C = -21.2 %o), and the corn diets salinity, cell density, age of photosynthesizing tissue, of Americans (<513C = -18.1 %o), according to and oxygen concentration (Berry, 1988). Nakamura and others (1982). Plants assimilate carbon using 2 different Isotope ratio analyses of organisms found in the pathways, which leads to a classification of 3 literature primarily have been confined to analysis of photosynthetic groups. The predominant fixation molecules or whole tissues. Brenna (2001) points out 26 that, "Natural isotopic variability, particularly on an Sherr, 1984). Freshwater organisms tend to have more intramolecular level, is likely to retain more negative <513C values than those from marine physiological history. Because of ubiquitous isotope environments; this may result from the lower pH fractionation, every sterochemically unique position in values and thus higher CO2 concentrations found in every molecule has an isotope ratio that reflects the freshwater settings (Schwarcz, 1969). Plankton tends processes of synthesis and degradation." Brenna to be more depleted in 13C than sessile plants in the (2001) makes a strong case that future studies of same environment (Deines, 1980), possibly because of physiological isotope fractionation should involve the higher concentration of 13C-depleted lipids in position-specific isotope analysis and should reveal the plankton (Schwarcz, 1969). relationship of diet and environment to observed Methanogenic bacteria grown in the laboratory isotope ratio. A remarkable example that shows that under varying and sometimes extreme conditions have physiological isotope-abundance variations are had 613C values ranging from -41 %o to +6 %o preserved in some materials for extended periods is the (Schidlowski, 1987). Zyakun and others (1981) study by Slatkin and others (1985) that compared the determined that methane oxidizing bacteria were <513C of human cerebellar autopsy tissue from depleted in 13C by 10 %o to 20 %o relative to the American-born Americans, European-born Americans source methane. The range of 813C values of (immigrants residing in the U.S. for an average of 46 chemoautotrophic bacteria in natural settings probably years), and European-born Europeans. Cerebellar is very broad because of the large variation in S13C DNA from European-born Europeans (<513C = -20.34 ± values in CO2 and CFLt. 0.30 %o) was similar to that of European-born The <513C value of sedimentary organic matter is Americans ( 27 1989) and localized Archean (Schoell, 1988) Ethane Low temperature serpentinization of communities. Furthermore, organic matter ophiolitic rocks generates free hydrogen along with substantially depleted in 13C has been found near sulfur minor amounts of methane and ethane. A study by deposits with S13C values from -89.3 %o to -82.5 %0 Fritz and others (1992) finds <513C values of ethane as (Kaplan and Nissenbaum, 1966). The material of high as -11.4 %o. Hydrocarbons are entrapped in the natural terrestrial origin with the lowest 13C content Zechstein evaporites of northern Germany. Gases in found in the literature is crocetane (2,6,11,15- the potash layers are highly enriched in 13C with <513C tetramethylhexadecane), produced at cold seeps of the values as positive as +6.6 %o (Gerling and others, eastern Aleutian subduction zone, with a value of 1988). The mode of formation is still uncertain -130.3 %o (Elvert and others, 2000). The mole although hypotheses include (1) maturation of organic fraction of 13C of this specimen is 0.009 629 and matter rich in 13C, (2) transformation of CO2 enriched Ar(C) - 12.009 66. in 13C to CH4, (3) unknown bacterial isotope The isotopic composition of petroleum is fractionation, and (4) abiotic gas formation during constrained primarily by the kerogen 13C content and halokinesis. The most negative <513C found in the the sedimentary environment (Sofer, 1984). The <513C literature for a bacterially formed ethane is -55 %o. of petroleum tends to be a few per mill more negative The 613C of the ethane component of the NGS3 than the source kerogen (Deines, 1980) and ranges natural gas reference material discussed by Hut (1987) from -44 %o to about -17 %o (Sofer, 1984). is -55.6 %o. Rauschenbach and others (1979) analyzed the Methane The two major methane production <513C of ethanol in a variety of alcoholic beverages and processes are (1) diagenesis of organic matter by found a range from -32 %o to -10.3 %o. This range is bacterial processes, and (2) thermal maturation of similar to the range found in C3 and C4 plants used organic matter. Biogenic methane, produced by to produce these beverages. According to K.P. Horn bacterial processes during the early stages of (Liquor Control Board of Ontario, Ontario, Canada, diagenesis, is formed in freshwater and marine written communication, 2001) ethanol from pure malt environments, recent anoxic sediments, swamps, salt whisky ranges from -26 %o to -25 %o, and bourbon is marshes, glacial till deposits, and shallow dry-gas about -12 %o. In pure malt products, the 28 anthropogenic sources including swamps, rice fraction of 15N from measured <515N values (Coplen paddies, ruminants, termites, landfills, fossil-fuel and others, 1992). De Bievre and others (1996) production, and biomass burning. The (513C of reported uncalibrated measurements corrected for mass atmospheric methane is relatively constant, generally spectrometer inlet fractionation effects that yield a ranging between -50.58 %o and -46.44 %o (Merritt 14N/15N ratio for atmospheric nitrogen of 271.87 ± and others, 1995) although values as positive as 0.11, in agreement with the recommended value of -39 %o have been reported (Bainbridge and others, 272. 1961). Two commercial tanks of methane measured Table 13 lists 6 ammonium sulfates (IAEA-N1, during this study by K. Revesz (unpublished data) IAEA-N2, USGS25, USGS26, IAEA-305A, and had <513C values of-51 %o and -38 %o. IAEA-305B), 2 potassium nitrates (IAEA-N3 and USGS32), 2 ureas (IAEA-310A and IAEA-3106), and 1 tank of purified N2 gas (NSVEC) that are secondary Nitrogen A(N) = 14.0067(2) isotopic reference materials internationally distributed by IAEA and (or) NIST. "Provisional certified <515N Although nitrogen is about twenty-fifth in crustal values" have been reported for IAEA-305A, abundance, it comprises 78.1 percent of the IAEA-305B, IAEA-310A, and IAEA-31 OB, which are atmosphere by volume. A primary use of nitrogen enriched in 15N and intended for use mainly in gas is as an inert atmosphere in iron and steel medical and biological tracer studies (Parr and production and in the chemical and metallurgical Clements, 1991). A comparison test was completed industry (Greenwood and Earnshaw, 1997). Large for the others, which have been distributed mainly to quantities of nitrogen are used in fertilizers and geologic, hydrologic, and soils science laboratories chemical products. More moles of anhydrous (Bohlke and Coplen, 1995). ammonia are produced worldwide than any other nitrogen-bearing compound. The continual interaction Ranges in Isotopic Composition of nitrogen among the lithosphere, biosphere, Naturally occurring nitrogen-bearing materials atmosphere, and hydrosphere is called the nitrogen have widely varying isotopic compositions ranging cycle. Nitrogen isotope ratios commonly are used to over more than 200 %o, in large part because of redox investigate nitrogen-cycle processes. transformations among the wide range of valence states (from -3 to +5). Ranges in the stable isotopic Reference materials and reporting of isotope composition of naturally occurring nitrogen-bearing ratios materials are shown in table 14 and figure 5. The primary reference for relative isotope Compilations of nitrogen isotope-abundance variations abundance measurements of nitrogen isotopes is and isotope-fractionation mechanisms include Letolle atmospheric N2, which is homogeneous with respect (1980), Heaton (1986), Hiibner (1986), Owens (1987), to analytical uncertainties with common analytical and Kendall (1998). techniques (Mariotti, 1983) and is assigned a <515N Nitrate Limited data indicate that nitrate in value of 0 %o. Nitrogen isotope ratios are determined precipitation generally has <515N values near 0 %o or on gaseous N2 using electron impact ionization mass slightly higher. Major studies in Germany and South spectrometry and commonly are measured with a l-o Africa both indicate that <515N values of nitrate in rain standard deviation of ±0.1 %o. are higher in cold seasons than in warm seasons The absolute isotope ratio (14N/15N) of (Heaton, 1987; Freyer, 1978a). The range of nitrate atmospheric nitrogen was measured by Junk and Svec 29 Table 12. Isotopic composition of atmospheric nitrogen [Atomic mass given in unified atomic mass units, u] Isotope Atomic Mass Mole Fraction 14N 14.003 074 0074(18) 0.996 337(4) 15N 15.000 108 973(12) 0.003 663(4) A From Audi and Wapstra (1993). B From Rosman and Taylor (1998) and Junk and Svec (1958). approximately 0 %o and +20 %o. Values lower than Bohlke and others (2000) report a range of <515N about +8 %o are typical of agricultural areas where values in nitrite from sewage-contaminated ground artificial fertilizers are used, whereas values higher water from about -30 %o to +55 %o. than +8 %o commonly result from nitrification of Nitrogen oxide gases The sources, sinks, and animal wastes such as sewage and manure. Published fluxes of nitrogen oxides in the atmosphere are not values greater than +20 %o are becoming increasingly well known, nor are their isotopic compositions. common, especially in isotopically fractionated Limited data indicate that atmospheric N2 30 Table 13. Nitrogen isotopic composition of selected nitrogen-bearing isotopic reference materials [Values for <515N given in per mill relative to N2 in air] Reference Material Substance <515N Reference NSVEC N2 gas -2.77 ± 0.05 Bohlke and Coplen, 1995 NBS-14 N2 gas -1.18 Kendall and Grim, 1990 IAEA-N-1 (NH4)2SO4 +0.43 ± 0.07 Bohlke and Coplen, 1995; Gonfiantini and others, 1995 IAEA-N-2 (NH4)2SO4 +20.32 ± 0.09 Bohlke and Coplen, 1995; Gonfiantini and others, 1995 IAEA-NO-3 KNO3 +4.69 ± 0.09 Bohlke and Coplen, (IAEA-N3) 1995; Gonfiantini and others, 1995 IAEA-305A (NH4)2SO4 +39.8 ± 0.5 Parr and Clements, 1991 IAEA-305B (NH4)2S04 +375.3 ± 2.3 Parr and Clements, 1991 IAEA-3 10A CO(NH2)2 +47.2 ± 1.3 Parr and Clements, 1991 IAEA-31 OB CO(NH2)2 +244.6 ± 0.8 Parr and Clements, 1991 IAEA-311 (NH4)2SO4 +4693 ± 57 Parr and Clements, 1991 USGS25 (NH4)2SO4 -30.25 ± 0.38 Bohlke and Coplen, 1995 USGS26 (NH4)2SO4 +53.62 ± 0.25 Bohlke and Coplen, 1995 USGS32 KNO3 +179.2 ± 1.3 Bohlke and Coplen, 1995 dominated by dissolved atmospheric N2, which is volcanic and geothermal environments may occur in fractionated only slightly during dissolution. Some response to mineral devolatilization, oxidation- anoxic ground waters contain an additional N2 reduction reactions involving aqueous ammonia, and component derived from denitrification that is other reactions. N2 from sedimentary basins, isotopically distinct from the atmospheric component. including oil and hydrocarbon gas deposits, has a N2 gases emanating from volcanoes and hot springs large range of reported isotopic compositions, only generally are mixtures of atmospheric N2 and N2 from part of which can be attributed to variations in organic the Earth's mantle and (or) crust (including sediments, source materials. Isotope fractionation of natural if present at depth). Isotope fractionation of N2 in gases may be caused by biological activity, thermal 31 Table 14. Nitrogen isotopic composition of selected nitrogen-bearing materials [Values for Minimum 32 Table 14. Nitrogen isotopic composition of selected nitrogen-bearing materials Continued Minimum <515N Value Maximum <515N Value Substance <515N Reference J15N Reference NITROGEN GAS Air 0 Mariotti, 1983 0 Mariotti, 1983 Ground waters -3 Vogel and others, +5 Smith and others, 1981 1991 Volcanic gases and hot -10 Marty and others, +16 Allard, 1983 springs 1991 Sedimentary basins -49 Stroud and others, +46 Eichmann and 1967 others, 1971 Commercial tank gas -5 Shearer and Legg, +3 Zschiesche, 1972 1975 ORGANIC NITROGEN Plants and animals -49 Wada and others, +3 1 Wada and others, 1981 1981 Marine particulate organic -3 Altabet and +46 Altabet and matter McCarthy, 1985 McCarthy, 1985 Bituminous sediments, -3 Hoering, 1955 +13 Rigby and Batts, peat, and coal 1986 Crude oil +1 Hoering and Moore, +7 Hoering and 1958 Moore, 1958; Eichmann and others, 1971 Soils -29 Wada and others, +38 Mizutani and 1981 others, 1986 Synthetic reagents and -3 Shearer and others, +6 Shearer and others, fertilizers 1974 1974 Biological fertilizers +3 Shearer and others, +15 Shearer and others, 1974 1974 NITROGEN IN ROCKS Metamorphic rocks +1 Bebout and Fogel, +17 Haendel and others, 1992 1986 Igneous rocks -36 Mattey and others, +31 Mayne, 1957 1985 Diamonds -37 Mattey and others, +14 Mattey and others, 1985 1985 33 Table 14. Nitrogen isotopic composition of selected nitrogen-bearing materials Continued Minimum d N Value Maximum <515N Value Substance 5N Reference Reference AMMONIUM Air (ammonia gas) -15 Heaton, 1987 +28 Moore, 1977 Air (aerosols and -14 Freyer, 1978a +14 Moore, 1974 precipitation) Sea water and estuaries +2 Velinsky and others, +42 Velinsky and 1991 others, 1989 Soil extracts -7 Freyer, 1978b +50 Mizutani and others, 1986 Volcanic gas condensates -31 Volynets and others, +13 Hoering, 1955; 1967 Volynets and others, 1967 Synthetic reagents and -5 Shearer and others, +11 Drechsler, 1976 fertilizers 1974 lakes (Wada and others, 1981). Animals generally values from -36 %o to +20 %o. Rocks in the Earth's have higher <515N values than their diets, such that continental crust, including granitic igneous rocks and there is a fairly consistent increase in <515N with metamorphosed sedimentary rocks, have a range of trophic level in a given setting. There is evidence for <515N values similar to that of most bituminous minor isotope fractionation of nitrogen in some coals sediments and soils, probably because most nitrogen and sedimentary rocks that have been partially in crustal rocks represents transformed and devolatilized by high temperature metamorphism. redistributed organic matter. The nitrogen in most However, much of the isotopic variation in these granitic and metamorphic rocks occurs largely as materials probably is related to the type and source of ammonium substituting for potassium in silicate organic matter preserved. The <515N values reported minerals such as micas and feldspars. Because of from crude oils are relatively uniform compared to the isotope fractionation by devolatilization reactions more variable data from modern organisms and (rock ammonium » fluid N2), <515N values of organic-rich sediments. Soil organic nitrogen in most metamorphic rocks tend to increase with metamorphic natural and agricultural settings is slightly enriched in grade. 15N relative to air N2; average values of <515N typically Ammonium Particulate ammonium in air are between 0 %o and +10 %o. Unusually high and apparently has 34 Atomic Weight 14.0064 14.0066 14.0068 14.0070 14.0072 Mole Fraction of 15N 0.0034 0.0036 0.0038 0.0040 0.0042 STANDARD ATOMIC WEIGHT NITRATE Air (aerosols and precipitation) Sea water and estuaries Ground water and ice Soil extracts Desert salt deposits IAEA-NO-3 Synthetic reagents and fertilizers USGS32 +179 NITRITE Ground waters Synthetic reagents NITROGEN OXIDE GASES N2O in air (troposphere) N2O in sea water N2O in ground water - NOX in air NOX from nitric acid plant + -150 NITROGEN GAS AIR Air Ground waters Volcanic gases and hot springs Sedimentary basins Commercial tank gas 'NSVEC T ORGANIC NITROGEN Plants and animals Marine particulate organic matter Bituminous sediments, peat, and coal Crude oil Soils Synthetic reagents and fertilizers IAEA-3106 +245 Biological fertilizers IAEA-31 OA NITROGEN IN ROCKS Metamorphic rocks Igneous rocks Diamonds AMMONIUM Air (ammonia gas) Air (aerosols and precipitation) Sea water and estuaries Soil extracts Volcanic gas condensates USGS25 IIAEA-N-1-N-1 IAEA-305A Synthetic reagents and fertilizers IAEA-3056 +375 -> IAEA-N-2 USGS26 . . I . . i I , I ... I -80 -40 0 40 80 120 160 815N, in %0 relative to N2 in Air Figure 5. Nitrogen isotopic composition and atomic weight of selected nitrogen-bearing materials. The <515N scale and 15N mole-fraction scale were matched using the data in table 12; therefore, the uncertainty in placement of the atomic-weight scale and the 15N mole-fraction scale relative to the <515N scale is equivalent to ±1.1 %o. 35 volcanic steam also are highly variable. Average <515N are determined on gaseous CO2, O2, or CO using values of synthetic ammonium reagents and fertilizer electron impact ionization mass spectrometry and are slightly lower than those of synthetic nitrate commonly are measured with a l-o standard deviation chemicals in general, but there is much overlap. of ±0.1 %o. Although no investigator has measured the absolute abundances of all three oxygen isotopes, Oxygen 4(0) = 15.9994(3) Baertschi (1976) measured the 18O/16O ratio of VSMOW reference water and Li and others (1988) Oxygen is the most abundant element in the measured the absolute 17O concentration in VSMOW Earth's crust, occurring both as the free element and in reference water. From these measurements, the numerous compounds. Oxygen gas and liquid are absolute isotope abundances of VSMOW reference produced on a large scale by fractional distillation of water can be determined (table 15). liquid air. Only nitrogen (liquid and gas) and sulfuric Table 16 and figure 6 list various carbonates, a acid are produced in the United States on a larger silica sand, three sulfates, three carbon dioxide scale. Important uses of purified oxygen include steel gases, and a biotite that are secondary isotopic manufacturing in the Bessemer process, oxy-gas reference materials for environmental, geochemical, welding and metal cutting, chemical production (TiOi, and hydrological studies. These are distributed by ethylene oxide, and other compounds), hospital IAEA and (or) NIST. The reference material, NBS oxygen tents, and oxidant for rocket fuels. 127 barium sulfate, is plotted in figure 6 as a sulfate mineral although technically the sulfate was derived Reference materials and reporting of isotope from ocean water. Silicates are among the most ratios difficult materials to analyze because of the strong Since 1993, the Commission has recommended silicon-oxygen bonds in these molecules. During the that oxygen isotope ratios be reported relative to last decade a COz-laser-based method has produced VSMOW water or relative to VPDB (defined by good results, agreeing with a <518O value of +9.59 %o adopting an exact <518O value of-2.2 %0 for NBS 19 for NBS 28 (Spicuzza and others, 1998; Hut, 1987). CaCOs) on a scale normalized such that the exact "Provisional certified SISO values" have been reported for IAEA-304A and IAEA-304B waters, <518O of SLAP water is -55.5 %o, relative to VSMOW t o (IUPAC, 1994; Coplen, 1994). Using the data in which are enriched in O and intended for use Coplen and others (1983) and given a value of mainly in medical and biological tracer studies (Parr and Clements, 1991). Note that these reference -2.2 %0 for the SISO value of NBS 19 relative to t o VPDB, the VPDB scale can be related to the materials were made with O enriched water; thus, VSMOW scale by the relative abundances of 16O, 17O, and 18O may not vary systematically with mass as they do in normal = 0.97001 Table 15. Oxygen isotopic composition of VSMOW reference water [Atomic mass given in unified atomic mass units, u] Isotope Atomic Mass Mole Fraction 16Q 15.9949146223(25) 0.997 6206(5) 170 16.999 131 50(22) 0.000 3790(9) 18Q 17.999 1604(9) 0.0020004(5) A From Audi and Wapstra (1993). B From Baertschi (1976) and Li and others (1988). 36 Table 16. Oxygen isotopic composition of selected oxygen-bearing isotopic reference materials [Values for <518O given in per mill relative to VSMOW or WDB on scales normalized such that the <518O of SLAP is -55.5 %o relative to VSMOW; the WDB scale is defined (Hut, 1987) by assigning an exact <518O value of-2.2 %o to NBS 19 carbonate; °C = degrees Celsius] Reference Substance <5180 Relative Reference Material to VSMOW water 0 (exactly) VSMOW Gonfiantini, 1978 GISP water -24.78 ± 0.08 VSMOW Gonfiantini and others, 1995 SLAP water -55.5 (exactly) VSMOW Gonfiantini, 1978 NIST RM 8562 CO2 -8.45 ±0.11 VPDB NIST, 1998 NIST RM 8563 CO2 -23.72 ±0.11 WDB NIST, 1998 NIST RM 8564 CO2 +0.19 ±0.10 VPDB NIST, 1998 NBS 30 biotite -5.24 ± 0.25 VSMOWA Gonfiantini and others, 1995 NBS 18 CaCO3 -23.00 ± 0.06 VPDB Coplen and others, 1983; (carbonatite) Gonfiantini and others, 1995; Stichler, 1995 NBS 19 CaC03 (calcite) -2.2 (exactly) VPDB Hut, 1987 IAEA-CO-1 CaCO3 -2.44 ±0.07 VPDB Stichler, 1995 IAEA-CO-8 CaCO3 -22.67 ± 0.19 WDB Stichler, 1995 (IAEA KST) IAEA-CO-9 BaCO3 -15.28 ± 0.09 WDB Stichler, 1995 (IAEA NZCH) L-SVEC Li2CO3 -26.64 ± 0.25 WDB Stichler, 1995 NBS 28 SiO2 +9.58 ± 0.09 VSMOWA Gonfiantini and others, 1995 (silica sand) IAEA-NO-3 KNO3 +25.3 ± 0.7 VSMOWA Kornexl and others, 1999 NBS 127 BaSO4 +8.7 ± 0.2 VSMOWA Kornexl and others, 1999 IAEA-SO-5 BaSO4 +12.0 ± 0.2 VSMOWA Kornexl and others, 1999 IAEA-SO-6 BaSO4 -11.0 ±0.2 VSMOWA Kornexl and others, 1999 Using an oxygen isotope-fractionation factor between gaseous CO2 and H2O of 1.0412 at 25 °C. Ranges in Isotopic Composition Garlick (1969), Friedman and O'Neil (1977), Valley Oxygen exhibits a large variation in isotopic and others (1986), Kyser (1987), Clark and Fritz composition (> 160 %o), partly because it is found in (1997), Valley and Cole (2001), and Schmidt and valence states between -2 and 0 in naturally occurring others (2001). Values of <517O and <518O are expressed materials (table 17 and figure 6). Compilations of relative to VSMOW in this report unless otherwise isotopic variations and isotope-fractionation specified. mechanisms of oxygen-bearing materials include 37 Table 17. Oxygen isotopic composition of selected oxygen-bearing materials [Values for Minimum S 18,O Value Maximum S 18,O Value <518O Substance Reference O Reference OXYGEN GAS Air +23.8 Kroopnick and Craig, +23.8 Kroopnick and Craig, 1972 1972 WATER Sea water -1 Craig, 1967 +0.6 Craig, 1967 Continental water -62.8 Aldaz and Deutsch, +31.3 Fontes and 1967 Gonfiantini, 1967 Fruit juice and wine -4.4 Bricout and others, 1973 +15.3 Caldwell, 1995 CARBON MONOXIDE Air -6.9 Brenninkmeijer, 1993 +1.7 Brenninkmeijer, 1993 Commercial tank gas -229 WJ. Showers, North +7.6 R. A. Werner, Max- Carolina State Planck-Institute for University, Raleigh, Biogeochemistry, North Carolina, written Jena, Germany, communication, 2002 written communication, 2001 CARBON DIOXIDE Air +40 Francey and Tans, 1987 +53.0 Thiemens and others, 1991 Commercial tank gas +3.9 Coplen and others, 1983 +22.2 NIST, 1998 CARBONATES Typical marine +26 Murata and others, 1969 +34 Murata and others, carbonate 1969 Igneous (carbonatite) -1.3 Garlick, 1969 +7.7 Suwa and others, 1975 Other carbonate -20.5 Faure and others, 1988 +36.4 Makhnach and others, 1994 NITROGEN OXIDES N2O (air and water) +20 Perez and others, 2000 +109 Yoshinari and others, 1997 Nitrate (air and water) -2.5 Amberger and Schmidt, +76 Williard and others, 1987 2001 38 Table 17. Oxygen isotopic composition of selected oxygen-bearing materials Continued Minimum d 18,O Value Maximum 6 18.O Value Substance <518O Reference <518O Reference OXIDES Al and Fe oxides -15.5 Yapp, 1993 +16 Bird and others, 1989 Chert +9.4 Knauth and +45 Labeyrie and Lowe, 1978 others, 1986 PHOSPHATES Skeletal parts +6 Kolodny and +26.7 Bryant and others, 1983 others, 1994 Phosphorite rocks +8.6 Longinelli and +25.1 Shemesh and Nuti, 1968 others, 1983 SILICATES -16.2 Blattner and +34.9 Bohlke and others, 1997 others, 1984 SULFATES Air -19 Norman and +14.1 Mizutani and Krouse, 1992 Rafter, 1969 Sea water +9.3 Longinelli, 1989 +9.6 Longinelli, 1989 Other water -19.8 Hendry and +23.2 Longinelli and others, 1989 Craig, 1967 Minerals -10.0 Yonge and +31.2 Cecile and others, Krouse, 1987 1983; Sakai, 1971 PLANTS AND ANIMALS Cellulose, lipids, and -4.3 Dunbar and +37.0 Sternberg and tissue Wilson, 1982 others, 1984 Oxygen isotope fractionations in naturally (2000) report <517O and <518O values of+11.1 %o and occurring materials generally are mass dependent. For +12.5 %o for sulfate in sand crystals from Scotts example, Meijer and Li (1998) find <517O values to be Bluff, Nebraska (USA), a 4.6 %0 enrichment in 17O 0.5281 ± 0.0015 times <518O values in natural waters relative to the expected mass-dependent value. This is on the VSMOW scale. However, mass-independent the first sulfate deposit on the Earth's surface reported d O and d 0 isotopic variation has been observed in to be enriched in 17O. 17O enrichments in excess of atmospheric O3, O2, N2O, H2O2, CO, CO2, sulfate 10 %o (relative to mass-dependent values) have been aerosols, and nitrate aerosols (Thiemens and others, determined for atmospheric nitrate (Galanter and .1991; Thiemens and others, 1995; Johnson and others, others, 2000; Michalski and Thiemens, 2000) and in 2001; Thiemens, 2001). For ozone, this effect may be excess of 20 %o for nitrate from the Atacama Desert, caused in part by discrimination between symmetric Chile (J.K. Bohlke, unpublished data). and asymmetric isotopic species during photochemical Oxygen gas Dole and others (1954) observed reaction (Gao and Marcus, 2001). Bao and others that atmospheric oxygen is constant in 180 content. 