Glass oxygen isotopes

Harmon and Hoefs (1995) have assembled a database consisting of 2,855 O-isotope analyses of Neogene volcanic rocks worldwide. They observed a 5%c variation in the 5 0-values of fresh basalts and glasses, which they have taken as evidence of significant oxygen isotope heterogeneities in the mantle sources of the basalts. This is documented in Fig. 3.8, which plots 8 0-values vs. Mg-numbers (Harmon and Hoefs 1995). 

Another experimental method to investigate diffusion is the so-called half-space method, in which the sample (e.g., rhyolitic glass with normal oxygen isotopes) is initially uniform with concentration C, but one surface (or all surfaces, as explained below) is brought into contact with a large reservoir (e.g., water vapor in which oxygen is all 0). The surface concentration of the sample is fixed to be constant, referred to as Cq. The duration is short so that some distance away from the surface, the concentration is unaffected by diffusion. Define the surface to be X = 0 and the sample to be at x > 0. This diffusion problem is the so-called halfspace or semi-infinite diffusion problem. 

Stolper E.M. and Epstein S. (1991) An experimental study of oxygen isotope partitioning between silica glass and C02 vapor. In Stable Isotope Geochemistry A Tribute to Samuel Epstein, Vol. 3 (ed. H.P. Taylor, J.R. O Neil, andI.R. Kaplan), pp. 35-51. Geochem. Soc. 

FIGURE 28 Oxygen isotopes in ancient glass. Oxygen, which consists mainly of a... 

Figure 15 Oxygen-isotopic compositions of individual minerals in (a) aluminum-rich chondrules from ordinary chondrites (Russell et at, 2000) and (h) CR carhonaceous chondrites (Krot et ah, 2002h). (c) Oxygen-isotopic compositions of individual minerals in the CAI-hearing chondmle 17 from Acfer 094 (data from Krot et al, 2003a) (Ahhreviations chd, chondmle cpx, clinopyroxene gl, glass hih, hihonite nph, nepheline ol, olivine opx, orthopyroxene pi, plagioclase px, pyroxene sp, spinel).

Crowe DE, Riciputi LR, Bezenek S, Ignatiev A (2001) Oxygen isotope and trace element zoning in hydrothermal garnets Windows into large-scale fluid flow. Geology 29 479-482 Davis KM (1994) The diffusion of water into silica glass at low temperature. PhD dissertation, Rensselaer Polytechnic Institute... 

Haul RAW, Dumbgen G (1962) Investigation of oxygen diffusion in Ti02, qtrartz and quartz glass by isotope exchange. Z Electrochem 66 636-641... 

Mazurin O, Streltsina M, Shvaiko-Shvaikovskaya T (1983) Handbook of Glass Data. Elsevier, Amsterdam McConnell JDC (1995) The role of water in oxygen isotope exchange in quartz. Earth Planet Sci Lett 136 97-107... 

Palin JM, Epstein S, StolperEM (1996) Oxygen isotope partitioning between rhyolitic glass/melt and CO2 An experimental study at 550-950°C and 1 bar. Geochim Cosmochim Acta 60 1963-1973 Palmer DA, Drummond SE (1986) Thermal decarboxylation of acetate. Part I. The kinetics and mechanism of reaction in aqueous solution. Geochim Cosmochim Acta 50 813-823... 

Figure 9. Oxygen isotope compositions of nominally fresh MORE glasses and whole-rocks. Unfilled boxes are data collected using conventional (resistance heated) fluorination methods between 1966 and 1993 filled boxes are data collected only on glass using laser-based methods. Where these two data types overlap, conventional fluorination data are shown as white-outlined boxes. Data sources Taylor (1968), Muehlenbachs and Clayton (1972), Pineau et al. (1976), Kyser et al. (1982), Muehlenbachs and Byerly (1982), Ito et al. (1987), Barrat et al. (1993), Harmon and Hoefs (1995) and references therein, Eiler et al. (2000b), and Eiler and Kitchen (unpublished data).

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