Garnets oxygen isotopes

Valley, J.W., Kitchen, N., Kohn, M.J., Niendorf, C.R. and Spicuzza, M.J. 1995 UWG-2, a garnet standard for oxygen isotope ratios strategies for high precision and accuracy with laser heating. Geochimica et Cosmochimica Acta 59 5223-5231. 

The first and the simplest type is component exchange between phases without growth or dissolution of either phase. Examples include oxygen isotope exchange between two minerals, and Fe -Mg exchange between olivine and garnet or between olivine and melt. This is essentially a diffusion problem. 

Figure 3-30 An example of obtaining diffusivity (a) from mass exchange data with spheres using Equation 3-125 (Gas/melilite oxygen isotope exchange data of Hayashi and Muehlenbachs (1986)) and (b) using mass loss data from a single thin wafer using Equation 3-126 (garnet dehydration data of Wang et al. (1996)).

Large instrumental mass fractionations have been observed during measurements of oxygen isotope ratios on Fe-Mg-Ca garnets in SIMS.83 Part of this fractionation depends on crystal structure and mineral composition. 

Evidence of protracted growth history of skam garnet using SIMS oxygen isotope, trace element, and rare earth element data. Geol. Soc. Amer. Abstr. Prog. 1995. 

Because of the buffering effect of mantle olivine on the oxygen isotope composition of metasomatic fluids, oxygen isotopes are not, in most cases, effective tracers of mantle-fluid interaction (Mattey et al, 1994 Menzies and Chazot, 1995). One exception to this is the fluid-process that creates diamond. Comparison of the oxygen isotope compositions of garnets in typical... 

Ongley I. S., Basu A. R., and Kyser T. K. (1987) Oxygen isotopes in coexisting garnets, clinopyroxenes and phlogo-pites of Roberts Victor eclogites implications for petrogenesis and mantle metasomatism. Earth Planet. Sci. Lett. 83, 80-84. 

Oxygen isotope zoning in garnet was documented by the early 1990s (Chamberlain and Conrad,... 

Figure 16 Oxygen isotope profiles across a garnet from Tierra del Fuego, Chile, showing general 0.5%c increase in from core to rim. This zoning is...

Figure 32 P-T diagram showing important reactions, isopleths of oxygen isotope compositions (thin vertical lines), and inferred P-T path, as deduced from the major element, trace element, and oxygen isotope zoning in garnet porphyroblasts. The parallelogram at the end of the P-T path is the thermobarometrically derived estimate of...

Chamberlain C. P. and Conrad M. E. (1991) Oxygen isotope zoning in garnet. Science 254, 403-406. 

Crowe D. E., Riciputi L. R., Bezenek S., and Ignatiev A. (2001) Oxygen isotope and trace element zoning in hydrothermal garnets windows into large-scale fluid-flow behavior. Geology 29, 479-482. 

Kohn M. J., Valley J. W., Elsenheimer D., and Spicuzza M. J. (1993) Oxygen isotope zoning in garnet and staurolite ... 

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