39 Atomic Weight 15.9990 15.9992 15.9994 15.9996 15.9998 Mole Fraction of 18O 0.0019 0.0020 0.0021 0.0022 , . , 1 STANDARD ATOMIC WEIGHT ! . ______' ' I 1 OXYGEN GAS \ Air \ WATER Sea water q. AP VSMOW Continental water 9 GISP * Fruit juice and wine 1 CARBON MONOXIDE __ l_ Air 1 1 CARBON DIOXIDE 1 Air , RM 8562 ~ ~ Commercial tank gas and reference gas RM8563* RM8564 ' NBS 19 CARBONATES I/4EA-CO-8 ^A-C°-1 Typical marine carbonate i ^NBS18^^ Igneous (carbonatite) ^^^^P Other carbonate L-SVEd *IAEA*CO-9 NITROGEN OXIDES N2O (air and water) Nitrate IAEA-NO-3 OTHER OXIDES Al and Fe oxides Chert PHOSPHATES Skeletal parts Phosphorite rocks SILICATES NBS 30 NBS 28 SULFATES Air Sea water NBS 127 Other water I Minerals IAEA-SO-6 IAEA-SO-5 PLANTS AND ANIMALS Cellulose, lipids, and tissue . . i i i i i i i , , , I , , , , , , I , , , I , , , I , , , I , , , I , , , -60 -40 -20 0 20 40 60 80 100 120 18 8'°O, in %0 relative to VSMOW -80 -60- -40 -20 20 40 60 80 18 8 IOO, in %o relative to VPDB Figure 6. Oxygen isotopic composition and atomic weight of selected oxygen-bearing materials. The dl O scale and 18O mole-fraction scale were matched using the data in table 15; therefore, the uncertainty in placement of the atomic-weight scale and the 18O mole-fraction scale relative to the <518O scale is equivalent to ±0.3 %o. 40 Kroopnick and Craig (1972) determined a <518O value water. Bricout and others (1973) showed that natural for atmospheric oxygen of+23.5 %o using an oxygen orange juice could be distinguished from orange juice isotope-fractionation factor between water and CC>2 of reconstituted from concentrate and water from higher 1.0409. However, that isotope-fractionation factor latitudes containing less I8O. appears to be too low and we use herein an oxygen The lowest <518O value in naturally occurring isotope-fractionation factor between water and CC>2 of terrestrial material is -62.8 %o, found in Antarctic ice 1 O 1.0412 recommended by Friedman and O'Neil (1977). (Aldaz and Deutsch, 1967). The mole fraction of O Thus, 41 than other carbonates, and unaltered carbonatites range others, 1994; Kendall, 1998; Williard and others, in <518O composition between -1.3 %o (Garlick, 1969) 2001). In contrast, 6 18O values of dissolved nitrate in and +7.7 %o (Suwa and others, 1975). However, soils and ground waters range from about -2 %o to altered carbonatites can have <518O values as high as +22 %o (Amberger and Schmidt, 1987; Kendall, 1998; +29 %o (Suwa and others, 1975). Williard and others, 2001). The relatively low values 1 O The range in <518O of non-marine carbonates is reflect incorporation of oxygen depleted in O from much greater than that of marine carbonates because local meteoric water into the nitrate during the oxygen isotopic composition of continental water nitrification (microbial oxidation of ammonium to controls the isotopic content of carbonates and varies nitrate) in soils. substantially (table 6). The lowest 6 1 SiO value Other Oxides Yapp (1987b; 1993) has (-20.5 %o) is found in calcite crystals ablating out of investigated the oxygen and hydrogen isotopic the ice at the Elephant Moraine, Antarctica, and these composition of goethite (FeOOH). At 25 °C, goethite i o low O concentrations are attributed to precipitation is enriched in 18O by 6.1 %o relative to formation of calcite from aqueous solutions discharged by hot water (Yapp, 1990). Yapp finds a substantial springs under the East Antarctic ice sheet (Faure and variation in oxygen isotope fractionation between others, 1988). The carbonate with the highest 18O goethite and water, and proposes that mineral pairs, content found in the literature is from saline deposits such as chert-goethite, might be suitable for of the Pripyat Trough, Belarus, with S 18O values as determining temperatures of formation. The <518O high as +36.4 %0 (Makhnach and others, 1994). values of goethite in Yapp's (1987b; 1993) studies Nitrogen oxides With a greenhouse effect 180 range between -15.5 %o and +4.4 %o. times as strong as that of carbon dioxide on a per Gibbsite [Al(OH)s] is the most common molecule basis, nitrous oxide is an important aluminum-bearing mineral in lateritic bauxites and is greenhouse gas and it is increasing in abundance in formed in tropic and subtropical environments. Bird the atmosphere because of anthropogenic activity. and others (1990) have shown that at 25 °C gibbsite is Nitrous oxide is produced by microbial nitrification enriched in 18O by 16.0 %o relative to the water from and denitrification in soils, the ocean, and other which it formed. This enrichment is in contrast to an aquatic environments, and it is a by-product in the earlier study by Lawrence and Taylor (1972) whose manufacture of nylon. Thiemens and Trogler (1991) results may have been affected by either partial indicate that the release of artificial by-product nitrous dehydroxylation of the gibbsite during out gassing oxide may account for 10 percent of the increase prior to extraction or by the presence of a goethite observed in atmospheric nitrous oxide concentrations. contaminant in the samples (Bird and others, 1989). The <518O value of typical tropospheric nitrous oxide is The <518O of gibbsite in the studies of Bird and others ~ +44 %0 (Wahlen and Yoshinari, 1985; Kirn and (1989) and Bernard (1978) ranged from +5.6 %o to Craig, 1993), whereas the various sources of nitrous +12.0 %o. Boehmite [y-AlO(OH)] also is present in oxide emissions have a wide range of 42 change in <518O over time to differences in the <518O of phillipsite, which they attributed to formation at low sea water that precipitated the phosphorites, but they temperature in isotopic equilibrium with modified sea also attributed some of the change to phosphorite water. formation at higher temperatures in the past. The Sulfates Van Stempvoort and Krouse (1994) lowest <518O value in phosphates was measured on provide a comprehensive review of <518O in sulfate. samples from Montana and Tennessee (Longinelli and Mizutani and Rafter (1969) measured (518O values of Nuti, 1968), both with a value of +8.6 %0. sulfate in precipitation as high as +14.1 %o. Biogenic apatite acquires its isotopic composition Correcting for chloride and sulfate sea-spray addition, through exchange between phosphate and water in they calculate (518O values for the pure atmospheric enzyme-catalyzed reactions, such as the formation of component to be as high as +19.5 %o. Norman and bones and teeth, according to Shemesh and others Krouse (1992) report <518O values of sulfate in air as (1983). Thus, the <518O value of phosphate in bones low as -19 %o and attribute the low 18O and teeth is closely linked to the d 1 RO of ingested concentrations to incorporation of oxygen from 18O water because the temperature of mammals is depleted Canadian atmospheric water vapor in the relatively constant and because biogenic phosphate sulfate. precipitates in oxygen isotopic equilibrium with body The oxygen isotopic composition of sulfate in the water (Longinelli, 1984). Cormie and others (1994) modern ocean is essentially constant both vertically demonstrated a linear relation between the <518O of and horizontally. Longinelli (1989) reported a mean bone phosphate of North American deer and the <5 1 RO 43 Kroopnick and Craig, 1972, by correcting to a CO2- Magnesium A(Mg) = 24.3050(6) tbO isotope-fractionation factor of 1.0412; Friedman and O'Neil, 1977). The <518O of cellulose has been Magnesium is the seventh most abundant element studied since the recognition by Libby and Pandolfi in the cosmos behind hydrogen, helium, oxygen, (1974) that the S18O of cellulose in tree rings is carbon, neon, and nitrogen. Abundant supplies are correlated to the 6 1 8O of leaf water. As a result of the found in the minerals dolomite [CaMg(CO3)2], summation of the isotope fractionation between magnesite (MgCOs), and epsomite (MgSO4-7H2O). carbon dioxide and water (+41 %o), exchange of Magnesium can be produced by electrolysis of fused oxygen in cellulose with that in carbonyl, and direct anhydrous MgCb at 750°C or by the reaction of introduction of water into organic intermediates, the calcined dolomite with FeSi at 1150°C. Magnesium <518O of cellulose is +27 ± 4 96o relative to that of leaf is important as a strong, light metal, having a density water (Sternberg, 1989; Schmidt and others, 2001). about two-thirds that of aluminum. It is used as the The range in S 18O of naturally occurring elemental metal and in alloys. carbohydrates and immediate descendents (cellulose, soluble sugars, and glycerol) is between +19 %o for Reference materials and reporting of isotope cane sugar (Hillaire-Marcel, 1986) and +37.0 %o for ratios cellulose from Bouteloua hirsuta (Sternberg and Although both 25Mg/24Mg and 26Mg/24Mg isotope others, 1984). The data of Schmidt and others (2001) ratios can be measured, 26Mg/24Mg ratios generally are show that natural Furaneol® (<518O = +31.5 ± 1.5 %0) /g\ measured on terrestrial materials and reported as can be distinguished easily from synthetic Furaneol S26Mg values relative to NIST SRM 980 magnesium ( 44 Table 18. Isotopic composition ofNIST SRM 980 magnesium metal [Atomic mass given in unified atomic mass units, u] Isotope Atomic Mass Mole Fraction 24Mg 23.985 041 87(26) 0.789 92(25) 25Mg 24.985 837 00(26) 0.10003(9) 26Mg 25.982 593 00(26) 0.11005(19) From Audi and Wapstra (1993). Calculated from Catanzaro and others (1966) and Rosman and Taylor (1998). Table 19. Magnesium isotopic composition of selected magnesium-bearing materials [Values for Minimum <$26Mg Value Maximum S26Mg Value Substance <526Mg Reference <526Mg Reference MARINE SOURCES Sea water +2.55+-0.12 Chang and +2.55±0.12 Chang and others, 2001b others, 200 Ib Foraminifera -1.95 Chang and +0.85 Chang and others, 200 Ib others, 200 Ib ELEMENTAL -0.12 Chang and +0.12 Chang and MAGNESIUM others, 2001b others, 200 Ib Atomic Weight 24.3040 24.3045 24.3050 24.3055 24.3 Mole Fraction of 26Mg 0.1096 0.1098 0.1100 0.1102 0.1104 STANDARD ATOMIC WEIGHT I MARINE SOURCES Sea water I Foraminifera - i I ELEMENTAL MAGNESIUM SRM 980 l , I , I , l < I , I , I , I , ! , -5 -3-2-10123 526Mg, in %0 relative to SRM 980 Figure 7. Magnesium isotopic composition and atomic weight of selected magnesium-bearing materials. The d2 Mg scale and the 26Mg mole-fraction scale were matched using the data in table 18; therefore, the uncertainty in placement of the atomic-weight scale and the 26,Mg mole-fraction scale relative to the 6 Mg scale is equivalent to ±2.1 %o. 45 spectrometry were indistinguishable (<$26Mg = +2.55 ± IRMM-017 relative to NBS 28 (-1.3 %o) determined 0.12 %o) in isotopic composition and have the highest by T. Ding (unpublished data). 26Mg content found in the literature for a material of Other isotopic reference materials (table 21) natural terrestrial origin. The mole fraction of 26Mg in include: IRMM-017 elemental silicon, IRMM-018 these samples is 0.1103 and^/Mg) = 24.3055. SiO2, NIST SRM 990 elemental silicon, and rose sys- Marine foraminifera were depleted in Mg by 1.7 %o quartz (quartz from the Rose Quartz Pegmatite, a to 4.5 %o relative to sea water, consistent with a quartz and feldspar pegmatite in the Pala district near kinetic isotope fractionation of 1.8 %o to 2.5 %o during San Diego, California, and used as a reference calcite precipitation. The sample with the lowest material by the California Institute of Technology, 26Mg value for a material of natural terrestrial origin is Pasadena, California, USA) (Tilles, 1961; Molini- a foraminifer with a <526Mg value of-1.95 %o (Chang Velsko and others, 1986). The first three have been and others, 200 Ib). The mole fraction of 26Mg in this used primarily for absolute isotope-^abundance sample is 0.1099 and ^r(Mg) = 24.3046. This value measurements. is consistent with the results of a cave study by Galy and others (2000), which indicates that calcite is Ranges in Isotopic Composition depleted in 26Mg relative to water from which it is In natural materials, the valence state of silicon precipitating. always is +4 and the relative mass difference between Elemental magnesium The <526Mg of SRM 980 its isotopes is smaller than those of the elements with elemental magnesium has been analyzed by numerous lower atomic weight. Thus, isotopic variation of workers. However, the analyses of Chang and others silicon isotopes (table 22 and figure 8) is smaller (200Ib) yield the best reproducibility with a 2-o (< 8 %o) than that of most of the elements considered standard deviation of ±0.12 %o. above (hydrogen through magnesium). An anomalous <530Si value of-11.2 %o for a kaolin sample (Ding and others, 1988) is not included in table 22 and figure 8. Silicon A(Si) = 28.0855(3) The most comprehensive document on silicon isotopic variations is that of Ding and others (1996). T hey Behind oxygen, silicon is the second most present silicon isotope distribution graphs based on abundant element in the Earth's crust (Ding and more than 1000 samples. Other compilations of others, 1996). Silicates are the most common silicon- silicon isotope-abundance variations and isotope- bearing compounds, comprising 75 % of crustal rocks fractionation factors include Hoefs (1987) and by weight. Silica, SiO2, is the second most abundant Douthitt (1982). silicon-bearing compound, comprising 12 % of crustal Silicon isotopic equilibrium fractionations are rocks. These two classes of minerals make up 87 % present among silicon-bearing compounds. The Si of the Earth's crust. Silicon is typically made by content of silicates varies with polymerization of the reduction of quartzite or sand with coke in an electric silicon-oxygen tetrahedra, increasing from arc furnace. Silicon is used increasingly in nesosilicates (isolated SiO4 tetrahedra, such as olivine), semiconductors, in alloys, and in polymers. inosilicates (chains of SiO4 tetrahedra, such as enstatite), phyllosilicates (sheets of SiO4 tetrahedra, Reference materials and reporting of isotope such as talc), to tectosilicates (frameworks of Si04 ratios tetrahedra, such as albite), the 30Si content increases. Although both 29Si/28Si and 30Si/28Si isotope However, the magnitude of the isotope fractionation is ratios can be measured, 30Si/28Si ratios generally are small the largest is on the order of 1 %o. Thus, measured on terrestrial materials and reported as <530Si silicon isotope ratio measurements of minerals cannot values relative to NIST NBS 28 pilica sand, which is be used for geothermometry because isotope-ratio assigned a 46 Table 20. Silicon isotopic composition ofNBS 28 silica sand [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 28Si . 27.976 926 49(22) 0.922 223(9) 29Si 28.976 494 68(22) 0.046 853(6) 30Si 29.973 770 18(22) 0.030 924(7) " TT.-^,« A ,,,-]; n ^A Yirn^o4-~n /inm\ 8 Values are based on De Bievre and others (1994) and a <530Si value for IRMM-017 of -1.3 %o relative to NBS 28 silica sand (T. Ding, unpublished data). Table 21. Silicon isotopic composition of selected silicon-bearing isotopic reference materials [Values given in per mill relative to NBS 28 silica sand] 2Q <530Si Reference Material Substance O \j\ Reference SRM990 elemental Si +0.3 +0.5 T. Ding, unpublished data IRMM-017 elemental Si -0.7 -1.3 T. Ding, unpublished data IRMM-018 Si02 0.0 0.0 T. Ding, unpublished data California Institute of SiO2 -0.28 Molini-Velsko and others, Technology rose quartz 1986 clay minerals are enriched in 28Si relative to the relatively few silicon isotope ratios have been solution. determined on these materials, Ding and others Igneous rocks The great majority of silicon (1996) measured more than 90 rocks and minerals isotope ratios in igneous rocks are found in three for silicon isotopic composition. These results studies (Douthitt, 1982; Ding and others, 1988; and indicate that during metamorphism to slates and Ding and others, 1996). Values of <530Si of basalts schists silicon isotope abundances are preserved. The range from -1.0 %o to -0.3 %o (Ding and others, (530Si of slates and schists range from -1.1 %o to 1996). Values of basaltic andesites range from +0.4 %o. The <530Si of plagioclase amphibolites, -0.7 %o to +0.2 %o. The range for gabbros is larger, granulites, leucogranulites, gneisses, migmatites, and from -0.9 %o to +0.3 %o, and may reflect assimilation hornfels range from -0.6 %o to +0.3 %o (Jiang and of crustal rocks. Douthitt (1982) conducted a large others, 1992; Ding and others, 1996), reflecting the investigation of granite rocks. Additional studies by isotopic compositions of their protoliths. Ding and others (1996) lead to the conclusions that Vein quartz and silicified rocks Although not granites are enriched in 30Si relative to mafic igneous large in mass, quartz veins are widespread and are rocks and that <530Si values of granites range from closely related to mineralization. Their <530Si values -0.4 %0 to +0.4 %o, with a mean of about -0.1 %o. range from -1.5 %o to +0.7 %o; however, the majority Granites of different origins show no clear differences of values are in the range -0.9 %o to +0.7 %o (Ding in their silicon isotope ratios (Ding and others, 1996). and others, 1988; Ding and others, 1996). This The igneous rock with the highest 30Si content (<530Si relatively wide range in isotopic composition = +0.4 %o) is a monzonite from Dongping gold mine, suggested to Ding and others (1996) that silicon in Hebei, China (Lu and Wan, 1992). vein quartz has multiple sources or may be Metamorphic rocks Because metamorphic isotopically fractionated during precipitation. That the rocks are a major reservoir of silicon and because mean (530Si of vein quartz is near -0.2 %o suggests that 47 Table 22. Silicon isotopic composition of selected silicon-bearing materials [Values for <530Si given in per mill relative to NBS 28 silica sand] Minimum d 30rSi Value Maximum 48 Atomic Weight 28.0850 28.0852 28.0854 28.0856 28.0858 Mole Fraction of 30Si 0.0308 0.0309 0.0310 0.0311 STANDARD ATOMIC WEIGHT ^ 'IGNEOUS ROCKS METAMORPHIC ROCKS VEIN QUARTZ AND SILICIFIED ROCKS California Institute of Technology rose quartz I I SEDIMENTARY ROCKS IRMM-018 ^NBS28 Quartz sandstones Clay minerals I Sinter Sea-floor hydrothermal siliceous precipitates Other siliceous rocks DISSOLVED SILICA BIOGENIC SILICA IRMM-017 S!RM 990 ELEMENTAL SILICON -6 -4-2024 630Si, in %0 relative to NBS 28 Figure 8. Silicon isotopic composition and atomic weight of selected silicon-bearing materials. The <$30Si scale and 30Si mole-fraction scale were matched using the data in table 20; therefore, the uncertainty in placement of the atomic-weight scale and the 30Si mole-fraction scale relative to the 6 Si scale is equivalent to ±0.23 %o. Springs, Nevada ranges from -1.2 %o to 0.1 %o present in carbonate rocks as trace amounts, thin (Douthitt, 1982). The 49 Dissolved silica is enriched in 30Si relative to igneous <530Si were -1.3 %o, +0.5 %o, and -0.6 %o, respectively rocks because during weathering 28Si is preferentially (T. Ding, unpublished data). concentrated in clay minerals. Douthitt (1982) analyzed the <530Si of hot springs in Yellowstone National Park, Wyoming and Mammoth, California Sulfur A(S) = 32.065(5) (USA), and found a range of-0.4 %0 to +0.1 %o. The <530Si of dissolved silicon from several ocean The average concentration of sulfur in the Earth's basins is +1.1 ± 0.3 %o, and the deep Pacific Ocean is crust is 340 mg/kg (Greenwood and Earnshaw, 1997); depleted in 30Si relative to the Atlantic Ocean by it is the sixteenth element in order of crustal about 0.4 %0 (De La Rocha and others, 2000). The abundance. Important commercial sources of sulfur more positive <530Si values are found in surface waters, include elemental sulfur in salt domes in the United because of preferential incorporation of 28Si in States and Mexico, evaporite deposits in southeastern biogenic opal formation by diatoms. Poland, EbS in natural gas and crude oil, and pyrite Biogenic silica Almost all organisms contain (FeS2) and other metal-sulfide ores (Greenwood and some silicon. Sometimes silicon appears as opal in Earnshaw, 1997). Sulfur commonly is converted into major skeletal structures. Silica-rich organisms sulfuric acid and then into numerous other compounds include tracheophyta, rice husk, bamboo, diatoms, for commercial use. sponges, and radiolaria. The isotopic composition varies greatly from species to species (-3.7 %o to Reference materials and reporting of isotope +2.5 %o). The lowest <530Si value found in the ratios literature (-3.7 %o) for a material of natural terrestrial Although sulfur has 4 stable isotopes (table 23) origin is from biogenic sponge spicules from the Gulf ranging from 32S to 36S, the ratio 34S/32S typically is of California, Mexico (Douthitt, 1982). The mole measured in relative isotope ratio work because these fraction of 30Si in this sample is 0.030 816 and ,4r(Si) are the 2 most abundant isotopes. The historical = 28.085 22. In the literature, the highest 30Si content reference material for relative isotope ratio of biogenic silica is found in a horsetail plant measurements of sulfur isotopes, CDT troilite (FeS) (Equisetum) from California (USA) (Douthitt, 1982). from the Canon Diablo meteorite, varies in <534S by as Ding and others (1996) analyzed the silicon isotope much as 0.4 %o (Beaudoin and others, 1994). abundances in 5 bamboo samples from Beijing, Consequently, an advisory committee of the IAEA Qingdao (Shandon province), and Ningbo (Zhejiang recommended in 1993 that the Ag2S reference province), and found values between -2.2 %o and material IAEA-S-1 (previously known as NZ-1) be +1.8 %o. The <530Si values differed from place to assigned a <534S value of -0.3 %o exactly, thereby place and also within a single bamboo plant. The 30Si establishing a VCDT scale (Vienna CDT, the new concentration increases from the main stem to the primary reference for sulfur isotope ratios having a leaves. Rice plants from Hunan and Jiangsu <534S value of 0 %o). This recommendation was provinces had <530Si values between -1.0 %o and adopted by IUPAC in 1995 (Krouse and Coplen, +1.8 %o (Ding and others, 1996). 