HR: 17:45h
AN: V54A-08    [Abstracts]
TI: Empirical Calibration of Vanadium Partitioning Between Magnetite and Ilmenite as an Oxybarometer
AU: * Duchesne, J
EM: jc.duchesne@ulg.ac.be
AF: Department of Geology, University of Liege, Bat. B20, Sart Tilman, 4000, Belgium
AU: Charlier, B
EM: b.charlier@ulg.ac.be
AF: Department of Geology, University of Liege, Bat. B20, Sart Tilman, 4000, Belgium
AU: Vander Auwera, J
EM: jvdauwera@ulg.ac.be
AF: Department of Geology, University of Liege, Bat. B20, Sart Tilman, 4000, Belgium
AB: Vanadium is measured in magnetite and ilmenite collected in two Fe-Ti ore deposits characterized by different fO₂. In the Grader ilmenite deposit (Havre-Saint-Pierre anorthosite complex, Quebec), the fO₂ has been estimated at ΔNNO ca. +0.6 log units, whereas in the Fedorivka layered intrusion (Korosten anorthosite, Ukraine) a lower fO₂ ranges from ΔFMQ >+0.7 log units down to -1.4 log units. After correction for subsolidus compositional re-equilibration of the magnetite, the partition coefficient of vanadium between magnetite and ilmenite D is compared to the (Eu²⁺/Eu³⁺)_plag ratio calculated from the Eu distribution between pairs of plagioclase and apatite. Both parameters show good correlation, (Eu²⁺/Eu³⁺)_plag varying from ca. 30 to ca. 200, and D from ca. 1 to 27. Calibrations of the two oxybarometers are proposed. Though further experiments are needed better to ascertain the relationships, comparison with independent data shows that the empirical estimates of fO₂ with D are credible.
DE: 1065 Major and trace element geochemistry
DE: 3618 Magma chamber processes (1036)
DE: 3643 Layered magma chambers
DE: 3651 Thermobarometry
DE: 8439 Physics and chemistry of magma bodies
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting