Oxygen isotope fractionation in wolframite
European Journal of Mineralogy Volume 4 Number 6 (1992), p. 1331 - 1336
published: Dec 15, 1992
manuscript accepted: Feb 13, 1992
manuscript received: Apr 23, 1991
ArtNo. ESP147050406012, Price: 29.00 €
Abstract Thermodynamic oxygen isotope factors for wolframite are calculated using the modified increment method and assuming a predominant contribution of the 180-increment in complex anion to the I-18O index of complex mineral. The oxygen isotope fractionation factors obtained between quartz, wolframite and water are: 103In αquartz-wolframite= 0 . 3 8 X 106/T2 + 4.76 X 103 /T - 2.48 103In (αwolframite-water = 3.86 x106/T2 - 8.54 x 103/T + 1.44 for the temperature range from 0 to 1200°C. No difference in fractionation between ferberite and huebnerite is observed, indicating that the substitution of Fe for Mn does not significantly affect the 18O/16O partitioning in the wolframite series. When the present calibration for the quartz-wolframite system is applied to isotopic geothermometry in hydrothermal tungsten mineralizations, the temperatures calculated are well comparable to results from other geothermometric methods.