1997). The absolute sulfur isotope abundances of De La Rocha and others (1998) found that <530Si IAEA-S-1 and VCDT have been determined (Ding of diatoms varied by about 1 %o in the Southern and others, 2001) and the abundances of VCDT are Ocean over the last glacial cycle. They attribute the listed in table 23. observed <530Si variations to greater production of opal Table 24 lists three silver sulfides, an elemental by diatoms during the interglacials resulting in an sulfur, a zinc sulfide, and three barium sulfates used increase in the 30Si content of the thus further depleted as reference materials. These internationally finite-sized pool of dissolved silica in surface waters distributed secondary sulfur-bearing reference of the Southern Ocean. De La Rocha and others materials are distributed by IAEA and (or) NIST for (1997) demonstrated that the 50 Table 23. Sulfur isotopic composition of a material with 634S = 0 relative to VCDT [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 32S 31.972 070 73(15) 0.950 3957(90) 33S 32.971 458 54(15) 0.007 4865(12) 34S 33.967 866 87(14) 0.041 9719(87) 36g 35.967 080 88(25) 0.000 1459(21) From Audi and Wapstra (1993). B From Ding and others (2001). Table 24. Sulfur isotopic composition of selected sulfur-bearing isotopic reference materials [Values for Reference Material Substance <534S Reference IAEA-S-1 (NZ1) Ag2S -0.3 (exactly) Gonfiantini and others, 1995 IAEA-S-2 (NZ2) Ag2S +22.67 ±0.15 T. Ding, unpublished data IAEA-S-3 Ag2S -32.55 ±0.12 T. Ding, unpublished data Soufre de Lacq S +16.90 ±0.15 H.P. Qi, U.S. Geological Survey, written communication, 2002 NBS 123 ZnS (sphalerite) +17.44 Zhang and Ding, 1989 NBS 127 BaSO4 +21.1 T. B. Coplen, unpublished data IAEA-SO-5 BaSO4 +0.49 ±0.11 T. Ding, unpublished data IAEA-SO-6 BaSO4 -34.05 ± 0.08 T. Ding, unpublished data perhaps the most analytically challenging. 34S/32S isotope scale is expanded. For example, whereas isotope ratios usually are determined on SO2 using NBS 127 BaSO4 was reported by Hut (1987) to have electron impact ionization mass spectrometry and a <534S value of+20.32 %o, T. B. Coplen (unpublished commonly are measured with a l-o standard deviation data) finds a value of+21.1 %o. On a scale in which of ±0.2 %o. However, measurements of sulfur isotopic IAEA-S-1 is assigned <534S = -0.3 %o and IAEA-S-2 reference materials by different laboratories, typically has <534S = +22.67 %o, the value of Soufre de Lacq analyzing SO2 gas, display unacceptably wide elemental sulfur measured by continuous flow isotope variation. Some of this difficulty may be caused by ratio mass spectrometry is +16.96 ± 0.18 %o (H. P. Qi, memory effects in sample preparation and in isotope U.S. Geological Survey, written communication, ratio analysis, or by incorrectly accounting for the 2002), more positive than the value of+16.2 %o oxygen isotopic composition of the SO2 analyzed. To reported by Carmody and Seal (1999). minimize these effects, T. Ding has analyzed sulfur isotopic reference materials (table 24) by converting Ranges in Isotopic Composition sulfur into SF6 instead of SO2, following the strategy The valence of sulfur is -2 to +6 in naturally of Rees (1978). Results indicate that the SF6 sulfur occurring materials. Inorganic sulfur compounds with 51 Atomic Weight 32.060______32.065______32.070______32.075I i i i i | i i ii| i i i i | Mole Fraction of 34S 0.040 0.041 0.042 0.043 0.044 0.045 0.046 0.047 I ' I STANDARD ATOMIC WEIGHT SULFATE ' Atmospheric I Surface water/ground water ^ ^^ ^ Modern ocean I Minerals ^^ -i "" Commercial | Sulfuric acid "T^~* _. . IAEA-SO-6. IAEA-SO-5J. NBS 1Z7 Reagents SULFUR DIOXIDE ' Atmospheric I Reagents h I ELEMENTAL SULFUR 0 , . , ... .. Soufre De Lacq_ Native . " Commerciar ORGANIC SULFUR ' Soil I Vegetation I Animals Fossil fuels Reagents SULFIDE Atmospheric H2S ^ i Thermogenic H2S Surface water/ground water ^"^^"""^"'"^fe Minerals | Reagent H9S ^.. * * . IAEA-S-3.__IAEA-S-1 llAEA-S-2 Other reagents ^-^^ -60 -40 -20 0 20 40 60 80 100 120 140 6S,34 in %0 relative to VCDT Figure 9. Sulfur isotopic composition and atomic weight of selected sulfur-bearing materials. The <5S34 scale and 34S mole-fraction scale were matched using the data in table 23; therefore, the uncertainty in placement of the atomic-weight scale and the 34S mole-fraction scale relative to the <534S scale is equivalent to ±0.2 %o. intermediate valence states (sulfite, thiosulfate, and short lifetimes in natural low temperature polythionates, and others) tend to be found in nature geological and hydrologic systems. In springs in as transitory intermediates during redox reactions and Western Canada, Smejkal and others (1971) found an are thus not readily recoverable. These intermediate intermediate believed to be SO32~ with <534S values species, such as SOs", tend to have low concentrations lower by 7 %o to 12 %o than coexisting SO42~ 52 (~+20 %0). The 53 Organic sulfur Assimilation of sulfate by and others, 1962). Using a S31C\ value of+0.43 %0 bacteria and plants produces organic sulfur with 54 Table 25. Chlorine isotopic composition of a material with S37Cl = 0 relative to SMOC [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 35C1 34.968 852 71(4) 0.757 79(46) 37C1 36.965 902 60(5) 0.242 21(46) A From Audi and Wapstra (1993). " /~"«1^,>1r.<-«J A.~»« V^~ ««. ! ^4-Un../-, /1AA1t,\ OU:,-,U,-, n ~A ^ *-!, ,- /1 f»£T\ and Rosman and Taylor (1998). Table 26. Chlorine isotopic composition of selected chlorine-bearing isotopic reference materials [Values given in per mill relative to SMOC] Reference Material Substance <537C1 Reference SRM975 NaCl +0.43 ± 0.04 Xiao and others, 2002b SRM 975a NaCl +0.2 ± 1.5 NIST, 2001 ISL 354 NaCl +0.05 ± 0.02 Xiao and others, 2002b to ocean water from which they precipitated that the (537C1 of the source of chlorine in crustal (Kaufrnann and others, 1984; Eggenkamp and others, rocks ranges between +3.0 %o and +7.2 %o. _ 0*7 1995). The d Cl of hydrothermal ore deposit fluids is Chloride in ground waters is derived from a near 0 %0; Eastoe and others (1989) found <537C1 of variety of sources including upwelling of brines from fluid inclusions from Mississippi Valley-type deposits lower formations, road salt, and weathering of rock. in Tennessee to range between -1.1 %o and +0.8 %o, Desaulniers and others (1986) point out that at low and attributed isotope fractionation in hydrothermal temperatures dissolved chloride in ground water fluids to high temperature equilibrium isotope usually is not affected by geochemical reactions with exchange. sediments or by biological processes. Thus, diffusion The chlorine content of oceanic crustal rocks is of chloride waters, which should affect the 37C1 and low, but chlorine isotopic composition has been 35C1 distribution when ground-water flow is slow measured in Costa Rica Rift ocean drill holes using (because the diffusion coefficient of 37C1 is smaller positive thermal ionization mass spectrometry than that of 35C1), should be measurable. In a study (Magenheim and others, 1995). Glasses range in of ground waters in Quaternary glacial deposits of c537Cl from +0.2 %o to +7.2 %o, amphibole-bearing southwestern Ontario, Canada, samples from 2 sites whole rocks range from +0.4 %o to +3.4 %o, and ranged in <537C1 from -0.8 %o to +2.2 %o and smectite veins range from +4.0 %o to +7.5 %o. The correlated with chloride concentration. Desaulniers value of +7.5 %o is the most positive found in the and others (1986) concluded that the isotopic literature for a material of natural terrestrial origin. enrichment in 35C1 down gradient resulted from For this sample the mole fraction of 37C1 is 0.243 56 upward diffusion of saline formation waters over a and A(C1) = 35.4553. Magenheim and others (1995) period of about 15,000 years. "\1Although Canadian conclude that Cl isotopes of smectite and amphibole Shield ground waters vary in 8 Cl value between samples are fractionated when sea water 37C1 is -0.51 %o and +0.17 %o (Frape and others, 1995), the preferentially incorporated into altered oceanic crust range of Fennoscandian ground waters is much because of the stronger bond of 37C1. They conclude greater, -0.61 %o to +1.97 %o (Frape and others, 55 Table 27. Chlorine isotopic composition of selected chlorine-bearing materials [Values for <537C1 given in per mill relative to SMOC (Standard Mean Ocean Chloride)] Minimum S37C\ Value Maximum 1995). The highest <537C1 value (+2.94 %0) is reported chlorinated solvents including perchloroethylene for a hot-spring water (oil-field water) from Daqaidam (PCE), trichloroethylene (TCE), and 1,1,1 in the Qaidam Basin, China (Liu and others, 1997). trichloroethane (TCA), supplied by different Large <537C1 variations (-4.3 %0 to -1.2 %o) are manufacturers and found a range in S31C\ of -2.5 %o observed in oil formation waters from the North Sea to +4.4 %o. Both noted that 37C1 content was Forties Field (Eggenkamp and Coleman, 1993; dependent upon manufacturing process. Each Eggenkamp, 1994). The concentrated brine of the solvent analyzed had a <537C1 value that differed basin center probably was overpressured and its very between manufacturers. Differences were found in negative <537C1 values resulted either from the S13C values of the solvents. Therefore, it was ultrafiltration or diffusion during cross-formational concluded that <513C and <537C1 measurements might flow (Eggenkamp, 1994). Pore water from the be useful for identifying sources of chlorinated Nankai subduction zone has the lowest <537C1 value solvent plumes in ground water. In 1999, Beneteau (-7.7 %o) found in the literature for a material of and others analyzed PCE, TCE, and TCA from a natural terrestrial origin (Ransom and others, 1995). new solvent batch from PPG Industries and Dow The mole fraction of 37C1 in this sample is 0.240 77 Chemicals to compare S13C and <537C1 values with and ^r(Cl) = 35.4497. This low value is attributed to those previously measured. Results indicate that the formation of clays that preferentially incorporate 37C1 <513C and the <537C1 of TCA do not remain consistent into their structure, enriching pore water in 35C1. from batch to batch (Beneteau and others, 1999)."^7 Organic solvents Aravena and others (1996) However, there is a consistent and substantial 6 Cl and van Warmerdam and others (1995) analyzed difference between PCE from PPG Industries and 56 Atomic Weight 35.449 35.450 35.451 35.452 35.453 35.454 35.455 35.456 Mole Fraction of 37CI 0.2405 0.2410 0.2415 0.2420, 0.2425 0.2430 0.2435 STANDARD ATOMIC WEIGHT CHLORIDES Sea water SMOC. Ground, surface, pore, and oil formation waters Hydrothermal fluid-inclusion waters SRM 975 NaCI (halite) ISL 354 KCI (sylvite) Rock or sediments ORGANIC SOLVENTS CH3CI Other (trichloroethylene, and others) -8 -6 -2 0 5°'CI,.37 in %0 relative to SMOG Figure 10. Chlorine isotopic composition and atomic weight of selected chlorine-bearing materials. The <537C1 scale and the 37C1 mole-fraction scale were matched using the data in table 25; therefore, the uncertainty in placement of the atomic-weight scale and the 37C1 mole-fraction scale relative to the <537C1 scale is equivalent to ±2.5 %o. DOW Chemicals that could allow the use of 13C/12C a chemical scavenger in the steel industry to remove in conjunction with 37C1/35C1 ratios for fingerprinting oxygen, sulfur, and phosphorus. applications. Jendrzejewski and others (2001) analyzed chlorinated hydrocarbons for carbon and Reference materials and reporting of isotope chlorine isotopic content and came to the same ratios conclusion. Chlorinated solvents increasingly are Because the two isotopes 40Ca and ^Ca are the being found in ground waters and it should not be most abundant of calcium's six isotopes (table 28), surprising if the extreme values in table 27 are 44Ca/40Ca ratios are measured and expressed as exceeded in the future. The <537C1 of commercial values relative to a variety of materials, depending methyl chloride ranges from -6.0 %o (Tanaka and upon the author. The Berkeley Center for Isotope Rye, 1991) to +4.0 %o (Jendrzejewski and others, Geochemistry (Berkeley, California) reports ^Ca 2001). values relative to a high purity calcium carbonate laboratory reference material (Skulan and others, 1997). Scripps Institution of Oceanography (San Calcium A(Ca) = 40.078(4) Diego, California) reports tf^Ca values relative to sea water (Zhu and Macdougall, 1998). The University Calcium is the fifth most abundant element in the of Oxford expresses ^Ca values relative to NBS Earth's crust. Pure calcium is prepared by electrolysis 915a calcium carbonate (Halicz and others, 1999). of fused CaC\2. Elemental calcium is used in alloys, Russell and others (1978) reported ^Ca/^Ca isotope especially with aluminum, and it is used in the ratio measurements relative to reagent calcium purification of chromium, zirconium, thorium, fluoride. 44Ca/40Ca isotope ratio measurements can be uranium, and rare earth elements. Calcium is used as performed using positive ion thermal ionization mass 57 Table 28. Calcium isotopic composition ofNIST SRM 915a calcium carbonate [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 40Ca 39.962 5912(3) 0.969 41(6) 42Ca 41.958 6183(4) 0.006 47(3) 43Ca 42.958 7668(5) 0.001 35(2) "Ca 43.9554811(9) 0.020 86(4) 46Ca 45.953 6927(25) 0.000 04(1) 48Ca 47.952 533(4) 0.001 87(1) A From Audi and Wapstra (1993). B Calculated from Moore and Machlan (1972) and the determination by D. J. DePaolo (University of California, Berkeley, California, written communication, 2001) that NBS 915a is depleted in ^Ca relative to NBS 915 by 0.17 %o. spectrometry. ^Ca/^Ca isotope ratios have been adjusted in this report by adding +1.89 %o because the made with multiple collector inductively coupled ^Ca of Scripps sea water, which is used as their plasma mass spectrometry (Halicz and others, 1999) reference zero value, is +0.92 %o relative to the and isotope ratios can be determined with a l-o Berkeley calcium carbonate reference material (Skulan standard deviation of ±0.1 %o. and others, 1997). It is not completely clear how to The absolute isotope abundances of SRM 915 adjust the 40Ca/44Ca isotope ratio measurements of calcium carbonate were determined by Moore and Russell and others (1978) because their measurement Machlan (1972). Although SRM 915 is no longer of sea water suggests an adjustment of between distributed by NIST, D. J. DePaolo (University of 0.77 %o and 1 %o, whereas their analysis of an California, Berkeley, California, written Atlantic Ridge tholeiite suggests an adjustment of communication, 2001) has measured the ^Ca of 0.67 %o. We have compromised and adjusted their SRM 915 and of SRM 915a, which has replaced it. values upward by 0.8 %o. Based on 2 mass spectrometric analyses, the ^Ca of Igneous rocks The ^Ca values of igneous SRM 915 is -0.80 ± 0.23 %o relative to the Berkeley rocks fall in a small range (+0.7 %o to +1.35 %o) calcium carbonate. The value for SRM 915a is -0.97 based on measurements by Skulan and others (1997), ± 0.20 %o also based on 2 analyses. Values of ^Ca who analyzed basalts, dacites, and a rhyolite, and are expressed relative to SRM 915a in this report based on measurements by Zhu and Macdougall because SRM 915a is an internationally distributed (1998) of three mid-ocean ridge basalt (MORE) reference material. The absolute calcium isotope samples. This range may be too large because of abundances of SRM 915a are given in table 28. analytical difficulties as other evidence indicates that igneous rocks should be relatively homogeneous in Ranges in Isotopic Composition calcium isotopic composition (Zhu and Macdougall, Calcium is found in naturally occurring materials 1998). The ^Ca values of three MORE samples only in the +2 valence state. Consequently, the range ranged between +1.20 %o and +1.35 %o (Zhu and in calcium isotopic composition found in the literature Macdougall, 1998). is less than 5 %o (table 29 and figure 11). Whereas Carbonates Based on calcium isotope ratio laboratories have expressed their calcium isotope measurements by Russell and others (1978), Zhu and ratios relative to different materials, ^Ca values are Macdougall (1998), De La Rocha and DePaolo reported relative to the NIST SRM 915a scale in this (2000), and D. J. DePaolo (University of California, report. The Berkeley ^Ca data are adjusted in this Berkeley, California, written communication, 2001), report by adding +0.97 %o. The Scripps data are the ^Ca of dissolved carbonate in sea water is 58 Table 29. Calcium isotopic composition of selected calcium-bearing materials [Values for c^Ca given in per mill relative to SRM 915a calcium carbonate] Minimum ^4Ca Value Maximum Value Substance Reference Reference IGNEOUS ROCKS +0.70 Skulan and others, +1.35 Zhuand 1997 Macdougall, 1998 DISSOLVED CALCIUM Sea water +1.7 Russell and others, +2.00 De La Rocha and 1978 DePaolo, 2000 Rivers -0.18 Zhuand +1.26 Zhu and Macdougall, 1998 Macdougall, 1998 CARBONATES Foraminifera, marine ooze, -0.75 Zhu and +2.7 Russell and others, and calcium carbonate Macdougall, 1998 1978 Reagent calcium carbonate -12 Russell and others, +0.97 Skulan and others, 1978 1997 PLANTS AND ANIMALS -2.17 Skulan and +2.76 Skulan and DePaolo, 1999 DePaolo, 1999 ELEMENTAL CALCIUM -6.0 Russell and others, -6.0 Russell and others, 1978 1978 relatively uniform and ranges from +1.77 %o to calcium metal, which involves an evaporation- +2.00 %o. Biologically induced calcium isotope distillation process. fractionation in the fixation of calcium affects the Plants and animals In a survey of numerous distribution of calcium isotopes in the terrestrial materials, Skulan and DePaolo (1999) found that calcium cycle. As dissolved calcium in sea water is calcium from bone and shell is depleted in ^Ca incorporated into foraminifera, 40Ca is preferentially relative to calcium of soft tissue from the same fixed, increasing the ^Ca of sea water. Thus, the organism and relative to source (dietary) calcium. ^Ca of most biological samples is lower than that of Platzner and Degani (1990) found that the t^Ca sea water. Nagler and others (2000) grew the values of pollen and seeds of date palm trees were foraminifera species G. sacculifer in sea water at about 0.6 %o more negative than those of leaves and constant temperature and determined a variation in pulp of these trees. Bullen (U.S. Geological Survey, ^Ca with temperature of 0.24 ± 0.02 %0 per °C; thus, written communication, 2002) finds that tS^Ca values calcium isotope-isotope variation is potentially a new of spruce tree samples range between -1.0 %o and tool for determining past sea surface temperatures. +1.36 %o. The lowest ^Ca value of a naturally The highest ^Ca content (^Ca = +2.7 %o) found in occurring terrestrial material (-2.17 %o) is found in calcium carbonate is found in thinolite (Russell and cougar bone (Skulan and DePaolo, 1999). The mole others, 1978), a calcium carbonate tufa deposit in fraction of ^Ca in this sample is 0.020 82 and ^r(Ca) northwest Nevada. = 40.0778. The highest t^Ca value (+2.76 %o) in a Russell and others (1978) analyzed the calcium material of natural terrestrial origin is found in egg isotopic composition of reagent carbonates and found white (Skulan and DePaolo, 1999). The mole fraction a range from -12 %o to +1.5 %o. The sample with a of **Ca in this sample is 0.020 92 and ^r(Ca) = value of-12 %o was prepared from elemental 40.0784. 59 Atomic Weight 40.074 40.076 40.078 40.080 40.082 Mole Fraction of 44Ca 0.0202 0.0204 0.0206 0.0208 0.0210 0.0212 0.0214 STANDARD ATOMIC WEIGHT IGNEOUS ROCKS DISSOLVED CALCIUM Sea water Rivers CARBONATES Foraminifera, marine ooze, and calcium carbonate SRM915 Reagent calcium carbonate SRM915a PLANTS AND ANIMALS ELEMENTAL CALCIUM -30 -20 -10 0 10 20 30 644Ca, in %0 relative to NBS 915a Figure 11. Calcium isotopic composition and atomic weight of selected calcium-bearing materials. The scale and the 44Ca mole-fraction scale were matched using the data in table 28; therefore, the uncertainty in placement of the atomic-weight scale and the ^Ca mole-fraction scale relative to the ^Ca scale is equivalent to ±2%o. Elemental calcium Russell and others (1978) ratio measurements can be performed using positive report a S^Ca value of -6.0 %o for a sample of ion thermal ionization mass spectrometry, and isotope elemental calcium metal. They point out that one ratios can be determined with a 1-a standard deviation method for the preparation of elemental calcium of approximately ±0.1 %o. The absolute isotope involves an evaporation-distillation process, which abundances of chromium in SRM 979 chromium causes substantial fractionation of calcium isotopes. nitrate was measured by Shields and others (1966) and is listed in table 30. Chromium A(Cr) = 51.9961(6) Ranges in Isotopic Composition Chromium is expected to show isotope The average concentration of chromium in the fractionation because there is substantial relative mass Earth's crust is 122 mg/kg (Greenwood and Earnshaw, difference between its four isotopes (table 30) and 1997). The primary ore of chromium is chromite because it is found in both +6 and +3 oxidation states (FeCr2O4). The principal uses of chromium are in the in the lithosphere. Relatively few chromium isotopic production of non-ferrous alloys and anti-corrosion measurements have been performed. Previous work chromium plating. by Ball (1996) is not included in this report because there may have been analytical problems during Reference materials and reporting of isotope isotopic measurements (T. Bullen, U.S. Geological ratios Survey, oral communication, 2001). For example, Because the isotopes 52Cr and 53Cr are the most Ball found that the 53Cr/52Cr ratio of SRM 979 abundant (table 30), 53Cr/52Cr ratios usually are chromium nitrate changed by 3.3 %o by application of measured and expressed as S5 Cr values relative to his purification methods, suggesting that the sample NIST SRM 979 chromium nitrate. 53Cr/52Cr isotope preparation may not have been quantitative. Other 60 Table 30. Chromium isotopic composition ofNISTSRM979 chromium nitrate [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 50Cr 49.946 0495(14) 0.043452(85) 52Cr 51.9405115(15) 0.837895(117) 53Cr 52.940 6534(15) 0.095006(110) 54Cr 53.938 8846(15) 0.023 647(48) A From Audi and Wapstra (1993). 