Oxygen isotope techniques

Ann McNichol is a Research Specialist at the National Ocean Sciences Accelerator Mass Spectrometry Facility at the Woods Hole Oceanographic Institution, which produces high-precision 14C measurements from small-volume samples. Dr. McNichol s research interests include the study and use of carbon, nitrogen, and oxygen isotope techniques to quantify bio-geochemical processes, the study of the fate of organic matter (both natu-... 

Fritz P, Drimmie RJ, Frape SK, O Shea K (1987) The isotopic composition of precipitation and groundwater. In Canada International Symposium on the Use of Isotope Techniques in Water Resources Development. IAEA Symposium, Vienna 299 539-550 Frumkin A, Ford DC, Schwarcz HP (1999) Continental oxygen isotopic record of the last 170,000 years in Jerasalem. (JuatRes 51 317-327... 

We can predict the oxygen and carbon isotopic compositions of the dolomite produced by this reaction path, using the techniques described in Chapter 19. Figure 25.4 shows the compositions of calcite and dolomite cements in the Lyons, as determined by Levandowski et al. (1973). The calcite and dolomite show broad ranges in oxygen isotopic content. The dolomite, however, spans a much narrower range in carbon isotopic composition than does the calcite. 

Oxygen isotopes were analyzed using the technique of Clayton and Mayeda (69). Data are presented using the standard 6 notation relative to Standard Mean Ocean Water (SMOW). 

Fortier SM, Cole DR, Wesolowski DJ, Riciputi LR, Paterson BA, Valley JW, Horita J (1995) Determination of the magnetite-water equilibrium oxygen isotope fractionation factor at 350°C a comparison of ion microprobe and laser fluorination techniques. Geochim Cosmochim Acta 59 3871-3875 Friedman I, O Neil JR (1977) Compilation of Stable Isotope Fractionation Factors of Geochemical Interest. US Geol Surv Prof Paper 440-KK... 

Dual isotope technique The technique uses two heavy isotopes, oxygen ( 0) and deuterium ( H). Water that contains these isotopes is prepared. The subject drinks a glass of this water, as part of a normal meal. Once equilibrated with body water, which occurs quickly, the content of in the water falls due to the production of unlabelled water from the oxidation of fuels. Similarly, the 02 content in the water also falls but the rate is greater than that of since the 02 equilibrates not only with the oxygen atoms in water but also with those in carbon dioxide. An equihbrium between water and carbon dioxide is rapidly estabhshed due to the activity of the enzyme carbonate dehydratase. 

In addition to oxygen isotopes, the volatile elements H, C, N, and S also show extremely large variations in isotope composition in meteorites. In recent years, most investigations have concentrated on the analyses of individual components with more and more sophisticated analytical techniques. 

Brand W (2002) Mass spectrometer hardware for analyzing stable isotope ratios. In P de Groot (ed.) Handbook of stable isotope analytical techniques. Elsevier, Amsterdam Brandriss ME, O Neil JR, Edlund MB, Stoermer EF (1998) Oxygen isotope fractionation between diatomaceous silica and water. Geochim Cosmochim Acta 62 1119-1125 Bremner JM, Keeney DR (1966) Determination and isotope ratio analysis of different forms of nitrogen in soils. III. Soil Sci Soc Am Proc 30 577-582 Brenninkmeijer CAM (1993) Measurement of the abundance of CO in the atmosphere and the and 0/ 0 ratio of atmospheric CO with applications in New Zealand and Australia. J Geophys Res 98 10595-10614... 

Schmidt M, Botz R, Stoffers P, Anders T, Bohrmann G (1997) Oxygen isotopes in marine diatoms a comparative study of analytical techniques and new results on the isotope composition of recent marine diatoms, Geochim Cosmochim Acta 61 2275-2280 Schmidt M, Botz R, Rickert D, Bohrmann G, Hall SR, Mann S (2001) Oxygen isotopes of marine diatoms and relations to opal-A maturation. Geochim Cosmochim Acta 65 201-211 Schmitt AD, StUle P, Vennemann T (2003) Variations of the Ca/ °Ca ratio in seawater during the past 24 milhon years evidence from 5 Ca and 5 0 values of Miocene phosphates. Geochim Cosmochim Acta 67 2607-2614... 

Vennemann TW, Fricke HC, Blake RE, O Neil JR, Colman A (2002) Oxygen isotope analysis of phosphates a comparison of techniques for analysis of AgsP04. Chem Geol 185 321-336 Vogel JC, Grootes PM, Mook WG (1970) Isotopic fractionation between gaseous and dissolved carbon dioxide. Z Physik 230 225-238... 

Wiechert U, Hoefs J (1995) An exdmer laser-based microanalytical preparation technique for in-situ oxygen isotope analysis of sUicate and oxide minerals. Geochim Cosmochim Acta 59 4093 101... 

With the improvement of analytical techniques, it is now possible to measure oxygen isotopic profiles in minerals. By analogy to the concepts of bulk mineral closure temperature versus closure temperature at every point in the interior of a mineral for the case of thermochronology, future theoretical development will need to clarify the concepts and meanings of Tc and Tae based on interior isotopic or elemental compositions of two contacting minerals. Furthermore, the principles of the above discussion may also be applied to elemental exchange reactions, such as Fe-Mg exchange between minerals. 

Isotopes of oxygen and hydrogen are useful tracers of water sources because they are constituents of the water molecule itself and because they are conservative in aquifers at near-surface temperatures. Isotopic techniques take advantage of the fact that lakes and their surrounding ground-water systems are usually isotopically distinct. Applications of stable isotopes for the study of lakes were first described by Dincer (10) and were discussed in several subsequent review articles (11-14). Most applications of isotopic techniques to lake systems are designed for the determination of water balances, nutrient-uptake studies, and paleotemperature reconstructions. 

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