8 From Rosman and Taylor (1998) and Shields and others (1966). Table 31. Chromium isotopic composition of selected chromium-bearing materials [Values for (553Cr given in per mill relative to SRM 979 chromium nitrate] .53. Minimum d53, Cr Value Maximum d Cr Value Substance 61 Atomic Weight 51.995 51.996 51.997 51.998 Mole Fraction of 53Cr 0.0948 0.0950 0.0952 0.0954 0.0956 I I STANDARD ATOMIC WEIGHT CHROMIUM (VI) I K2Cr2O7 l~ Ground water I CHROMIUM (III) I Cr(N03)3 I SRM 979 I , I , I , I , I , I -4 -20246 653Cr, in %0 relative to SRM 979 Figure 12. Chromium isotopic composition and atomic weight of selected chromium-bearing materials. The <553Cr scale and the 53Cr mole-fraction scale were matched using the data in table 30; therefore, the uncertainty in placement of the atomic-weight scale and the 53Cr mole-fraction scale relative to the <553Cr scale is equivalent to ±1.2 %o. error (±0.2 %0), and SRM 979 has the lowest 53Cr Ranges in Isotopic Composition content found in the literature. The mole fraction of Iron can act as an electron acceptor under 53Cr in SRM 979 (<553Cr = 0 %) is 0.095 01 and anaerobic conditions and as an electron donor under AT(Cr) = 51.9961. both anaerobic and aerobic conditions. Thus, there is the potential for kinetic fractionation of iron isotopes during metabolic reactions. A recent summary of Iron (Ferrum) A(Fe) = 55.845(2) isotope abundance variations of iron in natural materials and a discussion of iron isotope fractionation After oxygen, silicon, and aluminum, iron is the is given in Anbar (2001). Theoretical equilibrium fourth most abundant element in crustal rocks. The 56Fe/54Fe fractionations at 25 °C among iron-bearing major ores of iron include hematite (T^Os), magnetite aqueous complexes are as large as 14 %o (Schauble (FesO4), limonite (2Fe2O3-3H2O), and siderite and others, 2001). (FeCOs). Its primary use is in steel (with up to 1.7 % The variation in isotopic composition of iron- carbon) and in stainless steel (with nickel and other bearing materials is shown in table 33 and figure 13. metals). For comparative purposes, the high purity J-M iron used as a reference material by Beard and Johnson Reference materials and reporting of isotope (1999) and Beard and others (1999) is assumed to be ratios identical in isotopic composition to the high purity Relative iron isotope ratios (56Fe/54Fe) can be elemental iron reference material IRMM-014 used by expressed relative to IRMM-014 elemental iron, other workers; this assumption also was made by which is assigned a <556Fe value of 0 %o. 56Fe/54Fe Anbar (2001). No isotopic results of Dixon and isotope ratio measurements have been performed others (1992) are included in this report because they using thermal ionization mass spectrometry and using contain internal inconsistencies among the isotope multiple collector inductively coupled plasma mass ratios according to Beard and Johnson (1999). spectrometry; isotope ratios can be determined with a The 57Fe/56Fe ratio of ground water from a toxic l-o standard deviation of ±0.15 %o. The absolute waste site in South Carolina (USA) (JP-4 fuel spill) in isotope abundances of IRMM-014 elemental iron are a microbially mediated anaerobic zone was about 0.5 shown in table 32. percent greater than 57Fe/56Fe of 0.5N HC1 leachates 62 Table 32. Isotopic composition ofIRMM-014 elemental iron [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 54Fe 53.939 6147(14) 0.058 45(23) 56Fe 55.9349418(15) 0.917 54(24) 57Fe 56.935 3983(15) 0.021 191(65) 58Fe 57.933 2801(15) 0.002 819(27) A From Audi and Wapstra (1993). B From Rosman and Taylor (1998) and Taylor and others (1992). Table 33. Iron isotopic composition of selected iron-bearing materials [Values for Minimum <556Fe Value Maximum <556Fe Value Substance <556Fe Reference <556Fe Reference IGNEOUS ROCKS -0.8 Berger and von +0.15 Beard and Blanckenburg Johnson, 1999 (2001 SEDIMENTARY ROCKS Fe-Mn oxides -1.62 Beard and +0.17 Beard and others, 1999 Johnson, 1999 Banded iron formations -0.34 Beard and +1.36 Beard and Johnson, 1999 Johnson, 1999 Fe in dolomite -2.54 Bau and others, -0.87 Bau and others, 2001 2001 Fe oxyhydroxide -2.02 Bullen and +0.11 Bullen and others, 2001 others, 2001 NON-MARINE SOURCES Ground water -2.20 Bullen and -0.74 Bullen and others, 2001 others, 2001 PLANTS AND ANIMALS -2.9 Walczyk, 2001 -2.5 Walczyk, 2001 ELEMENTAL IRON -0.04 Zhu and others, +0.04 Zhu and others, 2000b 2000b of aquifer sediment and was substantially greater than fractionated by as much as 1 %o during leaching of 57Fe/56Fe of ground water from the upgradient aerobic hornblende by Anthrobacter or Streptomyces. zone (Bullen and McMahon, 1997). Brantley and Nonbiological fractionation of iron isotopes can also others (2001) have shown that iron isotopes are be large. Anbar and others (2000) observed a 63 Atomic Weight 55.843 55.844 55.845 55.846 55.847 Mole Fraction of 56 Fe 0.9170 0.9172 0.9174 0.9176 0.9178 0.9180 I ' I ' I .' I ' I ' I STANDARD ATOMIC WEIGHT J V flGNEOUS ROCKS -1 1 I SEDIMENTARY ROCKS I Fe-Mn oxides Banded iron formations Fe in dolomite __ I Fe oxy hydroxide I NON-MARINE SOURCES __ I Ground water I PLANTS AND ANIMALS I IRMM-014 ' ELEMENTAL IRON I , , I , , I , , I , , I , , I , , I , , I , , I , i 1 , , 1 -15 -12 -9 -6 -3 0 12 15 6 56ODFe, in %0 relative to IRMM-014 Figure 13. Iron isotopic composition and atomic weight of selected iron-bearing materials. The S Fe scale and the 56Fe mole-fraction scale were matched using the data in table 32; therefore, the uncertainty in placement of the atomic-weight scale and the 56Fe mole-fraction scale relative to the <556Fe scale is equivalent to ±4.3 %o. maximum isotope fractionation of 6 %o during elution <556Fe values between -0.77 %o and -0.13 %0. They of iron in HC1 media from anion exchange columns. found an excellent correlation with lead isotope Anbar and others (2000) proposed that this isotope abundances and concluded that <556Fe variations reflect fractionation is an equilibrium isotope fractionation changes in iron input from terrigenous sources; they between dissolved FeCLf, which is a tetrahedral attributed none of the variation to biologically induced complex, and Fe chloro-aquo complexes (for example, mass fractionation. The <556Fe of oceanic Fe-Mn FeCl2(H2O)4+, which is an octahedral complex). nodules analyzed by Beard and others (1999) ranged Therefore, differences in bonding energy may explain from -1.62 %o to -0.96 %o; those analyzed by Beard isotope fractionations. and Johnson (1999) ranged between -1.36 %o and Igneous rocks Beard and Johnson (1999) and -0.81 %o. A freshwater nodule from Green Bay Lake, Beard and others (1999) conclude that the iron Michigan was enriched in 56Fe with a <556Fe value of isotopic variation of igneous rocks is relatively small +0.17 %o (Beard and Johnson, 1999). Polizzotto and (<556Fe < 0.3 %o). Zhu and others (2001) find that others (2000) report 64 dark layer to +1.36 %o for a light layer (Beard and source of copper is CuFeSz (chalcopyrite). The others, 1999). The sample with a <$56Fe value of primary use of copper is in electrical wires, but +1.36 %o has the highest 56Fe content found in the coinage and copper alloys, such as brass, are literature for a naturally occurring terrestrial substance. important copper-bearing products. The mole fraction of 56Fe in this sample is 0.917 60 and ^4r(Fe) = 55.845 32. An Archean banded iron Reference materials and reporting of isotope formation had a much smaller range of <556Fe values ratios (0 %o for a black layer to +0.35 %o for a red layer). Copper isotope ratios (65Cu/63Cu) are reported The iron in dolomite associated with the banded iron relative to the primary reference NIST SRM 976 formation in the Hamersley Group, Western Australia, elemental copper, with an assigned S?5Cu value of is substantially depleted in 56Fe and <556Fe ranges from 0 %o. Copper isotope ratio measurements have been -2.54 %o to -0.87 %0 (Bau and others, 2001). performed by positive ion thermal ionization mass Field (Mount Ruapehu in Tongariro National spectrometry and by multiple collector inductively Park, New Zealand) and laboratory studies by Bullen coupled plasma mass spectrometry; isotope ratios, and others (2001) indicate that the mineral using the latter, can be determined with a 1-a standard ferrihydrite, formed as a result of abiotic oxidation of deviation of better than ±0.05 %o. The absolute aqueous ferrous iron, contains ferric iron that is isotope abundances of SRM 976 elemental copper enriched in 56Fe relative to coexisting aqueous iron. have been determined by Shields and others (1964) As iron in solution is consumed and the (556Fe of and are listed in table 34. dissolved iron increases, the <556Fe of ferrihydrite increases from -2.02 %o to +0.11 %o because the Ranges in Isotopic Composition formation of ferrihydrite at pH > 5 is essentially The first survey of copper isotopic variation in irreversible. natural materials was that of Walker and others Non-marine sources Dissolved iron in ground (1958), who found a range of more than 12 %o (table water from Mount Ruapehu in Tongariro National 35 and figure 14). These observations were Park, New Zealand, has 65 Table 34. Isotopic composition of SRM 976 elemental copper [Atomic mass given in unified atomic mass units, u] Isotope Atomic Mass Mole Fraction 63Cu 62.929 6007(15) 0.691 74(20) 65Cu 64.927 7938(19) 0.308 26(20) A From Audi and Wapstra (1993). B From Rosman and Taylor (1998) and Shields and others (1964). Table 35. Copper isotopic composition of selected copper-bearing materials [Values for ^5Cu given in per mill relative to NIST SRM 976 elemental copper] Minimum S65Cu Value Maximum S65Cu Value Substance S65Cu Reference S65Cu Reference CARBONATES -1 Shields and +9 Shields and others, 1965 others, 1965 CHLORIDES -7.65 Gale and others, -1.6 Shields and 1999 others, 1965 OXIDES -0.7 Shields and +5 Shields and others, 1965 others, 1965 SULFATES -0.7 Shields and +3.6 Shields and others, 1965 others, 1965 SULFIDES CuFeS2 (chalcopyrite) -1.4 Shields and +5.74 Marechal and others, 1965 others, 1999 CusFeS4 (bornite) -3.2 Shields and +2.4 Shields and others, 1965 others, 1965 Cii2S (chalcocite) -3.3 Shields and +6 Shields and others, 1965 others, 1965 Other -4.5 Walker and +2.7 Walker and others, 1958 others, 1958 NATIVE COPPER -3.03 Marechal and +2 Shields and others, 1999 others, 1965 ARCHAEOLOGICAL -4.30 Gale and others, -0.22 Gale and others, COPPER INGOTS 1999 1999 PLANTS AND ANIMALS +0.08 Marechal and +1.8 Walker and others, 1999 others, 1958 66 Atomic Weight 63.542 63.544 63.546 63.548 63.550 Mole Fraction of 65Cu 0.307 0.308 0.309 0.310 STANDARD ATOMIC WEIGHT CARBONATES CHLORIDES OXIDES SULFATES SULFIDES CuFeS2 (chalcopyrite) Cu5FeS4 (bornite) Cu2S (chalcocite) Other SRM 976 NATIVE COPPER ARCHAEOLOGICAL COPPER INGOTS PLANTS AND ANIMALS -8 -4048 12 665Cu, in %0 relative to SRM 976 Figure 14. Copper isotopic composition and atomic weight of selected copper-bearing materials. The ^5Cu scale and the 65Cu mole-fraction scale were matched using the data in table 34; therefore, uncertainty in placement of the atomic-weight scale and the 65Cu mole-fraction scale relative to the <565Cu scale is equivalent to ±0.9 %o. -7.65 %o, the lowest 65,Cu content found in the Sulfides Shields and others (1965) analyzed 17 literature for a material of natural terrestrial origin, the chalcopyrite (CuFeS2), 9 bornite (Cu5FeS4), 20 mole fraction of 65Cu is 0.3066 and ^r(Cu) = 63.542. chalcocite (Cu2S), and a few other copper sulfide Oxides Shields and others (1965) analyzed 15 samples. Marechal and others (1999) analyzed 3 copper oxides. They ranged in ^5Cu from -0.7 %o chalcopyrite samples by multiple collector plasma for cuprite (CuO) from Bisbee, Arizona (USA), to source mass spectrometry. Zhu and others (2000a) -5.0 %o for cuprite from Demidoff, Ukraine (table 35 analyzed the copper isotopic composition of and figure 14). chalcopyrite from marine black smoker sulfide Sulfates Shields and others (1965) analyzed 7 deposits (hydrothermal systems) and found (f5Cu sulfates for copper isotopic composition. The ^5Cu values ranging from -0.45 %o to +1.17 %o. They of these samples ranged from -0.7 %o for brochantite concluded that 0 Cu values reflect mass fractionation [CuSO4-3Cu(OH)2] from Chuquicamata, Chile, to at low temperature rather than heterogeneity in the +3.6 %o for brochantite from Morenci, Arizona (USA) source. The ranges in <565Cu in sulfides are shown in (table 35 and figure 14). table 35 and figure 14. 67 Native copper More than 15 isotope ratio Zinc A(Zn) = 65.409(4) analyses of native copper are reported in the literature (Walker and others, 1958; Shields and others, 1965; The average concentration of zinc in the Earth's Marechal and others, 1999; Zhu and others, 2000a). crust (76 mg/kg) is slightly greater than that of copper The ^5Cu values of native copper range from (Greenwood and Earnshaw, 1997). The major ores of -3.03 %o from Ray, Arizona (USA) (Marechal and zinc are ZnS (known as zinc blende in Europe and others, 1999) to +2 %0 from Pima, Arizona (USA) sphalerite in the United States) and ZnCOs (known as (Shields and others, 1965). calamine in Europe and smithsonite in the United Archaeological copper ingots Gale and others States). The primary use of zinc is in anti-corrosion (1999) showed that fire refining does not alter the coatings. The standard atomic weight of zinc was isotopic composition of copper. They analyzed 8 changed by CAWIA from 65.39(2) to 65.409(4) in Late-Bronze Age copper oxhide ingots from sites in July 2001, based on the calibrated measurement by Cyprus, Crete, and Sardinia, and found a range in Chang and others (200la). (^Cu from -4.30 %o to -0.22 %o. They concluded that copper isotope ratios can make a contribution to Reference materials and reporting of isotope identifying provenance of archaeological objects made ratios of copper based alloys. Three ingots from Crete There are no internationally distributed isotopic differ in cf5Cu by 2.8 %o and do not match the reference materials for zinc. In their survey of zinc isotopic composition of any copper deposits so far isotope ratios, Marechal and others (1999) reported analyzed in the Mediterranean region, including 66Zn/64Zn ratios and expressed their results as ^6Zn Cyprus and Turkey. values expressed in per mill relative to JMC (Johnson Plants and animals Walker and others (1958) Matthey) 3-0749 L solution. Zinc isotope ratio analyzed marine seaweed (+1.8 %o), organic measurements have been performed using positive ion concentrate from shale (0 %o), and oak tree leaves thermal ionization mass spectrometry and multiple (+0.9 %o). Two marine sediments analyzed by collector inductively coupled plasma mass Walker and others (1958) differed greatly in ^Cu, spectrometry. Using the latter technique, isotope +0.5 %o and +8.1 %o; these values are not shown in ratios can be determined with a l-o standard deviation table 35 or figure 14 because the specific compound of better than ±0.05 %o. The absolute isotope analyzed by Walker is not listed. Marechal and abundances of zinc have been determined by Rosman others (1999) analyzed mussel (+0.08 %o) and human (1972) and are reported in table 36. blood (+0.30 %o). These ranges are shown in table 35 and figure 14. Ranges in Isotopic Composition The advent of multiple collector plasma source mass spectrometry (Walder and Freedman, 1992) has improved the analytical precision of the isotopic Table 36. Isotopic composition of a naturally occurring sample of zinc [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 "Zn 63.929 1461(18) 0.4863(20) 66Zn 65.926 0364(17) 0.2790(9) 67Zn 66.927 1305(17) 0.0410(4) 68Zn 67.924 8473(17) 0.1875(17) 70Zn 69.925 325(4) 0.0062(1) A From Audi and Wapstra (1993). B From Rosman and Taylor (1998) and Rosman (1972). 68 analysis of zinc (Marechal and others, 1999). The full requires less than 500 nanograms of selenium per range in naturally occurring materials is about 1 %o analysis. Solutions containing ~1 mg/kg selenium (Marechal and others, 1999). The material with the have been successfully analyzed by inductively lowest Zn content is ZnS from the Lau Basin, coupled plasma isotope ratio mass spectrometry Pacific Ocean, with a Table 37. Selenium isotopic composition of a naturally occurring material [Atomic mass given in unified atomic mass units, u] Isotope Atomic Mass Mole Fraction 74Se 73.922 4767(16) 0.008 89(3>|- 76Se 75.919 2143(16) 0.093 66(18) 77Se 76.919 9148(16) 0.076 35(10) 78Se 77.917 3097(16) 0.237 72(20) 80Se 79.916 5221(20) 0.496 07(17) 82Se 81.916 7003(22) 0.087 31(10) From Audi and Wapstra (1993). From Rosman and Taylor (1998) and Wachsmann and Heumann (1989). 69 Johnson and others (2000) find that 80Se/76Se is lower Reference materials and reporting of isotope by about 2 %o in total sediment extracts relative to ratios that of the local bay water. The magnitude of this Siebert and others (200la) have measured the isotope fractionation is smaller than that expected for isotopic composition of a number of samples using reduction of Se(VI) or Se(IV) to Se(0), and this multiple collector magnetic sector inductively coupled suggests that reduction of soluble selenium in plasma mass spectrometry (MC-ICP-MS) using a overlying waters is not the primary process by which molybdenum double spike. Isotope fractionations are selenium is incorporated into sediments. In addition, determined on 4 molybdenum isotopes, providing an variable isotopic differences between riverine and internal consistency check. The 2-a external refinery inputs were observed; thus, tracing of refinery reproducibility on 98Mo/95Mo ratios is 0.06 %o. Anbar inputs with selenium isotope ratios is not possible in and others (2001) using (MC-ICP-MS) and either a this particular system (Johnson and others, 2000). zirconium or ruthenium spike are able to analyze samples as small as 1 ug of molybdenum, giving a 2-a precision in 97Mo/95Mo of 0.2 %o. Although there are no internationally distributed isotopic reference Molybdenum A(Mo) = 95.94(2) materials for molybdenum, Siebert and others (200 Ib) determined that ocean water is constant in 98Mo/95Mo The average concentration of molybdenum in the within ±0.1 %o and they recommend expressing Earth's lithosphere is about 1 mg/kg. Molybdenum is 98Mo/95Mo ratios relative to molybdenum dissolved in refined from molybdenite (MoSi), the largest ore ocean water, which is assigned a <598Mo value of 0 %o. deposit of which is found in Colorado, and is obtained Although absolute isotope-abundance determinations as a byproduct from copper production. The primary have been made on naturally occurring molybdenum use of molybdenum is in stainless steel and high ore concentrates (see table 38; Moore and others, speed steel tools. The standard atomic weight of 1974), absolute isotope-abundance determinations molybdenum was changed by CAWIA from 95.94(1) have not been made for any specimen used in relative to 95.94(2) in July, 2001, based on data from Wieser abundance investigations. and de Laeter (2000), which lead to an increase in uncertainty as required by guidelines used by Ranges in Isotopic Composition CAWIA. The advent of multiple collector plasma source mass spectrometry (Walder and Freedman, 1992) has improved the analytical precision of the isotopic Table 38. Molybdenum isotopic composition O/SRM333 molybdenum ore concentrate [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 92Mo 91.906 810(4) 0.148 362(148) 94Mo 93.905 0867(20) 0.092 466(92) 95Mo 94.905 8406(20) 0.159 201(159) 96Mo 95.904 6780(20) 0.166 756(167) 97Mo 96.906 0201(20) 0.095 551(96) 98Mo 97.905 4069(20) 0.241 329(241) 100Mo 99.907 476(6) 0.096 335(96) A From Audi and Wapstra (1993). B From Rosman and Taylor (1998) and Moore and others (1974). 70 analysis of molybdenum (Siebert and others, 200la, Earnshaw, 1997). Native palladium is found in placer 2001b; Anbar and others, 2001). Anbar and others deposits or in sulfides or arsenides of copper and (2001) observe a range in 97Mo/95Mo during ion- nickel sulfide ores. The largest single use of exchange chromatography in the laboratory of ~3 %o. palladium is in electronic components, but large They note a variation in 97Mo/95Mo of -0.6 %o amounts are also used in dehydrogenation catalysis between a natural sample of MoS2 and a laboratory and dentistry (Greenwood and Earnshaw, 1997). reference material, which is a variation in AT(Mo) of Shima and others (1978) analyzed samples from 0.002, substantially less than the uncertainty in the Sudbury, Ontario, Canada (containing 0.25 mg/kg Pd) standard atomic weight of molybdenum of 0.01. and from the western Bushveld Igneous Complex in Smaller isotopic variations were observed by Siebert South Africa at Lonrho (containing 7.7 mg/kg Pd) for and others (200la), who measured 98Mo/95Mo palladium isotopic composition (table 39) using differences of-0.3 %o and +0.1 %o for fine-grained positive ion thermal ionization mass spectrometry. sediments relative to their reference; they found a Although Shima and others found no variation in -0.3 %o Mo/95Mo difference between a hydrothermal isotopic composition in these terrestrial samples, molybdenite and their reference. In contrast to the Mermelengas and others (1981) reported evidence of preceding studies, no isotopic variability within a isotope fractionation in a precious metal concentrate precision of 0.01 %o to 0.1 %o could be seen in from the Atok mine in South Africa. A concentrate terrestrial materials by Dauphas and others (2001) from a second mine, also from the Bushveld who used multiple collector inductively coupled Complex, was not fractionated. Rosman and others plasma hexapole mass spectrometry. (1989) reanalyzed these samples together with another Siebert and others (200Ib) analyzed Atlantic, 4 mineral concentrates and 1 highly refined sample of Pacific, and Indian ocean water and found no <598Mo palladium metal. Their results are shown in table 40. variation within analytical uncertainty (±0.1 %o). Rosman and others (1989) confirmed that Their range in <598Mo for sediments is -2.7 %o to palladium samples with relatively high atomic -2.0 %o. Their range for crusts of ferromanganese weights are present in the Atok mine, which is deep-sea nodules is -3.1 %o to -2.7 %o. located in the eastern part of the Bushveld complex. No heavy-isotope enrichment was found in samples from the western part of the Bushveld Complex. Palladium A(Pd) = 106.42(1) Rosman and others concluded that isotope fractionation in the Atok-mine sample was produced Palladium is relatively scarce in the Earth's crust; by natural geochemical processes rather than by its concentration is about 0.15 mg/kg (Greenwood and industrial processing or purification. Table 39. Palladium isotopic composition of a sample from Sudbury, Ontario, Canada [Atomic mass given in unified atomic mass units, u] Isotope Atomic Mass Mole Fraction 102pd 101.905 607(3) 0.0102(1) 104pd 103.904 034(5) 0.1114(8) ' 05Pd 104.905 083(5) 0.2233(8) 106pd 105.903 484(5) 0.2733(3) 108pd 107.903 895(4) 0.2646(9) nopd 109.905 153(12) 0.1172(9) From Audi and Wapstra (1993). From Rosman and Taylor (1998) and Shima and others (1978). 71 Table 40. Isotope fractionation of naturally occurring palladium-bearing samples [Pd concentration given in weight percent; isotope fractionation given in %o/mass unit relative to reagent PdA] Isotope fractionation Location Pd concentration Mermelengas and Rosman and others, 1981 others, 1989 Atok mine 13.3 +3.8 ± 0.3B +3.6 ± 0.2B Merensky Reef 3^ -0.2 ± 0.3B +0.1 ± 0.2 Union Section 0.6 +0.1 ±0.2 Amandelbult Section 2.4 +0.2 ± 0.2 Rustenburg Section, code R 3 +0.2 ± 0.3 Rustenburg Section, code C 20 +0.1 ±0.1 y-i Code 84/85, unknown section 99.99 +0.1 ±0.2 A Same reagent used in both studies. B Average of 2 measurements, c Probably South Africa. Tellurium A(Te) = 126.60(3) this &122/&130 value, the initial Te° product would have A^To) = 127.58. By analogy with sulfur and Tellurium is also relatively scarce (seventy-third selenium, the natural variation in tellurium isotope in order of crustal abundance). The principal abundances because of mass fractionation probably commercial source of tellurium is the anode slime is higher than reported here. deposited during electrolytic refining of copper. The In contrast to mass fractionation effects, highly United States, Japan, and Canada dominate anomalous tellurium isotope abundances have been production. Tellurium is used in iron and steel found near the Oklo natural fission reactor found in production, in non-ferrous metal production, and in Gabon (Loss and others, 1988; Loss and others, catalysts. 1989). Thus, ^r(Te) at Oklo is highly variable and Tellurium has been analyzed for isotopic this variability is dependent upon many factors, such composition using both negative ion thermal as the amount of fissiogenic tellurium present, neutron ionization mass spectrometry (Smithers and Krouse, capture reactions involving tellurium nuclei, and the 1968) and positive ion thermal ionization mass migration (retention) of precursor nuclei. For spectrometry (Wachsmann and Heumann, 1992). example, the range reported for the ratio Although tellurium has 8 stable isotopes (table 41), (fission product 125'128>130Te)/(primordial Te) for Zone few determinations of tellurium isotope abundance 9 at Oklo was 81 to 190 (Loss and others, 1989). variation have been performed (Smithers and The maximum corresponds to a molar concentration Krouse, 1968; Smith and others, 1978). Absolute of 130Te of about 80 percent as compared to 34 isotope-abundance measurements have not been percent found for the "normal" abundance. Fission conducted on a specimen used in relative isotope product tellurium isotopes increase ^4r(Te), so that ratio investigations. The reported maximum range AT(To) is greater than 129. ratio) is 4 %o, the ranges being similar for natural telluride minerals, native Te, and commercial K2TeOs (Smithers and Krouse, 1968). A kinetic isotope effect kui/kiw, as high as 1.008, has been obtained during TeOs2" reduction. If tellurite (TeO32~) with A(Te) = 127.603 were reduced with 72 Table 41. Tellurium isotopic composition of a naturally occurring material [Atomic mass given in unified atomic mass units, u] Isotope Atomic MassA Mole Fraction8 120Te 119.904026(11) 0.000 96(1) 122Te 121.903 0558(29) 0.026 03(1) 123Te 122.9042711(20) 0.009 08(1) 124Te 123.902 8188(16) 0.048 16(2) i25Te 124.904 4241(20) 0.071 39(2) ,26^ 125.903 3049(20) 0.189 52(4) 128^ 127.904 4615(19) 0.316 87(4) 130Te 129.906 2229(21) 0.337 99(3) A From Audi and Wapstra (1993). >r.io n^,A T^,,,I^». /i nno\ n^A G-W-,;^!-. n»j ~4-i, /i men Thallium A(TI) = 204.3833(2) Halliday (1999) found isotopic variation among reagents, igneous rocks, and crusts of The average concentration of thallium in the ferromanganese deep-sea nodules (table 43 and Earth's crust is 0.7 mg/kg (Greenwood and Earnshaw, figure 15). Rehkamper and others (2001) confirmed 1997). Thallium is recovered from the smelting of isotopic variation in ferromanganese crusts. The observed isotopic variation of thallium extends zinc-lead ores and from flue dust emitted during outside the limits of the uncertainty of its atomic sulfide roasting for the manufacture of sulfuric acid. weight (figure 15). In future meetings, CAWIA may There are no major commercial uses of thallium. consider expanding the atomic-weight uncertainty of thallium or consider adding a footnote g to thallium Reference materials and reporting of isotope in the Table of Standard Atomic Weights (Coplen, ratios 2001) to indicate that "geological specimens are Thallium isotope ratios are reported relative to known in which the element has an isotopic the primary reference NIST SRM 997 elemental composition outside the limits for normal material." thallium metal, with an assigned <5205T1 value of 0 %o. It is not now assigned a footnote g. Thallium isotope ratio measurements have been Igneous rocks The 73 Table 42. Isotopic composition ofSRM997 elemental thallium [Atomic mass given in unified atomic mass units, u] Isotope Atomic Mass" Mole Fraction 203Tl 202.972 329(3) 0.295 24(9) 205Tl 204.974 412(3) 0.704 76(9) From Audi and Wapstra (1993). From Rosman and Taylor (1998) and Dunstan and others (1980). Table 43. Thallium isotopic composition of selected thallium-bearing materials [Values for Minimum <5205T1 Value Maximum <5205T1 Value Substance Atomic Weight 204.3830 204.3835 204.3840 1 , , , , | . i . . | Mole Fraction of 205TI 0.7046 0.7047 0.7048 0.7049 0.7050 0.7051 1 ' I ' . I ' I , , [ STANDARD ATOMIC WEIGHT ' IGNEOUS ROCKS 1 1 SEDIMENTARY ROCKS ! SRM 997 REAGENTS 1 , , , , 1 , , , , 1 , , , , 1 , , , , 1 , , , , 1 , , i , -1 .0 -0.5 0.0 0.5 1.0 1.5 6 205ZUOTI, in %0 relative to SRM 997 Figure 15. Thallium isotopic composition and atomic weight of selected thallium-bearing materials. The 6C-205r Tl scale and the 205T1 mole-fraction scale were matched using the data in table 42; therefore, uncertainty in placement of the atomic-weight scale and the 205T1 mole-fraction scale relative to the <5205T1 scale is equivalent to ±0.4 %o. 74 Ocean (Rehkamper and others, 2001). For the sample There are no internationally distributed isotopic of a material of natural terrestrial origin with the reference materials for the elements zinc, selenium, highest 205T1 content in the literature (<5205T1 = molybdenum, palladium, and tellurium. Preparation +1.43 %o), the mole fraction of 205rZUDT1 is 0.705 06 and of such materials will help to make isotope ratio = 204.383 91 (Rehkamper and others, 2001). measurements among laboratories comparable. Reagents The 6o205 Tl of thallium-bearing Many laboratories are not reporting isotope laboratory reagents ranges from -0.14 %o to +0.02 %o abundance variations relative to current (Rehkamper and Halliday, 1999). internationally distributed isotopic reference materials. For example, some laboratories are not reporting <556Fe values relative to IRMM-014 Summary and Conclusions elemental iron. Some laboratories are not reporting ^4Ca values relative to SRM 915a calcium The standard atomic weights and their carbonate. The International Union of Pure and uncertainties tabulated by the Commission on Atomic Applied Chemistry may consider preparation of Weights and Isotopic Abundances of the International guidelines discussing the advantages of reporting Union of Pure and Applied Chemistry are intended to delta values relative to present iron and calcium apply to most normal terrestrial materials and isotopic reference materials. laboratory reagents. The Subcommittee on Natural This report should not be considered as a Isotopic Fractionation was formed to investigate the comprehensive compilation of stable isotope ratios in effects of isotope abundance variations of elements the literature. Rather, this report is intended to upon their atomic weights and atomic-weight illustrate ranges of isotope-abundance variations that uncertainties. The aims of the subcommittee are (1) may be encountered in natural and anthropogenic to identify elements for which the uncertainties of the compounds, and in reagents and naturally occurring standard atomic weights are significantly larger than terrestrial materials. measurement uncertainties because of isotope The minimum and maximum concentrations of a abundance variations caused by fractionation selected isotope in materials of natural terrestrial processes (excluding variations caused by origin of selected chemical elements discussed in this radioactivity) and (2) to provide information about the report are given below: range of atomic-weight variations in specific chemical compounds of each of these elements. The following Isotope Minimum, mole Maximum, mole elements were found to meet these criteria: hydrogen, fraction fraction 2H 0.000 0255 0.000 1838 lithium, boron, carbon, nitrogen, oxygen, silicon, 7Li sulfur, chlorine, copper, and selenium. The chemical 0.9227 0.9278 UB 0.7961 0.8107 elements magnesium, calcium, iron, zinc, 13C molybdenum, palladium, and tellurium have isotopic 0.009 629 0.011 466 15N 0.003 462 0.004 210 variations in materials of natural terrestrial origin, but 18Q these variations do not require expansion of the 0.001 875 0.002 218 26Mg 0.1099 0.1103 uncertainty of the atomic weights of these elements. 30Si Two chemical elements, chromium and thallium, have 0.030 816 0.031 023 34S 0.0398 0.0473 isotope-abundance variations in materials of natural 37C1 terrestrial origin that may exceed atomic-weight 0.240 77 0.243 56 "Ca 0.020 82 0.020 92 uncertainties. 53Cr With the proliferation of microprobe techniques 0.095 01 0.095 53 56Fe 0.917 42 0.917 60 for isotope measurements, large variations in isotopic 65Cu composition have been found in source materials over 0.3066 0.3102 205rp| distances of the order of 1 to 1000 um (McKibben 0.704 72 0.705 06 and Eldridge, 1994). Such data are excluded from this compilation, as are data from extraterrestrial materials and elements exhibiting isotope-abundance variation caused by radioactivity. 75 References Cited Aravena, R., Frape, S.K., Moore, B.J., Van Warmerdam, E.M., and Drimmie, R.J., 1996, Use Abell, P.I., 1985, Oxygen isotope ratios in modern of environmental isotopes in organic contaminants African gastropod shells: A data base for research in groundwater systems, in Water Resources paleoclimatology: Chemical Geology, v. 58, p. 183- Management, Vol. 1: Vienna, Austria, International 193. Atomic Energy Agency, p. 31-42. Agyei, E.K., and McMullen, C.C., 1968, A study of the Audi, G., and Wapstra, A.H., 1993, The 1993 atomic isotopic abundance of boron from various sources: mass evaluation: Nuclear Physics, v. A565, p. 1-66. Canadian Journal Earth Science, v. 5, p. 921-927. Baertschi, P., 1976, Absolute 18O content of Standard Aldaz, L., and Deutsch, S., 1967, On a relationship Mean Ocean Water: Earth and Planetary Science between air temperature and oxygen isotope ratio of Letters, v. 31, p. 341-344. snow and fira in the South Pole region: Earth Planetary Science Letters, v. 3, p. 267-274. Bainbridge, A.E., Suess, H.E., and Friedman, I., 1961, Isotope composition of atmospheric hydrogen and Allard, P., 1983, The origin of hydrogen, carbon, methane: Nature, v. 192, p. 648-649. sulphur, nitrogen, and rare gases in volcanic exhalations: Evidence from isotope geochemistry, in Baker, A.J., and Fallick, A.E., 1989, Heavy carbon in Tazieff, H., and Sabroux, J.-C., eds., Forecasting two-billion-year-old marbles from Lofoten- Volcanic Events, Developments in Volcanology 1: Vesteralen, Norway: Implications for the New York, Elsevier, p. 337-386. Precambrian carbon cycle: Geochimica et Cosmochimica Acta, v. 53, p. 1111-1115. Altabet, M.A., and McCarthy, J.J., 1985, Temporal and spatial variations in the natural abundance of 15N in Ball, J.W., 1996, Thermodynamic and isotopic PON from a warm-core ring: Deep-Sea Research, v. systematics of chromium chemistry: Ph.D. 32, p. 755-772. Dissertation, Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona, Amberger, A., and Schmidt, H.L., 1987, Natiirliche 294 p. Isotopengehalte von Nitrat als Indikatoren fur dessen Herkunft: Geochimica et Cosmochimica Acta, v. 51, Bao, H., Thiemens, M.H., Farquhar, J., Campbell, p. 2699-2705. D.A., Lee, C.C.-H., Heine, K., and Loope, D.B., 2000, Anomalous 17O compositions in massive Ambrose, S.H., and DeNiro, M.J., 1989, Climate and sulphate deposits on the Earth: Nature, v. 406, p. habitat reconstruction using stable carbon and 176-178. nitrogen isotope ratios of collagen in prehistoric herbivore teeth from Kenya: Quaternary Research, Bassett, R.L., 1990, A critical evaluation of the available v. 31, p. 407-422. measurements for the stable isotopes of boron: Applied Geochemistry, v. 5, p. 541-554. Amundson, R., 1989, The use of stable isotopes in assessing the effect of agriculture on arid and Bassett, R.L., Buszka, P.M., Davidson, G.L., and semi-arid soils, in Rundel, P.W., and others, eds., Chong-Diaz, D., 1995, Identification of groundwater Stable Isotopes in Ecological Research: New York, solute sources using boron isotopic composition: Springer-Verlag, p. 318-341. Environmental Science and Technology, v. 29, p. 2915-2922. Anbar, A.D., 2001, Iron isotope biosignatures: promise and progress (abstract): EOS, Transactions of the Batard, F., Baubron, J.C., Bosch, B., Marce, A., and American Geophysical Union, v. 82, p. 173-179. Risler, J.J., 1982, Isotopic identification of gases of a deep origin in French thermomineral waters: Anbar, A.D., Knab, K.A., and Barling, J., 2001, Precise Journal of Hydrology, v. 56, p. 1-21. determination of mass-dependent variations in the isotopic composition of molybdenum using MC- Bau, M., von Blanckenburg, F., and Ohmoto, H., 2001, ICPMS: Analytical Chemistry, v. 73, p. 1425-1431. Iron isotope stratification of Late Archean seawater: evidence from dolomites and banded iron- Anbar, A.D., Roe, J.E., Barling, J., and Nealson, K.H., formations, in Eleventh Annual V.M. Goldschmidt 2000, Nonbiological fractionation of iron isotopes: Conference, Abstract 3709: LPI Contribution No. Science, v. 288, p. 126-128. 76 1088, Lunar and Planetary Institute, Houston (CD- the South Pacific: Geochimica et Cosmochimica ROM). Acta, v. 61, p. 569-576. Beard, B.L., and Johnson, C.M., 1999, High precision Bogdanov, Y.V., Golubchina, M.N., Prilutskiy, R.E., iron isotope measurements of terrestrial and lunar Toksubayev, A.I., and Feoktistov, V.P., 1972, materials: Geochimica et Cosmochimica Acta, v. 63, Some characteristics of sulfur isotopic composition p. 1653-1660. in iron sulfides of Paleozoic sedimentary rocks at Dzhezkazgan: Geochemistry International, v. 8, p. Beard, B.L., Johnson, C.M., Cox, L., Sun, H., Nealson, 856-858. K.H., and Aguilar, C., 1999, Iron isotope biosignatures: Science, v. 285, p. 1889-1892. Bohlke, J.K., and Coplen, T.B., 1995, Interlaboratory comparison of secondary reference materials for Beaudoin, G., Taylor, B.E., Rumble III, D., and nitrogen-isotope-ratio measurements, in Reference Thiemens, M., 1994, Variations in the sulfur isotope and intercomparison materials for stable isotopes of composition of troilite from the Canon Diablo iron light elements: Vienna, Austria, International meteorite: Geochimica et Cosmochimica Acta, v. Atomic Energy Agency, IAEA-TECDOC-825, p. 58, p. 4253^255. 51-66. Bebout, G.E., and Fogel, M.L., 1992, Nitrogen isotope Bohlke, J.K., Ericksen, G.E., and Revesz, K.M., 1997, tracers of metasedimentary rocks in the Catalina Stable isotope evidence for an atmospheric origin of Schist, California: Implications for metamorphic desert nitrate deposits in northern Chile and southern devolatilization history: Geochimica et California, U.S.A.: Chemical Geology, v. 136, p. Cosmochimica Acta, v. 56, p. 2839-2849. 135-152. Beneteau, K.M., Aravena, R., and Frape, S.K., 1999, Bohlke, J.K., Alt, J.C., and Muehlenbachs, K., 1984, Isotopic characterization of chlorinated solvents Oxygen isotope-water relations in altered deep-sea laboratory and field results: Organic Geochemistry, basalts: Low temperature mineralogic controls: v. 30, p. 739-753. Canadian Journal of Earth Science, v. 21, p. 67-77. Berger, A., and von Blanckenburg, F., 2001, High- Bohlke, J.K., Smith, R.L., Revesz, K.M., and temperature fractionation of Fe isotopes (abstract): Yoshinari, T., 2000, Quantifying reaction progress EOS, Transactions of the American Geophysical and isotope fractionation effects in denitrification: Union, v. 82, p. F1296. Integration of results for nitrate, nitrite, nitrous oxide, and nitrogen gas in shallow contaminated Bernard, C., 1978, Composition isotopique des mineraux ground water at Cape Cod, Massachusetts (abstract): secondaries des bauxites. Problemes de genese, PhD EOS, Transactions of the American Geophysical thesis, Univ. de Paris, Paris. Union, v. 81, p. SI86. Berry, J.A., 1988, Studies of mechanisms affecting the Brantley, S.L., Liermann, L., and Bullen, T.D., 2001, fractionation of carbon isotopes in photosynthesis, in Fractionation of Fe isotopes by soil microbes and Rundell, P.W., Ehleringer, J.R., and Nagy, K.A., organic acids: Geology, v. 29, 535-538. eds., Stable Isotopes in Ecological Research: New York, Springer-Verlag, p. 82-94. Brenna, J.T., 2001, Natural intramolecular isotope measurements in physiology: elements of the case Bird, M.I., Chivas, A.R., and Andrew, A.S., 1989, A for an effort toward high-precision position-specific stable-isotope study of lateritic bauxites: isotope analysis: Rapid Communications in Mass Geochimica et Cosmochimica Acta, v. 53, p. 1411- Spectrometry, v. 15, p. 1252-1262. 1420. Brenninkmeijer, C.A.M., 1993, Measurement of the Bird, M.I., Chivas, A.R., and Andrew, A.S., 1990, abundance of 14CO in the atmosphere and the Reply to comment by Chen, C.H., Liu, K.K., and 13C/12C and 18O/16O ratio of atmospheric CO with Shieh, Y.N., on "A stable isotope study of lateritic applications in New Zealand and Antarctica: Journal bauxites": Geochimica et Cosmochimica Acta, v. Geophysical Research, D, Atmospheres, v. 98, p. 54, p. 1485-1486. 10595-10614. Blattner, P., Grindley, G.W., and Adams, C.J., 1997, Bricout, J., 1978, Recherches sur le fractionnement des Low- ISO terrains tracking Mesozoic polar climates in isotopes stables de 1'hydrogene dans quelques 77 vegetaux: Revue de Cylologie et de Biologic Catanzaro, E.J., Murphy, T.J., Garner, E.L., and Vegetales Le Botaniste, v. 1, p. 133-209. Shields, W.R., 1966, Absolute isotopic abundance ratios and the atomic weight of magnesium: Journal Bricout, J., Merlivat, L., and Fontes, J.Ch., 1973, Sur of Research of the National Bureau of Standards la composition en isotopes stables de 1'eau des jus (U.S.), v. 70A, p. 453^58. d'orange: Academie des Sciences [Paris] Comptes Rendus, v. 274, p. 1803-1806. Cecile, M.P., Shakur, M.A., and Krouse, H.R., 1983, The isotopic composition of western Canadian Bryant, J.D., Luz, B., and Froelich, P.N., 1994, Oxygen barites and the possible derivation of oceanic isotopic composition of fossil horse tooth phosphate sulphate Cameron, A.E., 1955, Variation in the natural abundance Chan, L.-H., You, C-.F., and Leeman, W.P., 1995, of the lithium isotopes: Journal American Chemical Lithium isotope composition of Central American Society, v. 77, p. 2731-2733. volcanic arc lavas; evidence of slab-derived fluids in magma genesis: Geological Society of America, Carmody, R. W., and Seal II, R. R., 1999, Evaluation 1995 annual meeting, p. 38. of the sulfur isotopic composition and homogeneity of the Soufre de Lacq reference material: Chemical Chang, T.-L., and Li, W., 1990, A calibrated Geology, v. 153, p. 289-295. measurement of the atomic weight of carbon: Chinese Science Bulletin, v. 35, p. 290-296. Catanzaro, E.J., Champion, C.E., Garner, E.L., Marinenko, G., Sappenfield, K.M., and Shields, Chang, T.-L., Zhao, M.-T., Li, W., Wang, J., and W.R., 1970, NBS Special Publication 260-17, U.S. Qian, Q.-Y., 2001 a, Absolute isotopic composition Printing Office, 7 p. and atomic weight of zinc: International Journal Mass Spectrometry, v. 208, p. 113-118. Catanzaro, E.J., and Murphy, T.J., 1966, Magnesium isotope ratios in natural samples: Journal of Chang, V.T.-C., Galy, A., and O'Nions, R.K., 2001b, Geophysical Research, v. 71, p. 1271-1274. Mg isotopic composition of modern planktonic foraminifera, in Eleventh Annual V.M. Goldschmidt 78 Conference, Abstract 3426: LPI Contribution No. Coplen, T.B., Krouse, H.R., and Bo hike, J.K., 1992, 1088, Lunar and Planetary Institute, Houston (CD- Reporting of nitrogen-isotope abundances: Pure and ROM). Applied Chemistry, v. 64, p. 907-908. Chaussidon, M., and Marty, B., 1995, Primitive boron Coplen, T.B., Kendall, C., and Hopple, J., 1983, isotope composition of the mantle: Science, v. 269, Comparison of stable isotope reference samples: p. 383-386. Nature, v. 302, p. 236-238. Clark, I., and Fritz, P., 1997, Environmental Isotopes in Coplen, T.B., and Krouse, H.R., 1998, Sulphur isotope Hydrology: Boca Raton, Florida, Lewis Publishers, data consistency improved: Nature, v. 392, p. 32. 328 p. Cormie, A.B., Luz, B., and Schwarcz, H.P., 1994, Claypool, G.E., Threlkeld, C.N., Mankiewicz, P.N., Relationship between the hydrogen and oxygen Arthur, M.A., and Anderson, T.F., 1985, Isotopic isotopes of deer bone and their use in the estimation composition of interstitial fluids and origin of of relative humidity: Geochimica et Cosmochimica methane in slope sediment of the Middle America Acta, v. 58, p. 3439-3449. Trench, Deep Sea Drilling Project Leg 84: Initial Reports of the Deep Sea Drilling Project, v. 84, p. Coveney, R.M., Jr., Goebel, E.D., Zeller, E.J., 683-691. Dreschhoff, G.A.M., and Angino, E.E., 1987, Serpentinization and the Origin of Hydrogen Gas in Clayton, R.N., and Degens, E.T., 1959, Use of carbon Kansas: American Association of Petroleum isotope analyses of carbonates for differentiating Geologists Bulletin, v. 71, p. 39-48. fresh-water and marine sediments: American Association Petroleum Geologists Bulletin, v. 43, p. Craig, H., 1967, Ocean water, isotopic composition of: 890-897. McGraw-Hill Yearbook Science and Technology, New York, p. 268-271. Cline, J.D., and Kaplan, I.R., 1975, Isotopic fractionation of dissolved nitrate during Dansgaard, W., 1964, Stable isotopes in precipitation: denitrification in the eastern tropical north pacific Tellus, v. 16, p. 436-468. ocean: Marine Chemistry, v. 3, p. 271-299. Daughtry, A.C., Perry, D., and Williams, M., 1962, Coplen, T.B., 1988, Normalization of oxygen and Magnesium isotopic distribution in dolomite: hydrogen isotope data, Chemical Geology (Isotope Geochimica et Cosmochimica Acta, v. 26, p. 857- Geoscience Section), v. 72, p. 293-297. 866. _ 1993, Uses of environmental isotopes, in Alley, Dauphas, N., Reisberg, L., and Marty, B., 2001, W.M., ed., Regional ground-water quality: New Solvent extraction, ion chromatography, and mass York, Van Nostrand Reinhold, p. 227-254. spectrometry of molybdenum isotopes: Analytical Chemistry, v. 73, p. 2613-2616. _ 1994, Reporting of stable hydrogen, carbon, and oxygen isotopic abundances: Pure and Applied De Bievre, P., Gallet, M., Holden, N.E., and Barnes, Chemistry, v. 66, p. 273-276. I.L., 1984, Isotopic abundances and atomic weights of the elements: Journal of Physical and Chemical _ 1996, Atomic weights of the elements 1995: Pure Reference Data, v. 13, p. 809-891. and Applied Chemistry, v. 68, p. 2339-2359. De Bievre, P., Valkiers, S., and Peiser, H.S., 1994, New values for silicon reference materials, certified for ___ 2001, Atomic weights of the elements 1999: Pure isotope abundance ratios: Journal of Research of the and Applied Chemistry, v. 73, 667-683. National Institute of Standards and Technology, v. 99, p. 201-202. Coplen, T.B., Herczeg, A.L., and Barnes, C., 1999, Isotope engineering Using stable isotopes of the De Bievre, P., Valkiers, S., Peiser, H.S., Taylor, P.D.P., water molecule to solve practical problems, in Cook, and Hansen, P., 1996, The absolute isotopic P.G., and Herczeg, A.L., eds., Environmental tracers composition and atomic weight of nitrogen by in subsurface hydrology: Boston, Kluwer Academic isotope-ratio mass spectrometry: Metrologia, v. 33, Publishers, p. 79-110. p. 447-455. 79 De La Rocha, C.L., Brzezinski, M.A., and DeNiro, Reichard, E.G., Hauchman, F.S., and Sancha, A.M., M.J., 1997, Fractionation of silicon isotopes by eds., Interdisciplinary Perspectives on Drinking marine diatoms during biogenic silica formation: Water Risk Assessment and Management: Geochimica et Cosmochimica Acta, v. 61, p. 5051- International Association of Hydrological Sciences 5056. Publication 260, p. 63-73. ___ 2000, A first look at the distribution of the stable Desaulniers, D.E., Kaufmann, R.S., Cherry, J.A., and isotopes of silicon in natural water: Geochimica et Bentley, H.W., 1986, 37C1-35C1 variations in a Cosmochimica Acta, v. 64, p. 2467-2477. diffusion-controlled groundwater system: Geochimica et Cosmochimica Acta, v. 50, p. 1757- De La Rocha, C.L., Brzezinski, M.A., DeNiro, M.J., 1764. and Shemesh, A., 1998, Silicon-isotope composition of diatoms as an indicator of past oceanic change: Denser, W.G., 1970, Extreme 13C/12C variations in Nature, v. 395, p. 680-683. Quaternary dolomites from the continental shelf: Earth Planetary Science Letters, v. 8, p. 118-124. De La Rocha, C.L., and DePaolo, D.J., 2000, Isotopic evidence for variations in the marine calcium cycle Ding, T., Jiang, S., Wan, D., Li, Y., Li, J., Song, H., over the Cenozoic: Science, v. 289, p. 1176-1178. Liu, Z., and Yao, X., 1996, Silicon Isotope Geochemistry: Beijing, Geological Publishing de Laeter, Bohlke, J.R., De Bievre, P., Hidaka, H., House, 125 p. Peiser, H.S., Rosman, K.J.R., and Taylor, P.D.P., in press, The Atomic Weights of the Elements, Ding, T., Valkiers, S., Kipphardt, H., De Bievre, P., Review 2000: Pure Applied Chemistry. Taylor, P.D.P., Gonfiantini, R., and Krouse, H.R, 2001, Calibrated sulfur isotope abundance ratios of De Wit, J.C., Van der Straaten, C.M., and Mook, three IAEA sulfur isotope reference materials and V- W.G., 1980, Determination of the absolute D/H ratio CDT with a reassessment of the atomic weight of of V-SMOW and SLAP: Geostandards Newsletter, sulfur: Geochimica et Cosmochimica Acta, v. 65, p. v. 4, p. 33-36. 2433-2437. Deines, P., 1968, The carbon and oxygen isotopic Ding, T.P., Wan, D.F., Li, J.C., Jiang, S.Y., Song, composition of carbonates from a mica peridotite H.B., Li, Y.H., and Li, Z.J., 1988, Analytic method dike near Dixonville, Pennsylvania: Geochimica et of silicon isotopes and its geological applications (in Cosmochimica Acta, v. 32, p. 613-625. Chinese): Kuangchang Dizhi (Mineral Deposits), v. 7, p. 90-95. ___ 1980, The isotopic composition of reduced organic carbon, in Fritz, P., and Fontes, J.Ch., eds., Ding, T., Wang, C, Zhang, F. and Wan, D., 1998, Handbook of Environmental Isotope Geochemistry, Silicon isotope fractionation of some surface Volume 1, The Terrestrial Environment, A: processes (A study on river water and plants): Amsterdam, The Netherlands, Elsevier Scientific International Conference on Geochronology, Publishing Co., p. 329^02. Cosmochronology and Isotope Geology, Ninth, Beijing, 1998 [Abstracts], Chinese Science Bulletin, Deines, P., and Gold, D.P., 1973, The isotopic v. 43 Supplement, p. 33. composition of carbonatite and kimberlite carbonates and their bearing on the isotopic composition of Dixon, P.R., Janecky, D.R., Perrin, R.E., Rokop, D.J., deep-seated carbon: Geochimica et Cosmochimica Unkefer, P.L., and Spall, W.D., 1992, in Acta, v. 37, p. 1709-1733. Unconventional stable isotopes: Iron, in Kharaka, Y.K., and Maest, A.S., eds, Water-Rock Interaction, Deines, P., Viljoen, F., and Harris, J.W., 2001, Volume 2, Moderate and High Temperature Implications of the carbon isotope and mineral Environments: A.A. Balkema, Rotterdam, The inclusion record for the formation of diamonds in Netherlands, p. 915-918. the mantle underlying a mobile belt: Venetia, South Africa: Geochimica et Cosmochimica Acta, v. 65, p. Dole, M., 1935, The relative atomic weight of oxygen in 813-838. water and in air: Journal of the American Chemical Society, v. 57, p. 2731. Densmore, J.N., and Bohlke, J.K., 2000, Use of nitrogen isotopes to determine sources of nitrate Dole, M., Lange, G.A., Rudd, D.P., and Zaukelies, contamination in two desert basins in California, in D.A., 1954, Isotopic composition of atmospheric 80 oxygen and nitrogen: Geochimica et Cosmochimica Eggenkamp, H.G.M., and Coleman, M.L., 1993, Acta, v. 6, p. 65-78. Extreme Edmond, J.M, Measures, C., McDuff, R.E., Chan, Faure, G., Hoefs, J., Jones, L.M., Curtis, J.B., and L.H., Collier, R., Grant, B, Gordon, L.I., and Pride, D.E., 1988, Extreme 18O depletion in calcite Corliss, J.B., 1979, Ridge crest hydrothermal and chert clasts from the Elephant Moraine on the activity and the balance of the major and minor East Antarctic ice sheet: Nature, v. 332, p. 352-354. elements in the oceans: The Galapagos data: Earth and Planetary Science Letters, v. 46, p. 1-18. Finley, H.O., Eberle, A.R., and Rodden, C.J., 1962, Isotopic boron composition of certain boron Eggenkamp, H.G.M., 1994, 81 Fontes, J.Ch., and Gonfiantini, R., 1967, Comportement Fritz, P., and Fontes, J.Ch., 1989, Handbook of isotopique au cours de 1'evaporation de deux bassins Environmental Isotope Geochemistry, Volume 3, The Sahariens: Earth Planetary Science Letters, v. 3, p. Marine Environment, A: Amsterdam, The 258-266. Netherlands, Elsevier Science Publishers, 424 p. Francey, R.J., and Tans, P.P., 1987, Latitudinal Fry, B., and Sherr, E.B., 1984, (513C measurements as variation in oxygen-18 of atmospheric CO2: Nature, indicators of carbon flow in marine and freshwater v. 327, p. 495^97. ecosystems: Contributions Marine Science, v. 27, p. 13-47. Frape, S.K., Bryant, G., Blomqvist, R., and Ruskeeniemi, T., 1995, Evidence from stable Fuge, R., 1974, Chlorine, in Wedepohl, K.H., and others, chlorine isotopes for multiple sources of chloride in eds., Handbook of Geochemistry Vol. II-2: Berlin, groundwaters from crystalline shield environments, Springer-Verlag, Section 17-B Isotopes in Nature, in Isotopes in Water Resources Management, Vol. 1: p. 17-B-1-17-B-3. Vienna, Austria, International Atomic Energy Agency, p. 19-30. Gabler, H.-E., and Bahr, A., 1999, Boron isotope ratio measurements with a double-focusing magnetic Freyer, H.D., 1978a, Seasonal trends of NH4+ and NO3 sector ICP mass spectrometer for tracing nitrogen isotope composition in rain collected at anthropogenic input into surface and ground water: Julich, Germany: Tellus, v. 30, p. 83-92. Chemical Geology, v. 156, p. 323-330. ___ 1978b, Preliminary studies on atmospheric Gale, N.H., Woodhead, A.P., Stos-Gale, Z.A., Walder, nitrogenous trace gases: Pure and Applied A., and Bowen, I., 1999, Natural variations detected Geophysics, v. 116, p. 393-404. in the isotopic composition of copper: Possible applications to archaeology and geochemistry: Freyer, H.D., and Aly, A.I.M., 1974, Nitrogen-15 International Journal of Mass Spectrometry, v. 184, variations in fertilizer nitrogen: Journal of p. 1-9. Environmental Quality, v. 3, p. 405-406. Galimov, E.M., 1985, The relation between formation Freyer, H.D., Kobel, K., Delmas, R.J., Kley, D., and conditions and variations in isotopic composition of Legrand, M.R., 1996, First results of 15N/14N ratios diamonds: Geochemistry International, v. 22, no. 1, in nitrate from alpine and polar ice cores: Tellus, v. p. 118-142. 48B, p. 93-105. Galy, A., Bar-Matthews, M., Halicz, L., and O'Nions, Friedman, I., and O'Neil, J.R., 1977, Compilation of R.K., 2000, Mg isotope fractionation during Stable Isotope Fractionation Factors of Geochemical speleothem formation, Goldschmidt 2000 Interest, U.S. Geological Survey Professional Paper Conference, 3rd, September, 2000: Cambridge, 440-KK, Data of Geochemistry, Sixth Edition, Cambridge Publications, Journal of Conference Chapter KK, p. KK1-KK12. Abstracts, v. 5(2), p. 422. __ 1978, Hydrogen, in Wedepohl, K.H., ed., Galanter, M., Sigman, D.M., Levy, H., Bohlke, J.K., Handbook of Geochemistry II-1: Berlin, Springer- Lipshultz, F., and Steig, E., 2000, Controls on the Verlag, Section 1-B Isotopes in Nature, p. 1B1-1B8. oxygen isotopic composition of atmospherically- derived nitrate (abstract): EOS, Transactions of the Friedman, I., and Scholz, T.G., 1974, Isotopic American Geophysical Union, v. 81, p. F191. composition of atmospheric hydrogen, 1967-1969: Journal of Geophysical Research, v. 79, p. 785-788. Gao, Y.Q, and Marcus, R.A., 2001, Strange and unconventional isotope effects in ozone formation: Fritz, P., Clark, I., Fontes, J-Ch., Whiticar, M.J., and Science, v. 293, p. 259-263. Faber, E., 1992, Deuterium and 13C evidence for low temperature production of hydrogen and Garlick, G.D., 1969, Oxygen, in Wedepohl, K.H., ed., methane in a highly alkaline groundwater Handbook of Geochemistry: Berlin, Springer- environment in Oman, in Kharaka, Y.K., and Maest, Verlag, Section B, The Stable Isotopes of Oxygen, A., eds., Water-Rock Interaction: Rotterdam, The p. 8B1-8B27. Netherlands, A.A. Balkema, Vol. 1, Low Temperature Environments, p. 793-796. Gehlen, K., and Nielsen, H., 1969, Schwefel-Isotope aus Blei-zink-Erzen von Oberschlesien: Mineralium 82 Deposita (International Journal for Geology, Haendel, D., Muhle, K., Nitzsche, H.-M., Stiehl, G., Mineralogy, and Geochemistry of Mineral Deposits), and Wand, U., 1986, Isotopic variations of the fixed v. 4, p. 308-310. nitrogen in metamorphic rocks: Geochimica et Cosmochimica Acta, v. 50, p. 749-758. Gerling, P., Whiticar, M.J., and Faber, E., 1988, Extreme isotope fractionation of hydrocarbon gases Hagemann, R., Nief, G., and Roth, E., 1970, Absolute in Permian salts: Advances in Organic isotopic scale for deuterium analysis of natural Geochemistry, v. 13, p. 335-341. waters. Absolute D/H ratio for SMOW: Tellus, v. 22, p. 712-715. Ghent, E.D., and O'Neil, J.R., 1985, Late Precambrian marbles of unusual carbon-isotope composition, Halicz, L., Galy, A., Belshaw, N.S., and O'Nions, R.K., southeastern British Columbia: Canadian Journal 1999, High-precision measurement of calcium Earth Science, v. 22, p. 324-329. isotopes in carbonates and related materials by multiple collector inductively coupled plasma mass Goldberg, E.D., Somayajulu, B.L.K., Galloway, J., spectrometry (MC-ICP-MS): Journal of Analytical Kaplan, I.R., and Faure, G., 1969, Differences Atomic Spectrometry, v. 14, p. 1835-1838. between barites of marine and continental origins: Geochimica et Cosmochimica Acta, v. 33, p. 287- Harris, J.W., 1987, Recent physical, chemical, and 289. isotopic research of diamond in Nixon, P.H., ed., Mantle Xenoliths: New York, John Wiley and Sons Gonfiantini, R., 1978, Standards for stable isotope Ltd., p. 477-499. measurements in natural compounds: Nature, v. 271, p. 534-536. Hathaway, J.C., and Degens, E.T., 1969, Methane-derived marine carbonates of Pleistocene Gonfiantini, R., Stichler, W., and Rozanski, K., 1995, age: Science, v. 165, p. 690-692. Standards and intercomparison materials distributed by the International Atomic Energy Agency for Heaton, T.H.E., 1986, Isotopic studies of nitrogen stable isotope measurements, in Reference and pollution in the hydrosphere and atmosphere~A intercomparison materials for stable isotopes of light Review: Chemical Geology, v. 59, p. 87-102. elements: Vienna, Austria, International Atomic Energy Agency, IAEA-TECDOC-825, p. 13-29. ___ 1987, 15N/14N ratios of nitrate and ammonium in rain at Pretoria, South Africa: Atmospheric Gonsior, B., Friedman, I., and Lindenmayr, G., 1966, Environment, v. 21, p. 843-852. New tritium and deuterium measurements in atmospheric hydrogen: Tellus, v. 18, p. 256-261. Hemming, N.G., and Hanson, G.N., 1992, Boron isotopic composition and concentration in modern Goodfriend, G.A., and Magaritz, M., 1987, Carbon and marine carbonates: Geochimica et Cosmochimica oxygen isotope composition of shell carbonate of Acta, v. 56, p 537-543. desert land snails: Earth and Planetary Science Letters, v. 86, p. 377-388. Hendry, M.J., Krouse, H.R., and Shakur, M.A., 1989, Interpretation of oxygen and sulfur isotopes from Graham, C.M., and Sheppard, S.M.F., 1980, dissolved sulfates in tills of Southern Alberta, Experimental hydrogen isotope studies, II. Canada: Water Resources Research, v. 25, p. 567- Fractionations in the systems epidote-NaCl-H2O, 572. epidote-CaC^-HiO and epidote-seawater, and the hydrogen isotope composition of natural epidotes: Herbel, M.J., Johnson, T.M., Oremland, R.S., and Earth and Planetary Science Letters, v. 49, p. 237- Bullen, T.D., 2000, Fractionation of selenium 251. isotopes during bacterial respiratory reduction of selenium oxyanions: Geochimica et Cosmochimica Gray, J., and Thompson, P., 1977, Climatic information Acta, v. 64, p. 3701-3709. form 18O/16O analysis of cellulose, lignin and whole wood from tree rings: Nature, v. 270, p. 708-709. Hillaire-Marcel, G., 1986, Isotopes and food, in Fritz, P., and Fontes, J.Ch., eds., Handbook of Environmental Greenwood, N.N., and Earnshaw, A., 1997, Chemistry Isotope Geochemistry, Volume 2, The Terrestrial of the Elements, Second Edition: Butterworth Environment, B: Amsterdam, The Netherlands, Heinemann, Oxford, 1340 p. Elsevier Scientific Publishing Co., p. 507-547. 83 Hoefs, J., 1987, Stable Isotope Geochemistry (3rd Ed.): IAEA, 1981, Gat, J.R., and Gonfiantini, R., eds., Stable New York, Springer-Verlag, 241 p. Isotope Hydrology, Deuterium and Oxygen-18 in the Water Cycle: Vienna, Austria, International Atomic Hoefs, J., and Sywall, M., 1997, Lithium isotope Energy Agency, Technical Reports Series No. 210, composition of Quaternary and Tertiary biogene 337 p. carbonates and a global lithium isotope balance: Geochimica et Cosmochimica Acta, v. 61, p. 2679- IRMM, 2001, Certificate spike isotopic reference material 2690. IRMM-610: Geel, Belgium, Institute for Reference Materials and Measurements, 3 p. Hoering, T.C., 1955, Variations of nitrogen-15 abundance in naturally occurring substances: Ishikawa, T., and Nakamura, E., 1993, Boron isotope Science, v. 122, p. 1233-1234. systematics of marine sediments: Earth Planetary Science Letters, v. 117, p. 567-580. Hoering, T.C., and Moore, H.E., 1958, The isotopic composition of the nitrogen in natural gases and International Organization for Standardization, 1992, associated crude oils: Geochimica et Cosmochimica ISO-31-0, Quantities and Units, Part 0, General Acta, v. 13, p. 225-232. Principles, subclause 2.3.3: Geneva, International Organization for Standardization, 7 p. Hoering, T.C., and Parker, P.L., 1961, The geochemistry of the stable isotopes of chlorine: IUPAC (Commission on Atomic Weights and Isotopic Geochimica et Cosmochimica Acta, v. 23, p. 186- Abundances), 1994, Atomic Weights of the 199. Elements 1993: Pure and Applied Chemistry, v. 66, p. 2423-2444. Hofmann, B.A., and Bernasconi, S.M., 1998, Review of occurrences and carbon isotope geochemistry of Janik, C.J., Nehring, N.L., and Truesdell, A.H., 1983, oxalate minerals: implications for the origin and fate Stable isotope geochemistry of thermal fluids from of oxalate in diagenetic and hydrothermal fluids: Lassen Volcanic National Park, California (abstract): Chemical Geology, v. 149, p. 127-146. EOS, Transactions American Geophysical Union, v. 7, p. 295. Holden, N.E., Martin, R.L., and Barnes, I.L., 1984, Isotopic compositions of the elements 1983: Pure Jeffrey, A.W.A., Kaplan, I.R., Poreda, R.J., Craig, H., Applied Chemistry, v. 56, p. 675-694. and Armannsson, H., 1986, Stable isotope geochemistry of geothermal and sedimentary gases: Horrigan, S.G., Montoya, J.P., Nevins, J.L., and Extended Abstracts of International Symposium on McCarthy, J.J., 1990, Natural isotopic composition Water Rock Interaction, v. 5, p. 290-293. of dissolved inorganic nitrogen in the Chesapeake Bay: Estuarine, Coastal and Shelf Science, v. 30, p. Jeffries, M.O., and Krouse, H.R., 1984, Isotope 393-410. geochemistry of stratified water bodies on northern Ellesmere Island, Canadian Arctic: Mitteilungen, v. Huang, M.J., Li, R.Q., Liu, D.Y., Shen, Z.J., Tang, 159-169. S.H., and Chen, W.S., 1991, A study on exploration mineralogy and mineral prediction of rock-bounded Jendrzejewski, N., Eggenkamp, H.G.M., and Coleman, metallogenic series of ore deposits in southern M.L., 2001, Characterisation of chlorinated Hunan (in Chinese): Hunan Bureau of Geology and hydrocarbons from chlorine and carbon isotopic Mineral Resources, 97 p. compositions: scope of application to environmental problems: Applied Geochemistry, v. 16, p. 1021- Hiibner, H., 1986, Isotope effects of nitrogen in the soil 1031. and biosphere, in Fritz, P., and Fontes, J.Ch., eds., Handbook of Environmental Isotope Geochemistry, Jiang, S.Y., Ding, T., and Wan, D.F., 1992, A study on Volume 2, The Terrestrial Environment, B: silicon and oxygen isotope geochemistry of some Amsterdam, The Netherlands, Elsevier Scientific lead-zinc ore deposits in China (in Chinese): Publishing Co., p. 361-425. Chinese Science Bulletin, v. 37, p. 1022-1027. Hut, G., 1987, Consultants' group meeting on stable Johnson, T.M., Bullen, T.D., and Zawislanski, P.T., isotope reference samples for geochemical and 2000, Selenium stable isotope ratios as indicators of hydrological investigations: Vienna, International sources and cycling of selenium: results from the Atomic Energy Agency, 42 p. northern reach of San Francisco Bay: 84 Environmental Science and Technology, v. 34, p. Kaufmann, R.S., Long, A., Bentley, H.W., and Davis, 2075-2079. S.N., 1984, Natural chlorine isotope variations: Nature, v. 309, p. 338-340. Johnson, T.M., Herbel, M.J., Bullen, T.D., and Zawislanski, P.T., 1999, Selenium isotope ratios as Kaufmann, R.S., Long, A., and Campbell, D.J., 1988, indicators of selenium sources and oxyanion Chorine isotope distribution in formation waters, reduction: Geochimica Cosmochimica Acta, v. 63, Texas and Louisiana: American Association of p. 2775-2783. Petroleum Geologists Bulletin, v. 72, p. 839-844. Johnson, C.A., Mast, M.A., and Kester, C.L., 2001, Keeling, C.D., 1958, The concentration and isotopic Use of 17O/16O to trace atmospherically-deposited abundances of atmospheric carbon dioxide in rural sulfate in surface waters: a case study in alpine areas: Geochimica et Cosmochimica Acta, v. 13, p. watersheds in the Rocky Mountains: Geophysical 322-344. Research Letters, v. 28, p. 4483-4486. Keeling, C.D., Carter, A.F., and Mook, W.G., 1984, Jouzel, J., Lorius, C., Petit, J.R., Genthon, C., Barkov, Seasonal, latitudinal, and secular variations in the N.I., Kotlyakov, V.M., and Petrov, V.M., 1987, abundance and isotopic ratios of atmospheric CCh: 2. Vostok ice core: A continuous isotope temperature Results from oceanographic cruises in the Tropical record over the last climatic cycle (160,000 years): Pacific Ocean: Journal of Geophysical Research, v. Nature, v. 329, p. 403^08. 89D, p. 4615-4628. Junk, G., and Svec, H.J., 1958, The absolute abundance Keeling, C.D., Mook, W.G, and Tans, P.P., 1979, of the nitrogen isotopes in the atmosphere and Recent trends in the 13C/12C ratio of atmospheric compressed gas from various sources: Geochimica carbon dioxide: Nature, v. 277, p. 121-123. et Cosmochimica Acta, v. 14, p. 234-243. Keeling, C.D., Piper, S.C., and Heimann, M., 1989, A Kakihana, H., Kotaka, M., Satoh, S., Nomura, M., and three-dimensional model of atmospheric COz Okamoto, M., 1977, Fundamental studies on the transport based on observed winds: 4. Mean annual ion-exchange separation of boron isotopes: Bulletin gradients and interannual variations: Geophysical Chemical Society Japan, v. 50, p. 158-163. Monograph, v. 55, p. 305-363. Kanzaki, T., Yoshida, M., Nomura, M., Kakihana, H., Keith, M.L., Anderson, G.M., and Eichler, R., 1964, and Ozawa, T., 1979, Boron isotopic composition Carbon and oxygen isotopic composition of mollusk of fumarolic condensates and sassolites from shells from marine and fresh-water environments: Satsuma Iwo-Jima, Japan: Geochimica et Geochimica et Cosmochimica Acta, v. 28, p. 1757- Cosmochimica Acta, v. 43, 1859-1863. 1786. Kaplan, I.R., and Nissenbaum, A., 1966, Anomalous Keith, M.L, and Weber, J.N., 1964, Carbon and oxygen carbon-isotope ratios in nonvolatile organic material: isotopic composition of selected limestones and Science, v. 153, p. 744-745. fossils: Geochimica et Cosmochimica Acta, v. 28, p. 1787-1816. Karlsson, H.R., and Clayton, R.N., 1990, Oxygen and hydrogen isotope geochemistry of zeolites: Kendall, C., 1998, Tracing nitrogen sources and cycles in Geochimica et Cosmochimica Acta, v. 54, p. 1369- catchments, in Kendall, C., and McDonnell, J.J., 1386. eds., Isotope tracers in catchment hydrology: Amsterdam, Elsevier, p. 519-576. Kaufmann, R.S., and Arn6rsson, S., 1986, 37C1/35C1 Ratios in Icelandic Geothermal Waters: Fifth Kendall, C., and Grim, E., 1990, Combustion tube International Symposium on Water-Rock Interaction, method for measurement of nitrogen isotope ratios Extended Abstracts, v. 5, p. 325-327. using calcium oxide for total removal of carbon dioxide and water: Analytical Chemistry, v. 62, p. Kaufmann, R.S., Frape, S.K., McNutt, R.H., and 526-529. Eastoe, C., 1993, Chlorine isotope distribution of Michigan Basin formation waters: Applied Khar'kiv, A.D., Serenko, V.P., Zinchuk, N.N., Geochemistry, v. 8, p. 403-408. Mamchur, G.P., Mel'nik, Y.M., and Yarynikh, O.A., 1986, Carbon isotope composition of 85 carbonates from deep horizons in the Mir Pipe: Krouse, H.R., Brown, H.M., and Farquharson, R.B., Geochemistry International, v. 23, p. 79-85. 1977, Sulphur isotope compositions of sulphides and sulphates, DSDP Leg 37: Canadian Journal Earth Kirn, K.-R., and Craig, H., 1993, Nitrogen-15 and Science, v. 14, p. 787-793. oxygen-18 characteristics of nitrous oxide: A global perspective: Science, v. 262, p. 1855-1857. Krouse, H.R., and Coplen, T.B., 1997, Reporting of relative sulfur isotope-ratio data: Pure and Applied Klimchuk, A.B., Yablokova, N.L., and Olshtynsky, Chemistry, v. 69, p. 293-295. S.P., 1981, The regularities in the formation of gas composition of the air in the large karst caves of Krouse, H.R., and Grinenko, V.A., 1991, eds., Stable Podolia and Bukovina: Proceedings of Eighth Isotopes: Natural and Anthropogenic Sulphur in the International Congress of Speleology, v. 1, p. 21-23. Environment: New York, John Wiley and Sons, 440 P- Klotzli, U.S., 1992, Negative thermal ionisation mass spectrometry: A new approach to boron isotope Krouse, H.R., Levinson, A.A., Piggott, D., and Ueda, geochemistry: Chemical Geology (Isotope A., 1987a, Further stable isotope investigations of Geoscience Section) v. 101, p. 111-122. human urinary stones: Comparison with other body components: Applied Geochemistry, v. 2, p. 205- Knauth, L.P., and Lowe, D.R., 1978, Oxygen isotope 211. geochemistry of cherts from the Onverwacht Group (3.4 billion years), Transvaal, South Africa, with Krouse, H.R., Ritchie, R.G.S., and Roche, R.S., 1987b, implications for secular variations in the isotopic Sulfur isotopic composition of F^S evolved during composition of cherts: Earth Planetary Science the non-isothermal pyrolysis of sulfur-containing Letters, v. 41, p. 209-222. materials: Journal of Analytical and Applied Pyrolysis, v. 12, p. 19-29. Kolodny, Y., Luz, B., and Navon, O., 1983, Oxygen isotope variations in phosphate of biogenic apatites, Krouse, H.R., and Thode, H.G., 1962, Thermodynamic I. Fish bone apatite rechecking the rules of the properties and geochemistry of isotopic compounds: game: Earth Planetary Science Letters, v. 64, p. Canadian Journal Chemistry, v. 40, p. 367-375. 398^04. Kyser, T.K., 1986, Stable isotope variations in the Kornexl, B.E., Gehre, M., Hofling, R., and Werner, mantle, in Stable isotopes in high temperature R.A., 1999, On-line (518O measurement of organic geological processes, Mineralogical Society of and inorganic substances: Rapid Communications in America, Reviews of Mineralogy, Vol. 16, Valley, Mass Spectrometry, v. 13, p. 1685-1693. J.W., Taylor, H.P., Jr., and O'Neil, J.R. (eds.): Washington, D.C., Mineralogical Society of Kreitler, C.W., 1975, Determining the source of nitrate America, p. 141-164. in ground water by nitrogen isotope studies: Austin, Texas, University of Texas Austin, Bureau of ___ 1987, ed., Stable isotope geochemistry of low Economic Geology Report of Investigations No. 83, temperature processes: Toronto, Mineralogical 57 p. Association of Canada, Short Course Handbook, v. 13, 570 p. Kroopnick, P.M., 1985, The Distribution of 13C of SCO2 in the World Oceans: Deep-Sea Research, v. 32, p. Labeyrie, L.D., Pichon, J.J., Labracherie, M., Ippolito, 57-84. P., Duprat, J., and Duplessy, J.C., 1986, Melting history of Antarctica during the past 60,000 years: Kroopnick, P., and Craig, H., 1972, Atmospheric Nature, v. 322, p. 701-706. oxygen: Isotopic composition and solubility fractionation: Science, v. 175, p. 54-55. Lamberty, A., and De Bievre, P., 1991, Isotope dilution mass spectrometry of 10B and 6LiF reference deposits Krouse, H.R., 1980, Sulphur in our environment, in Fritz, used for the determination of the neutron lifetime: P., and Fontes, J.Ch., eds., Handbook of International Journal Mass Spectrometry and Ion Environmental Isotope Geochemistry, Volume 1, The Processes, v. 108, p. 189-198. Terrestrial Environment, A: Amsterdam, The Netherlands, Elsevier Scientific Publishing Co., p. Land, L.S., 1980, The isotopic and trace element 435-471. geochemistry of dolomite: the state of the art, in Zenger, D.A., ed., Concepts and Models of Dolomite 86 Formation: Society Economic Paleontology Longinelli, A., 1984, Oxygen isotopes in mammal bone Mineralogy, Special Publication, v. 28, p. 87-110. phosphate: A new tool for paleohydrological and paleoclimatological research?: Geochimica et Lane, G.A., and Dole, M., 1956, Fractionation of oxygen Cosmochimica Acta, v. 48, p. 385-390. isotopes during respiration: Science, v. 123, p. 574- 576. ___ 1989, Oxygen-18 and sulphur-34 in dissolved oceanic sulphate and phosphate, in Fritz, P., and Lawrence, J.R., and Taylor, H.P., Jr., 1972, Hydrogen Fontes, J.Ch., eds., Handbook of Environmental and oxygen isotope systematics in weathering Isotope Geochemistry, Volume 3, The Marine profiles: Geochimica et Cosmochimica Acta, v. 36, Environment, A: Amsterdam, The Netherlands, p. 1377-1393. Elsevier Scientific Publishing Co., p. 219-255. Lemarchand, D., Gaillardet, J., Lewin, £., and Allegre, Longinelli, A., and Craig, H., 1967, Oxygen-18 C.J., 2000, The influence of rivers on marine boron variations in sulfate ions in sea water and saline isotopes and implications for reconstructing past lakes: Science, v. 156, p. 56-59. ocean pH: Nature, v. 408, p. 951-954. Longinelli, A., and Nuti, S., 1968, Oxygen isotopic Letolle, R., 1980, Nitrogen-15 in the natural environment, composition of phosphorites from marine formations: in Fritz, P., and Fontes, J.Ch., eds., Handbook of Earth and Planetary Science Letters, v. 5, p. 13-16. Environmental Isotope Geochemistry, Vol. 1, The Terrestrial Environment, A: Amsterdam, The Loss, R.D., de Laeter, J.R., Rosman, K.J.R., Benjamin, Netherlands, Elsevier Scientific Publishing Co., p. T.M., Curtis, D.B., Gancarz, A.J., Delmore, I.E., 407-433. and Maeck, W.J., 1988, The Oklo natural reactors: cumulative fission yields and nuclear characteristics Li, W., Ni, B., Jin, D., and Chang, T.L., 1988, of reactor zone 9: Earth Planetary Science Letters, v. Measurement of the absolute abundance of oxygen- 89, p. 193-206. 17 in V-SMOW: Kexue Tongbao, v. 33, p. 1610- 1613. Loss, R.D., Rosman, K.J.R., de Laeter, J.R., Curtis, D.B., Benjamin, T.M., Gancarz, A.J., Maeck, Li, Y., Ding, T., and Defang, W., 1995, Experimental W.J., and Delmore, J.E., 1989, Fission product study of silicon isotope dynamic fractionation and its retentivity in peripheral rocks at the Oklo natural application in geology: Chinese Journal of fission reactors, Gabon: Chemical Geology, v. 76, Geochemistry, v. 14, p. 212-219. p. 71-84. Libby, L.M., and Pandolfi, L.J., 1974, Temperature Lowenstam, H.A., and Epstein, S., 1957, On the origin dependence of isotope ratios in tree rings: of sedimentary aragonite needles of the Great Proceedings of the National Academy of Sciences of Bahama Bank: Journal of Geology, v. 65, p. 364- the United States of America, v. 71, p. 2482-2486. 375. Lindau, C.W., and Spalding, R.F., 1984, Major Lu, D.L., and Wan, G.J., 1992, The application of procedural discrepancies in soil extracted nitrate silicon isotopes (<530Si) in a study on the material levels and nitrogen isotopic values: Ground Water, source of gold mineralization (in Chinese): Geology v. 22, p. 273-278. and Exploration, v. 28, p. 28-31. Liu, W.G., Xiao, Y.K., Wang, Q.Z., Qi, H.P., Wang, Magenheim, A.J., Spivack, A.J., Michael, P.J., and Y.H., Zhou, Y.M., and Shirodkar, P.V., 1997, Gieskes, J.M., 1995, Chlorine stable isotope Chlorine isotopic geochemistry of salt lakes in the composition of the oceanic crust: Implications for Qaidam Basin, China: Chemical Geology, v. 136, p. Earth's distribution of chlorine: Earth Planetary 271-279. Science Letters, v. 131, p. 427-432. Long, A., Eastoe, C.J., Kaufmann, R.S., Martin, J.G., Makhnach, A., Mikhajlov, N., Shimanovich, V., and Wirt, L., and Finley, J.B., 1993, High-precision Kolosov, L, 1994, Carbon and oxygen isotopic measurement of chlorine stable isotope ratios: composition of carbonates from saliferous deposits Geochimica et Cosmochimica Acta, v. 57, p. 2907- of the Pripyat Trough, Belarus: Sedimentary 2912. Geology, v. 94, p. 85-96. 87 Marechal, C.N., Telouk, P., and Albarede, F., 1999, Mermelengas, N., Rosman, K.J.R., and de Laeter, J.R., Precise analysis of copper and zinc isotopic 1981, The isotopic composition of palladium in compositions by plasma-source mass spectrometry: meteorites and terrestrial samples: International Chemical Geology, v. 156, p. 251-273. Journal Mass Spectrometry Ion Physics, v. 37, p. 1- 11. Mariotti, A., 1983, Atmospheric nitrogen is a reliable standard for natural 15N abundance measurements: Merritt, D.A., Hayes, J.M., and Des Marais, D.J., Nature, v. 303, p. 685-687. 1995, Carbon isotopic analysis of atmospheric methane by isotope-ratio-monitoring gas Mariotti, A., Lancelot, C., and Billen, G., 1984, Natural chromatography-mass spectrometry: Journal isotopic composition of nitrogen as a tracer of origin Geophysical Research, v. 100D1, p. 1317-1326. for suspended organic matter in the Scheldt estuary: Geochimica et Cosmochimica Acta, v. 48, p. 549- Michalski, G., and Thiemens, M.H., 2000, Mass 555. independent fractionation in nitrate aerosols (abstract): EOS, Transactions of the American Mariotti, A., Landreau, A., and Simon, B., 1988, N Geophysical Union, v. 81, p. F120. isotope biogeochemistry and natural denitrification process in groundwater Application to the chalk Misselhorn, and Grafahrend, W., 1990, aquifer of northern France: Geochimica et Rohstoffnachweis bei hochgereinigtem Alkohol: Die Cosmochimica Acta, v. 52, p. 1869-1878. Branntweinwirtschaft, v. 130, p. 70-73. Martin, G.J., Guillou, C., Martin, M.L., Cabanis, M.- Misselhorn, K., Bruckner, H., Miiftig-Zufika, M., and T., and Aerny, J., 1988, Natural factors of isotope Grafahrend, W., 1983, Nachweis des Rohstoffs bei fractionation and the characterization of wines: hockrektifiziertem Alkohol: Die Journal of Agriculture and Food Chemistry, v. 36, p. Branntweinwirtschaft, v. 123, p. 162-170. 316-322. Mitchell, R.H., 1989, Aspects of the petrology of Marty, B., Gunnlaugsson, £., Jambon, A., Oskarsson, kimberlites and lamproites: Some definitions and N., Ozima, M., Pineau, F., and Torssander, P., distinctions: Kimberlites and Related Rocks, v. 1, p. 1991, Gas geochemistry of geothermal fluids, the 7-45. Hengill area, southwest rift zone, Iceland: Chemical Geology, v. 91, p. 207-225. Mizutani, H., Hasegawa, H., and Wada, E., 1986, High nitrogen isotope ratio for soils of seabird rookeries: Mattey, D.P., Carr, L.P., Carr, R.H., Wright, I.P., and Biogeochemistry, v. 2, p. 221-247. Pillinger, C.T., 1985, Carbon and nitrogen in the deep Earth: Workshop on the early Earth: the Mizutani, Y., and Rafter, T.A., 1969, Oxygen isotopic interval from accretion to the older Archean: composition of sulphates Part 5: New Zealand Houston, Lunar and Planetary Institute Technical Journal of Science, v. 12, p. 69-80. Report, v. 85-01, p. 59-61. Molini-Velsko, C., Mayeda, T.L, and Clayton, R.N., Mayne, K.I., 1957, Natural variations in the nitrogen 1986, Isotopic composition of silicon in meteorites: isotope abundance ratio in igneous rocks: Geochimica et Cosmochimica Acta, v. 50, p. 2719- Geochimica et Cosmochimica Acta, v. 12, p. 185- 2726. 189. Mook, W.G., 1986, 13C in atmospheric CO2: Netherlands McKibben, M.A., and Eldridge, C.S., 1994, S isotopic Journal of Sea Research, v. 20, p. 211-223. effects in sulfur transformation: SHRIMP microanalysis of <534S zoning in pyrite from Moore, H., 1974, Isotopic measurement of atmospheric sedimentary and hydrothermal settings, Paper 101 nitrogen compounds: Tellus, v. 26B, p. 169-174. of ACS Division of Geochemistry, 208th ACS National Meeting, Washington, D.C., Aug. 21-25, ___ 1977, The isotopic composition of ammonia, 1994. nitrogen dioxide, and nitrate in the atmosphere: Atmospheric Environment, v. 11, p. 1239-1243. Meijer, H.A.J., and Li, W.J., 1998, The use of electrolysis for accurate <517O and <518O isotope Moore, L.J., and Machlan, L.A., 1972, High accuracy measurements in water: Isotopes Environmental determination of calcium in blood serum by isotope Health Studies, v. 34, p. 349-369. dilution mass spectrometry: Analytical Chemistry, v. _ 1999b, Certificate of Analysis, Standard Reference 44, p. 2291-2296. Material 952 Enriched Boric Acid Standard: Gaithersburg, Maryland, National Institute Standards Moore, L.J., Machlan, L.A., Shields, W.R., and and Technology, 2 p. Garner, E.L., 1974, Internal normalization techniques for high accuracy isotope dilution _ 2001, Certificate of Analysis, Standard Reference analyses: application to molybdenum and nickel in Material 975a Isotopic Standard for Chlorine: Standard Reference Materials: Analytical Chemistry, Gaithersburg, Maryland, National Institute Standards v. 46, p. 1082-1089. and Technology, 2 p. Murata, K.J., Friedman, I., and Madsen, B.M., 1969, Nomura, M., Kanzaki, T., Ozawa, T., Okamoto, M., Isotopic composition of diagenetic carbonates in and Kakihana, H., 1982, Boron isotopic marine Miocene Formations of California and composition of fumarolic condensates from some Oregon: U.S. Geological Survey Professional Paper volcanoes in Japanese island arcs: Geochimica et 614-B, p. B1-B24. Cosmochimica Acta, v. 46, p. 2403-2406. Nagler, T.F., Eisenhauer, A., Miiller, A., Hemleben, C., Norman, A.L., and Krouse, H.R., 1992, Stable isotope and Kramers, J., 2000, The c^Ca-temperature studies of atmospheric sulphur: Comparison of calibration on fossil and cultured Globigerinoides Calgary, Canada and Bermuda, Paper IU-8.01, in sacculifer. New tool for reconstruction of past sea Atmospheric Chemistry; Papers from the 9th World surface temperatures: Geochemistry, Geophysics, Clean Air Congress. Vol. 2, Critical Issues in the Geosystems, v. 1, Paper number 2000GC000091, Global Environment: Pittsburgh, Pennsylvania, Air published September 19, 2000. and Waste Management Association, 16 p. Nakamura, K., Schoeller, D.A., Winkler, F.J., and Notsu, K., Suigiyama, K., Hosoe, M., Uemura, A., Schmidt, H.-L., 1982, Geographical variations in Shimoike, Y., Tsunomori, F., and Hernandez, the carbon isotope composition of the diet and hair P.A., 2001, Diffuse C02 flux from Iwojima Volcano in contemporary man, Biomedical Mass of the Izu-Ogasawara Arc, Japan, in Eleventh Spectrometry, v. 9, p. 390-394. Annual V.M. Goldschmidt Conference, Abstract 3224: LPI Contribution No. 1088, Lunar and Nielsen, H., 1991, Anthropogenic sulphur in the Planetary Institute, Houston (CD-ROM). environment, in Krouse, H.R, and Grinenko, V.A., eds., Stable Isotopes: Natural and Anthropogenic Oeschger, H., and Siegenthaler, U., 1978, The dynamics Sulphur in the Environment: New York, John Wiley of the carbon cycle as revealed by isotope studies, in and Sons, p. 65-67. Williams, J., ed., Carbon Dioxide, Climate and Society: Oxford, Pergamon Press, p. 45-61. Nissenbaum, A., Presley, B.J., and Kaplan, I.R., 1972, Early diagenesis in a reducing fjord, Saanich Inlet, O'Leary, M.H., 1988, Carbon isotopes in photosynthesis: British Columbia I. Chemical and isotopic changes Bioscience, v. 38, p. 328-336. in major components of interstitial water: Geochimica et Cosmochimica Acta, v. 36, p. 1007- O'Neil, J.R., and Barnes, I., 1971, 13C and 18O 1027. compositions in some fresh-water carbonates associated with ultramafic rocks and serpentinites: NIST, 1992, Report of Investigation, Reference Materials Western United States: Geochimica et 8553-8557: Gaithersburg, Maryland, National Cosmochimica Acta, v. 35, p. 687-697. Institute Standards and Technology, 2 p. Oremland, R.S., and King, G.M., 1989, Methanogenesis _ 1998, Report of Investigation, Reference Materials in hypersaline environments, in Cohen, Y., and 8562-8564: Gaithersburg, Maryland, National Rosenberg, E., eds., Microbial Mats, Physiological Institute Standards and Technology, 4 p. Ecology of Benthic Microbial Communities: American Society for Microbiology, Chapter 16, p. _ 1999a, Certificate of Analysis, Standard Reference 180-190. Material 951 Boric Acid Standard: Gaithersburg, Maryland, National Institute Standards and Oremland, R.S., Miller, L.G., and Whiticar, M.J., Technology, 2 p. 1988a, Sources and flux of natural gases from Mono Lake, California: Geochimica et Cosmochimica Acta, v. 51, p. 2915-2929. 89 Oremland, R.S., Whiticar, M.J., Strohmaier, F.E., and variability of N2O emissions from tropical forest Kiene, R.P., 1988b, Bacterial methane formation soils: Global Biogeochemical Cycles, v. 14, p. 525- from reduced, ethylated sulfur compounds in anoxic 535. sediments: Geochimica et Cosmochimica Acta, v. Platzner, I., and Degani, N., 1990, Fractionation of 52, p. 1895-1904. stable calcium isotopes in tissues of date palm trees: Biomedical and Environmental Mass Spectrometry, Ostrom, N., 1992, Stable isotopic variation in particulate v. 19, p. 822-824. organic matter and dissolved inorganic compounds in a northern fjord: Implications for present and Polizzotto, M.L., Sharma, M., Anbar, A.D., 2000, Fe past environments: Ph.D. Dissertation, Memorial isotopes in deep-sea hydrotherrnal fluids (abstract): University of Newfoundland, Canada, 379 p. EOS, Transactions of the American Geophysical Union, v. 81, p. F179. Owens, N.J.P., 1987, Natural variations in 15N in the marine environment: Advances in Marine Biology, Qi, H.P., Coplen, T.B., Wang, Q.Zh., and Wang, Y.H., v. 24, p. 389-451. 1997b, Unnatural isotopic composition of lithium reagents: Analytical Chemistry, v. 69, p. 4076- Palin, J.M., and Rye, D.M., 1987, 13C/12C-18O/16O 4078. systematics of thin marbles in the Wepawaug schist, South-Central Connecticut: Geological Society of Qi, H.P., Taylor, P.D.P., Berglund, M., and De Bievre, America (Abstracts with Programs), v. 19, p. 798. P., 1997a, Calibrated measurements of the isotopic composition and atomic weight of the natural Li Palmer, M.R., and Sturchio, N.C., 1990, The boron isotopic reference material IRMM-016: International isotope systematics of the Yellowstone National Park Journal of Mass Spectrometry and Ion Processes, v. (Wyoming) hydrotherrnal system: A reconnaissance: 171, p. 263-268. Geochimica et Cosmochimica Acta, v. 54, p. 2811- 2815. Quay, P., Stutsnian, J., Wilbur, D., Snover, A., Dlugokencky, E., and Brown, T., 1999, The Parr, R.M., and Clements, S.A., 1991, Intercomparison isotopic composition of atmospheric methane: of enriched stable isotope reference materials for Global Biogeochemical Cycles, v. 13, p. 445-461. medical and biological studies: Vienna, Austria, International Atomic Energy Agency, NAHRES-5, Rafter, T.A., Kaplan, I.R., and Holston, J.R., 1960, 31 p. Sulphur isotopic variations in nature 7. Sulphur isotopic measurements on sulphur and sulphates in Parada, C.B., Long, A., and Davis, S.N., 1983, New Zealand geothermal and volcanic areas: New Stable-isotopic composition of soil carbon dioxide in Zealand Journal of Science, v. 3, 209-218. the Tucson Basin, Arizona, U.S.A: Isotope Geoscience, v. 1, 219-236. Rahn, T. and Wahlen, M., 2000, A reassessment of the global isotopic budget of atmospheric nitrous oxide: Paull, C.K., Jull, A.J.T., Toolin, L.J., Linick, T., 1985, Global Biogeochemical Cycles, v. 14, p. 537-543. Stable isotope evidence of chemosynthesis in an abyssal seep community: Nature, v. 317, p. 709- Ransom, B., Spivack, A.J., and Kastner, M., 1995, 711. Stable Cl isotopes in subduction-zone pore waters: Implications for fluid-rock reactions and the cycling Paull, C.K., Martens, C.S., Chanton, J.P., Neumann, of chlorine: Geology, v. 23, p. 715-718. A.C., Coston, J., Jull, A.J.T., and Toolin, L.J., 1989, Old carbon in living organisms and young Rashid, K., 1978, Selenium isotope fractionation during CaCOs cements from Abyssal brines seeps: Nature, chemical and microbiological selenite reduction: v. 342, p. 166-168. University of Calgary, Ph.D. thesis, 109 p. Peiser, H.S., Holden, N.E., De Bievre, P., Barnes, I.L., Rashid, K., and Krouse, H.R., 1985, Selenium isotopic Hagemann, R., de Laeter, J.R., Murphy, T.J., fractionation during SeOs2 reduction to Se° and Roth, E., Shima, M., and Thode, H.G., 1984, HiSe: Canadian Journal Chemistry, v. 63, p. 3195- Element by element review of their atomic weights: 3199. Pure and Applied Chemistry, v. 59, p. 695-768. Rau, G.H., 1981, Hydrothermal vent clam and tube worm Perez, T., Trumbore, S.E., Tyler, S.C., Davidson, E.A., 13C/12C: further evidence of nonphotosynthetic food Keller, M., and DeCamargo, P.B., 2000, Isotopic source: Science, v. 213, p. 338-339. 90 Rauschenbach, P., Simon, H., Stickler, W., and Moser, Rightmire, C.T., and Harishaw, B.B., 1973, Relationship H.j 1979, Vergleich der deuterium- und kohlenstoff- between the carbon isotope composition of soil COa 13-gehalte in fermentations- und syntheseethanol: Z. and dissolved carbonate species in groundwater: Naturforsch, v. 34, p. 1-4. Water Resources Research, v. 9, p. 958-967. Redding, C., 1978, Hydrogen and carbon isotopes in Rossmann, A., Schmidt, H.-L., Hermann, A., and coals and kerogens: 4th International Conference on Ristow, R., 1998, Multielement stable isotope ratio Geochronology, Cosmochronology and Isotope analysis of glycerol to determine its origin in wine: Geology, U.S. Geological Survey Open-File Report Zeitschrift fur Lebensmittel-Untersuchung und 78-701, p. 348-349. Forschung, A Food Research and Technology, v. 207, p. 237-243. Redfield, A.C., and Friedman, I., 1965, Factors affecting the distribution of deuterium in the ocean, Rosman, K.J.R., 1972, A survey of the isotopic and Symposium on Marine Geochemistry: Univ. Rhode elemental abundance of zinc: Geochimica et Island, Occasional Publication, v. 3, p. 149-169. Cosmochimica Acta, v. 36, p. 801-819. Rees, C.E., 1978, Sulphur isotope measurements using Rosman, K.J.R., de Laeter, J.R., and Kempt, N., 1989, SOa and SFe: Geochimica et Cosmochimica Acta, v. High-precision measurements of isotopic 42, p. 383-389. fractionation in palladium: International Journal Mass Spectrometry Ion Processes, v. 93, p. 107-114. Rees, C.E., Jenkins, W.J., and Monster, J., 1978, The sulphur isotopic composition of ocean water Rosman, K.J.R., and Taylor, P.D.P, 1998, Isotopic sulphate: Geochimica et Cosmochimica Acta, v. 42, compositions of the Elements 1997: Pure and p. 377-381. Applied Chemistry, v. 70, p. 217-235. Rees, C.E., and Thode, H.G., 1966, Selenium isotopic Roth, E., 1956, Composition isotopique de 1'hydrogene effects in the reduction of sodium selenite and of des gaz de Lacq: Academic des Sciences [Paris] sodium selenate: Canadian Journal Chemistry, v. 44, Comptes Rendus, v. 242, p. 3097-3100. p. 419-427. Rudnicki, M.D., Elder-field, H., and Spiro, B., 2001, Rehkamper, M., and Halliday, A.N., 1999, The precise Fractionation of sulfur isotopes during bacterial measurement of Tl isotopic compositions by MC- sulfate reduction in deep ocean sediments at elevated ICPMS: Application to the analysis of geological temperatures: Geochimica et Cosmochimica Acta, v. materials and meteorites: Geochimica et 65, p. 777-789. Cosmochimica Acta, v. 63, p. 935-944. Rumble, D., Bekker, A., Farquhar, J., Holland, H.D., Rehkamper, M., Frank, M., Halliday, A.N., and Hein, Hu, G., Maruyama, S., Ono, S., Ohmoto, H., J.R., 2001, Thallium isotope variations in Rosing, M., Ueno, Y., Wang, P., and Wing, B.A., ferromanganese crusts (abstract): European Union 2002, Geologic age distribution of sulfur isotope of Geosciences, 11 th biannual symposium, anomalies: Data from a new UV and IR laser Strassbourg, France, Book of Abstracts, p. 689. microprobe (abstract): EOS, Transactions of the American Geophysical Union, Spring Meeting Remaud, G.S., Martin, Y-L., Martin, G.G., Naulet, N., Supplement Abstract V41A-02, v. 83, p. S373. and Martin, G.J., 1997, Authentication of mustard oils by combined stable isotope analysis (SNIF-NMR Russell, W.A., Papanastassiou, D.A., and Tombrelo, and IRMS): Journal of Agriculture and Food T.A., 1978, Ca isotope fractionation on the Earth Chemistry, v. 45, p. 1844-1848. and other solar system materials: Geochimica et Cosmochimica Acta, v. 42, p. 1075-1090. Rigby, D., and Batts, B.D., 1986, The isotopic composition of nitrogen in Australian coals and oil Sakai, H., 1971, Sulfur and oxygen isotopic study of shales: Chemical Geology, v. 58, p. 273-282. barite concretions from banks in the Japan Sea off the Northeast Honshu, Japan: Geochemical Journal, Rightmire, C.T., 1978, Seasonal variation in Pco2 and v. 5, p. 79-93. 13C content of soil atmosphere: Water Resources Research, v. 14, p. 691-692. Schauble, E.A., Rossman, G.R., and Taylor, Jr., H.P., 2001, Theoretical estimates of equilibrium Fe-isotope fractionations from vibrational spectroscopy: 91 Geochimica et Cosmochimica Acta, v. 65, p. 2487- Shearer, G.B., Kohl, D.H., and Commoner, B., 1974, 2497. The precision of determinations of the natural abundance of nitrogen-15 in soils, fertilizers, and Schidlowski, M., 1987, Application of stable carbon shelf chemicals: Soil Science, v. 118, p. 308-316. isotopes to early biochemical evolution on Earth: Annual Reviews of Earth Planetary Science, v. 15, Shearer, G.B., and Legg, J.O., 1975, Variations in the p. 47-72. natural abundance of 15N of wheat plants in relation to fertilizer nitrogen applications: Soil Science of Schiegl, W.E., 1972, Deuterium Content of Peat as a America Society Proceedings, v. 39, p. 896-901. Paleoclimatic Recorder: Science, v. 175, p. 512-513. Shemesh, A., Kolodny, Y., and Boaz, L., 1983, Oxygen Schiegl, W.E., and Vogel, J.C., 1970, Deuterium content isotope variations in phosphate of biogenic apatites, of organic matter: Earth Planetary Science Letters, II. Phosphorite rocks: Earth Planetary Science v. 7, p. 307-313. Letters, v. 64, p. 405-416. Schmidt, H.-L., Werner, R.A., and Rossmann, A., Shields, W.R., Goldich, S.S., Garner, E.L., and 2001, 18O pattern and biosynthesis of natural plant Murphy, T.J., 1965, Natural variations in the products: Phytochemistry, v. 58, p. 9-32. abundance ratio and the atomic weight of copper: Journal Geophysical Research, v. 70, p. 479-491. Schoell, M., 1980, The hydrogen and carbon isotopic composition of methane from natural gases of Shields, W.R., Murphy, T.J., Catanzaro, E.J., and various origins: Geochimica et Cosmochimica Acta, Garner, E.L., 1966, Absolute isotopic abundance v. 44, p. 649-661. ratios and the atomic weight of a reference sample of chromium: Journal Research National Bureau of ___ 1988, ed., Origin of methane in the Earth: Standards (U.S.), v. 70A, p. 193-197. Chemical Geology, v. 71, 265 p. Shields, W.R., Murphy, T.J., and Garner, E.L., 1964, Schroeder, R.A., Setmire, J.G., and Densmore, J.N., Absolute isotopic abundance ratios and the atomic 1991, Use of stable isotopes, tritium, soluble salts, weight of a reference sample of copper: Journal and redox-sensitive elements to distinguish ground Research National Bureau Standards (U.S.), v. 68A, water from irrigation water in the Salton Sea basin, p. 593-599. in Ritter, W.F., ed., Irrigation and Drainage: New York, American Society of Civil Engineers, p. 524- Shields, W.R., Murphy, T.J., Garner, E.L., and 530. Dibeler, V.H., 1962, Absolute isotopic abundance ratios and the atomic weight of chlorine: Journal Schutze, H., Strauch, G., and Wetzel, K., 1982, Stable American Chemical Society, v. 84, p. 1519-1522. isotope investigations in Antarctica, in Schmidt, H.- L., and others, eds., Stable Isotopes, Analytical Shima, M., 1962, Boron in meteorites: Journal Chemistry Symposia Series, Proceedings of the 4th Geophysical Research, v. 67, p. 4521-4523. International Conference, Julich: Amsterdam, The Netherlands, Elsevier Scientific Publishing Co., p. ___ 1963, Geochemical study of boron isotopes: 121-126. Geochimica et Cosmochimica Acta, v. 27, p. 911- 913. Schwarcz, H.P., 1969, Carbon, in Wedepohl, K.H., ed., Handbook of Geochemistry: Berlin, Springer- ___ 1964, The isotopic composition of magnesium in Verlag, Section B-I, The Stable Isotopes of Carbon, terrestrial samples: Bulletin Chemical Society of p. 6-B-1-6-B-15. Japan, v. 37, p. 284-285. Schwarcz, H.P., Agyei, F.K., and McMullen, C.C., Shima, M., Rees, C., and Thode, H.G., 1978, The 1969, Boron isotopic fractionation during clay isotopic composition and atomic weight of adsorption from sea-water: Earth Planetary Science palladium: Canadian Journal Physics, v. 56, p. Letters, v. 6, p. 1-5. 1333-1339. Seiler, W., 1974, The cycle of atmospheric CO: Tellus, Siebert, C., Nagler, T.F., and Kramers, J.D., 2001 a, v. 26, p. 116-135. Determination of molybdenum isotope fractionation by double-spike multicollector inductively coupled plasma mass spectrometry: Geochemistry, 92 Geophysics, Geosystems, v. 2, paper number burning: Global Biogeochemical Cycles, v. 14, p. 2000GC000124, 16 p. 11-24. Siebert, C., Nagler, T.F., von Blankenburg, F., and Sofer, Z., 1984, Stable carbon isotope compositions of Kramers, J.D., 2001b, Constant molybdenum crude oils: Application to source depositional isotope composition of ocean water and Fe-Mn environments and petroleum alteration: The crusts for the last 70 Myr (abstract): EOS, American Association of Petroleum Geologists Transactions of the American Geophysical Union, v. Bulletin, v. 68, No. 1, p. 31-49. 82, p. F1324-F1325. Spicuzza, M.J., Valley, J.W., Kohn, M.J., Girard, J.P., Skulan, J., and DePaolo, D.J., 1999, Calcium isotope and Fouillac, A.M., 1998, The rapid heating, fractionation between soft and mineralized tissues as defocused beam technique: a COi-laser-based a monitor of calcium use in vertebrates: method for highly precise and accurate determination Proclamations National Academy Science, v. 96, p. of <518O values of quartz: Chemical Geology, v. 144, 13709-13713. p. 195-203. Skulan, J., DePaolo, D.J., and Owens, T.L., 1997, Spivack, A.J., 1986, Boron isotope geochemistry, Ph.D. Biological control of calcium isotopic abundances in dissertation, Massachusetts Institute of the global calcium cycle: Geochimica et Technology/Woods Hole Oceanographic Institution, Cosmochimica Acta, v. 61, p. 2505-2510. Joint Program in Oceanography, 184 p. Slatkin, D.N., Friedman, L., Irsa, A.P., and Micca, Spivack, A.J., and Edmond, J.M., 1987, Boron isotope P.L., 1985, The stability of DNA in human exchange between seawater and the oceanic crust: cerebellar neurons: Science, v. 228, p. 1002-1004. Geochimica et Cosmochimica Acta, v. 51, p. 1033- 1043. Smejkal, V., Cook, F.D., and Krouse, H.R., 1971, Studies of sulfur and carbon isotope fractionation Stallard, R.F., and Edmond, J.M., 1983, Geochemistry with microorganisms isolated from springs in of the Amazon 2. The influence of geology and Western Canada: Geochimica et Cosmochimica weathering environment on the dissolved load: Acta, v. 35, p. 787-800. Journal Geophysical Research, v. 88, p. 9671-9688. Smith, B.N., and Turner, B.L., 1975, Distribution of Sternberg, L., 1988, D/H Ratios of Environmental Water Kranz syndrome among Asteraceae: American Recorded by D/H Ratios of Plant Lipids: Nature, v. Journal Botany, v. 62, p. 541-545. 333, p. 59-61. Smith, C.L., Rosman, K.J.R., and de Laeter, J.R., ___ 1989, Oxygen and hydrogen isotope ratios in plant 1978, The isotopic composition of tellurium, cellulose: Mechanism and applications, in Rundell, International Journal Mass Spectrometry Ion Physics, P.W., Ehleringer, J.R., and Nagy, K.A., eds., Stable v. 28, p. 7-17. Isotopes in Ecological Research, Ecological Studies 68: New York, Springer Verlag, p. 124-141. Smith, J.W., and Pallasser, R.J., 1996, Microbial origin of Australian coalbed methane: American Sternberg, L., DeNiro, M.J., and Johnson, H.B., 1984, Association of Petroleum Geologists Bulletin, v. 80, Isotope ratios of cellulose from plants having p. 891-897. different photosynthetic pathways: Plant Physiology, v. 74, p. 557-561. Smith, R.L., Howes, B.L., and Duff, J.H., 1991, Denitrification in nitrate-contaminated groundwater: Stevens, C.M., Krout, L., Walling, D., Venters, A., occurrence in steep vertical geochemical gradients: Engelkemeir, A., and Ross, L.E., 1972, The Geochimica et Cosmochimica Acta, v. 55, p. 1815- isotopic composition of atmospheric carbon 1825. monoxide: Earth Planetary Science Letters, v. 16, p. 147-165. Smithers, M.R., and Krouse, H.R., 1968, Tellurium isotopic fractionation study: Canadian Journal Stichler, W., 1995, Interlaboratory comparison of new Chemistry, v. 46, p. 583-591. materials for carbon and oxygen isotope ratio measurements, in Reference and intercomparison Snover, A.K., Quay, P.D., and Hao, W.M., 2000, The materials for stable isotopes of light elements: D/H content of methane emitted from biomass 93 Vienna, Austria, International Atomic Energy Thiemens, M.H., 2001, The mass-independent ozone Agency, IAEA-TECDOC-825, p. 67-74. isotope effect: Science, v. 293, p. 226. Stroud, L., Meyer, T.O., and Emerson, D.E., 1967, Thiemens, M.H., Jackson, T.L., and Brenninkmeijer, Isotopic abundance of neon, argon, and nitrogen in C.A.M., 1995, Observation of a mass independent natural gases: U.S. Department of the Interior, oxygen isotopic composition in terrestrial Bureau of Mines, Report of Investigation 6936, 27 stratospheric CC»2, the link to ozone chemistry, and P- the possible occurrence in the Marian atmosphere: Geophysical Research Letters, v. 22, p. 255-257. Suwa, K., Oana, S., Wada, H., and Osaki, S., 1975, Isotope geochemistry and petrology of African Thiemens, M.H., Jackson, T.L., Mauersberger, K., carbonatites: Physics and Chemistry of the Earth, v. Schueler, B., and Morton, J., 1991, Oxygen 9, p. 735-745. isotope fractionation in stratospheric COi: Geophysical Research Letters, v. 18, p. 669-672. Svec, H.J., and Anderson Jr., A.R., 1965, The absolute abundance of the lithium isotopes in natural sources: Thiemens, M.H., and Trogler, W.C., 1991, Nylon Geochimica et Cosmochimica Acta, v. 29, p. 633- production: Unknown source of atmospheric nitrous 641. oxide: Science, v. 251, p. 932-934. Swihart, G.H., and Moore, P.B., 1989, A reconnaissance Thode, H.G., Harrison, A.G., and Monster, J., 1960, of the boron isotopic composition of tourmaline: Sulphur isotope fractionation in early diagenesis of Geochimica et Cosmochimica Acta, v. 53, p. 911- recent sediments of North-East Venezuela: Bulletin 916. of the American Association of Petroleum Geologists, v. 44, p. 1809-1817. Swihart, G.H., Moore, P.B., and Callis, E.L., 1986, Boron isotopic composition of marine and Thode, H.G., Monster, J., and Dunford, H.B., 1961, nonmarine evaporite berates: Geochimica et Sulphur isotope geochemistry: Geochimica et Cosmochimica Acta, v. 50, p. 1297-1301. Cosmochimica Acta, v. 25, p. 159-174. Tamers, M.A., 1970, Validity of radiocarbon dates on Tieszen, L.L., and Boutton, T.W., 1988, Stable carbon terrestrial snail shells: American Antiquity, v. 35, p. isotopes in terrestrial ecosystem research, in Rundel, 94-100. P.W., and others, eds., Stable Isotopes in Ecological Research: New York, Springer-Verlag, p. 167-195. Tanaka, N., and Rye, D., 1991, Chlorine in the stratosphere: Nature, v. 353, p. 707. Tilles, D., 1961, Variations of silicon isotope ratios in a zoned pegmatite: Journal Geophysical Research, v. Tans, P., 1981, 13C/12C of industrial CO2, in Bolin, B., 66, p. 3015-3020. ed., Carbon Cycle Modelling: New York, John Wiley & Sons, p. 121-127. Tomascak, P.B., Lynton, S.J., Walker, R.J., and Krogstad, E.J., 1995, Li isotope geochemistry of Taylor, B., 1986, Magmatic volatiles: Isotopic variation Tin Mountain pegmatite, Black Hills, South Dakota, of C, H, and S, in Valley, J.W., and others, eds., in Brown, M., and Piccoli, P.M., eds., The origin of Stable Isotopes in High Temperature Geological granites and related rocks: U.S. Geological Survey Processes: Mineralogical Society of America, Circular 1129, p. 151-152. Reviews in Mineralogy, v. 16, p. 185-225. Tonarini, S., Pennisi, M., Adorni-Braccesi, A., Dini, A., Taylor, H.P., Jr., 1968, The oxygen isotope Ferrara, G., Gonfiantini, R., Griming, M., and geochemistry of igneous rocks: Contributions Wiedenbeck, M., in press, Intercomparison of Mineralogy and Petrology, v. 19, 1-71. boron stable isotope measurements: Geostandards Newsletter. Taylor, P.D.P., Maeck, R, and De Bievre, P., 1992, Determination of the absolute isotopic composition Trumbull, R.B., and Chaussidon, M., 1999, Chemical and atomic weight of a reference sample of natural and boron isotopic composition of magmatic and iron: International Journal Mass Spectrometry Ion hydrothermal tourmalines from the Sinceni granite- Processes, v. 121, p. 111-125. pegmatite system in Swaziland: Chemical Geology, v. 153, p. 125-137. 94 Tse, R.S., Wong, S.C., and Yuen, C.P., 1980, Vanderpool, R.A., and Johnson, P.E., 1992, Boron Determination of deuterium/hydrogen ratios in isotope ratios in commercial produce and boron-10 natural waters by Fourier transform nuclear magnetic foliar and hydroponic enriched plants: Journal of resonance spectrometry: Analytical Chemistry, v. Agriculture and Food Chemistry, v. 40, p. 462-466. 52, p. 2445. Velinsky, D.J., Fogel, M.L., Todd, J.F., and Tebo, Ueda, S., Ogura, N., and Wada, E., 1991, Nitrogen B.M., 1991, Isotopic fractionation of dissolved stable isotope ratio of groundwater N2O: ammonium at the oxygen-hydrogen sulfide interface Geophysical Research Letters, v. 18, p. 1449-1452. in anoxic waters: Journal of Geophysical Research Letters, v. 18, p. 649-652. Valley, J.W., and Cole, D. R., 2001, eds., Stable Isotope Geochemistry: Mineralogical Society of America, Velinsky, D.J., Pennock, J.R., Sharp, J.H., Cifuentes, Reviews in Mineralogy & Geochemistry, v. 43, 662 L.A., and Fogel, M.L., 1989, Determination of the P- isotopic composition of ammonium-nitrogen at the natural abundance level from estuarine waters: Valley, J.W., and O'Neil, J.R., 1981, 13C/12C exchange Marine Chemistry, v. 26, p. 351-361. between calcite and graphite: a possible thermometer in Grenville marbles: Geochimica et Vengosh, A., Chivas, A.R., and McCulloch, M.T., Cosmochimica Acta, v. 45, p. 411-419. 1989, Direct determination of boron and chlorine isotopic compositions in geologic materials by Valley, J.W., Taylor, Jr., H.P., and O'Neil, J.R., 1986, negative thermal-ionization mass spectrometry: eds., Stable Isotopes in High Temperature Chemical Geology (Isotope Geoscience Section), v. Geological Processes: Mineralogical Society of 79, p. 333-343. America, Reviews in Mineralogy, v. 16, 570 p. Vengosh, A., Chivas, A.R., McCulloch, M.T., Valyayev, V.M., Grinchenko, Y.I., Yerokhin, V.Ye., Starinsky, A., and Kolodny, Y., 1991a, Boron Prokhorov, V.S., and Titkov, G.A., 1985, Isotopic isotope geochemistry of Australian salt lakes: composition of gases from mud volcanoes: Geochimica et Cosmochimica Acta, v. 55, p. 2591- Lithology and Mineral Resources (USSR), v. 20, p. 2606. 62-75. Vengosh, A., Kolodny, Y., Starinsky, A., Chivas, A.R., Van der Merwe, N.J., 1982, Carbon isotopes, and McCulloch, M.T., 1991b, Coprecipitation and photosynthesis, and archaeology: American isotopic fractionation of boron in modern biogenic Scientist, v. 70, p. 596-606. carbonates: Geochimica et Cosmochimica Acta, v. 55, p. 2901-2910. Van Stempvoort, D.R., and Krouse, H.R., 1994, Controls on d 1 8 O in sulfate: review of experimental Vengosh, A., Starinsky, A., Kolodny, Y., Chivas, A.R., data and applications to specific environments, in and Raab, M., 1992, Boron isotope variations Alpers, C.N., and Blowes, D.W., eds., during fractional evaporation of sea water: New Environmental Geochemistry of Sulfide Oxidation: constraints on the marine vs. nonmarine debate: American Chemical Society Symposium Series 55, Geology, v. 20, p. 799-802. p. 446-480. Veselovsky, N.V., Rabinovich, A.L., and Putintseva, van Everdingen, R.O., Shakur, M.A., and Krouse, V.S., 1969, Isotopic composition of sulfate ion sulfur H.R., 1982, Isotope geochemistry of dissolved, in water from the Kuma River and some of its precipitated, airborne, and fallout sulfur species tributaries: Gidrokhim Mater, v. 51, p. 112-119. associated with springs near Paige Mountain, Norman Range, N.W.T: Canadian Journal of Earth Vocke, R.D., Jr., Beary, E.S., and Walker, R.J., 1990, Sciences, v. 19, p. 1395-1407. High precision lithium isotope ratio measurements of samples from a variety of natural sources, in V.M. van Warmerdam, E.M., Frape, S.K., Aravena, R., Goldschmidt conference; program and abstracts: Drimmie, R.J., Flatt, H., and Cherry, J.A., 1995, Geochemical Society, p. 89. Stable chlorine and carbon isotope measurements of selected chlorinated organic solvents: Applied Vogel, J.C., Talma, A.S., and Heaton, T.H.E., 1981, Geochemistry, v. 10, p. 547-552. Gaseous nitrogen as evidence for denitrification in groundwater: Journal of Hydrology, v. 50, p. 191- 200. 95 Volynets, V.F., Zadorozhnyy, I.K., and Florenskiy, Weber, J.N., and Raup, D.M., 1966, Fractionation of the K.P., 1967, Isotopic composition of nitrogen in the Stable Isotopes of Carbon and Oxygen in Marine Earth's crust (in Russian): Geokhimiya, no. 5, p. Calcareous Organisms the Echinoidea: II. 587-592. Environmental and Genetic Factors: Geochimica et Cosmochimica Acta, v. 30, p. 705-736. Wachsmann, M., and Heumann, K.G., 1989, Selenium isotope ratio measurements with negative thermal Wenner, D.B., 1979, Hydrogen, oxygen and carbon ionization mass spectrometry using a silica gel isotopic evidence for the origin of rodingites in technique: Advances Mass Spectrometry, v. 11B, p. serpentinized ultramafic rocks: Geochimica et 1828-1829. Cosmochimica Acta v. 43, p. 603-614. ___ 1992, Negative thermal ionization of main group Werner, R.A., 1998, Entwicklung neuer Verfahren fur elements. Part 2, 6th group: Sulfur, selenium, die on-line 18O/16O- und 2H/1H- tellurium: International Journal of Mass Isotopenverhaltnismessung und ihre Anwendung zur Spectrometry and Ion Processes, v. 114, p. 209-220. Authentizitats- und Herkunftsbestimmung bei Naturstoffen: Ph.D. Thesis, Technische Universitat Wada, E., Shibata, R., and Torii, T., 1981, 15N Miinchen, Hieronymus Buchreproduktions GmbH, abundance in Antarctica: origin of soil nitrogen and Munich, Germany. ecological implications: Nature, v. 292, p. 327-329. Weyer, K.U., Krouse, H.R., and Horwood, W.C., 1979, Wahlen, M., 1993, The global methane cycle: Annual Investigation of regional geohydrology south of Reviews of Earth and Planetary Science, v. 21, p. Great Slave Lake, Canada, utilizing natural sulphur 407^26. and hydrogen isotope variations, in Isotope Hydrology 1978, Vol. 1: Vienna, Austria, Wahlen, M., and Yoshinari, T., 1985, Oxygen isotope International Atomic Energy Agency, p. 251-264. ratios in N2O from different environments: Nature, v. 313, p. 780-782. Winkler, F.J., 1984, Application of natural abundance stable isotope mass spectrometry in food control, in Walczyk, T., 2001, The potential of inorganic mass Frigerio, A., and Milon, H., eds., Chromatography spectrometry in mineral and trace element nutrition and Mass Spectrometry in Nutrition Science and research: Fresenius Journal of Analytical Chemistry, Food Safety: Amsterdam, The Netherlands, Elsevier v. 370, p. 444-453. Science Publishers, p. 173-190. Walder, A.J., and Freedman, P.A., 1992, Isotope ratio White, J.W.C., Cook, E.R., Lawrence, J.R., and measurements using a double focusing magnetic Broecker, W.S., 1985, The D/H ratios of sap in sector mass analyzer with an inductively coupled trees: Implications for water sources and tree ring plasma ion source: Journal of Analytical Atomic D/H ratios: Geochimica et Cosmochimica Acta, v. Spectrometry, v. 7, p. 571-575. 49, p. 237-246. Walker, E.C., Cuttitta, F., and Senftle, F.E., 1958, Whiticar, M.J., 1990, A geochemical perspective of Some natural variations in the relative abundance of natural gas and atmospheric methane, in Durand, B., copper isotopes: Geochimica et Cosmochimica Acta, and others, eds., Advances in Organic Geochemistry v. 15, p. 183-194. 1989: Organic Geochemistry, v. 16, p. 531-547. Wang, G., and Xiao, Y.K., 2000, Extraction and Whiticar, M.J., Faber, E., and Schoell, M., 1986, separation of boron in rock samples and its isotopic Biogenic methane formation in marine and determination by thermal ionization mass freshwater environments: CO2 reduction vs. acetate spectrometry (in Chinese): Rock and Mineral fermentation Isotope evidence: Geochimica et Analysis, v. 19, p. 169-172. Cosmochimica Acta, v. 50, p. 693-709. Wasserburg, G.J., Mazor, E., and Zartman, R.H., Whiticar, M.J., Grant, N., and Suess, E., 1999, 1963, Isotopic and chemical composition of some Characterization of methane formation, oxidation and terrestrial natural gases, in Geiss, J., and Goldberg, fluxes associated with cold seeps and hydrates at the E.D., eds., Earth and Science Meteoritics: Oregon Margin (abstract): EOS, Transactions of the Amsterdam, The Netherlands, North Holland, p. American Geophysical Union, v. 80, p. F510-F511. 219-240. 96 Whiticar, M.J., Hovland, M., Kastner, M., and Yapp, C.J., 1987a, A possible goethite-iron (III) Sample, J., 1995, Organic geochemistry of gases, carbonate solid solution and the determination of fluids, and hydrates at the Cascadia Accretionary CO2 partial pressures in low temperature geologic Margin, in Carson, B., and Westbrook, G., eds.: systems: Chemical Geology, v. 64, p. 259-268. Ocean Drilling Program Scientific Results, v. 146, p. 385-398. _ 1987b, Oxygen and hydrogen isotope variations among goethites (a-FeOOH) and the determination Wieser, M.E., and de Laeter, J.R., 2000, Thermal of paleotemperatures: Geochimica et Cosmochimica ionization mass spectrometry of molybdenum Acta, v. 51, p. 355-364. isotopes: International Journal of Mass Spectrometry, v. 197, p. 253-261. _ 1990, Oxygen isotopes in iron (III) oxides. 1. Mineral-water fractionation factors: Chemical Wieser, M.E., lyer, S.S., Krouse, H.R., and Cantagallo, Geology, v. 85, p. 329-335. M.I., 2001, Variations in the boron isotope composition of Coffea arabica beans: Applied _ 1993, The stable isotope geochemistry of low Geochemistry, v. 16, p. 317-322. temperature Fe(III) and Al "oxides" with implications for continental paleoclimate, in Swart, Williams, L.B., Hervig, R.L., Wieser, M.E., and P.K., and others, eds., Climate Change in Hutcheon, I., 2001, The influence of organic matter Continental Isotopic Records: Washington, D.C., on the boron isotope geochemistry of the gulf coast American Geophysical Union, Geophysical sedimentary basin, USA: Chemical Geology, v. 174, Monograph 78, p. 285-294. p. 445-461. Yapp, C.J., and Epstein, S., 1982, Climatic significance Williard, K.W.J., DeWalle, D.R., Edwards, P.J., and of the hydrogen isotope ratios in tree cellulose: Sharpe, W.E., 2001, 18O isotopic separation of Nature, v. 297, p. 636-639. stream nitrate sources in mid-Appalachian forested watersheds: Journal of Hydrology, v. 252, p. 174- Yoshida, N., and Matsuo, S., 1983, Nitrogen isotope 188. ratio of atmospheric N2O as a key to the global cycle of N2O: Geochemical Journal, v. 17, p. 231- Wu, S.Y., 1991, The submarine hydrothermal chimney of 239. the Mariana Trough and sediments in the Philippine Sea (in Chinese): Beijing, Oceanic Publishing Yoshida, N., Morimoto, H., Hirano, M., Koike, I., House, p. 58-63. Matsuo, S., Wada, E., Saino, T., and Hattori, A., 1989, Nitrification rates and 15N abundances of N2O Wulff, D., Batts, B.D., Krouse, H.R., and Jackson, S., and NOs" in the western North Pacific: Nature, v. 1999, Measurement of selenium isotope abundance 342, p. 895-897. variations by ICP-MS: Abstracts of the International Association of Geochemistry and Cosmochemistry, Yoshinari, T., Altabet, M.A., Naqvi, S.W.A., Codispoti, 3rd International Symposium Applied Isotope L., Jayakumar, A., Kuhland, M., and Devol, A., Geochemistry, Sept. 21-25, 1999, Orleans France, p. 1997, Nitrogen and oxygen isotopic composition of 41. N2O from suboxic waters of the eastern tropical North Pacific and the Arabian Sea measurement by Xiao, Y., Yin, D., Liu, W., Wang, Q., and Wei, H., continuous-flow isotope-ratio monitoring: Marine 2001, Boron isotope method for study of seawater Chemistry, v. 56, p. 253-264. intrusion: Science In China, v. 44 Supp., p. 62-71. You, C.-F., and Chan, L.-H., 1996, Precise Xiao, Y.K., Zhou, Y.M., Liu, W.G., Hong, A.S., Wang, determination of lithium isotopic composition in low Q.Z., Wei, H.Z., and Shirodkar, P.V., 2002a, The concentration natural samples: Geochimica et character of chlorine isotopic compositions in ocean Cosmochimica Acta, v. 60, p. 909-915. water (in Chinese): Geological Review, v. 48 (sup), in press. Yonge, C.J., and Krouse, H.R., 1987, The origin of sulphates in Castleguard Cave, Columbia Icefields, Xiao, Y.K., Zhou, Y., Wang, Q., Wei, H., Liu, W., and Canada: Chemical Geology (Isotope Geoscience Eastoe, C.J., 2002b, A secondary isotopic reference Section), v. 65, p. 427-433. material of chlorine from selected seawater: Chemical Geology, v. 182, p. 655-661. Yurtsever, Y., and Gat, J.R., 1981, Atmospheric water, in Stable Isotope Hydrology, Deuterium and 97 Oxygen-18 in the Water Cycle: Vienna, Austria, International Atomic Energy Agency, p. 103-142. Zak, K., and Skala, R., 1993, Carbon isotopic composition of whewellite (CaCiO^HiO) from different geological environments and its significance: Chemical Geology (Isotope Geoscience Section), v. 106, p. 123-131. Zhang, B.-L., Quemerais, B., Martin, M.L., Martin, G.J., and Williams, J.M., 1994, Determination of the natural deuterium distribution in glucose from plants having different photosynthetic pathways: Phytochemical Analysis, v. 5, p. 105-110. Zhang, Q.L. (Chang, T.L.) and Ding, T., 1989, Analysis of the reference material NBS-123 and the atomic weight of sulfur: Chinese Science Bulletin, v. 34, p. 1086-1089. Zhu, P., and Macdougall, D., 1998, Calcium isotopes in the marine environment and the oceanic calcium cycle: Geochimica et Cosmochimica Acta, v. 62, p. 1691-1698. Zhu, X.K., O'Nions, R.K., Guo, Y., Belshaw, N.S., and Rickard, D., 2000a, Determination of natural Cu-isotope variations by plasma-source mass spectrometry: implications for use as geochemical tracers: Chemical Geology, v. 163, p. 139-149. Zhu, X.K., O'Nions, R.K., Guo, Y., and Reynolds, B.C., 2000b, Secular variation of iron isotopes in North Atlantic Deep Water: Science, v. 287, p. 2000-2002. Zhu, X.K., O'Nions, R.K., Matthews, A.Guo, Y., and Williams, R.J.P., 2001, Mass fractionation of transition metal isotopes, in Eleventh Annual V.M. Goldschmidt Conference, Abstract 3745: LPI Contribution No. 1088, Lunar and Planetary Institute, Houston (CD-ROM). Zschiesche, M., 1972, Entwicklung probenchemischen Verfahren zur Bestimmung der isotopen Zusammensetzung des N aus Gasen, Gesteinen, und N-Lieferanten fur bakteriologische Modelluntersuchungen: Dissertation, Karl-Marx- Universitat, Leipzig, Germany, 76 p. Zyakun, A.M., Bondar, V.A., and Namsaraev, B.B., 1981, Fractionation of methane carbon isotopes by methane-oxidizing bacteria, in Forschungsheft C360, Reaktor der Bergakademie Freiberg: Leipzig, Germany, VEB Deutscher Verlag fur Grundstoff Industrie, p. 19-27. 98