HR: 18:05h
AN: V44A-08    [Abstracts]
TI: Textural relationship and compositions of ilmenite-corundum exsolutions in rutile from kimberlitic kyanite eclogite xenoliths: microstructural evidence using EBSD
AU: * Sobolev, N V
EM: sobolev@uiggm.nsc.ru
AF: Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3 Koptyug Ave., Novosibirsk, 630090, Russian Federation
AU: Schertl, H
AF: Institute of Geology, Mineralogy and Geophysics, Ruhr University Bochum, Bochum, D- 44780, Germany
AU: Neuser, R D
AF: Institute of Geology, Mineralogy and Geophysics, Ruhr University Bochum, Bochum, D- 44780, Germany
AU: Lavrentiev, Y G
AF: Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3 Koptyug Ave., Novosibirsk, 630090, Russian Federation
AU: Logvinova, A M
AF: Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3 Koptyug Ave., Novosibirsk, 630090, Russian Federation
AU: Usova, L V
AF: Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3 Koptyug Ave., Novosibirsk, 630090, Russian Federation
AB: Rutile is one of the most common accessory minerals in high pressure (HP) and ultrahigh-pressure (UHP) rocks of crustal and mantle origin. Among those rocks eclogites are very abundant in metamorphic belts and as xenoliths in kimberlite pipes. Some of these xenoliths contain coesite or diamond. Eclogite xenolith rutiles contain high abundance of minor elements reaching up to 0.8 wt.% Al₂O₃, 2.5 wt.% Fe₂O₃, 1.4 wt.% Nb₂O₅, 0.45 wt.% ZrO₂ and are mostly heterogeneous with widely varying Al, Fe and Mg contents. These heterogeneities are caused by the presence of closely associated sigmoidal oriented lamellae of ilmenite and corundum which have been detected for the first time in rutile from Roberts Victor mine eclogite xenolith (Sobolev, Yefimova, 2000, Intern. Geol. Rev., v. 42, p. 758-767). We report here on the wide occurrence of such lamellae in rutiles both from diamondiferous kyanite eclogites of Udachnaya mine, Siberia and more samples from Roberts Victor mine confirmed by EMPA. Electron backscatter diffraction (EBSD) measurements on two rutile grains from Roberts Victor mine kyanite eclogite confirm the presence of ilmenite plus corundum exsolutions. We found evidence for respective different crystallographic orientations related to the surrounded rutile host which will be demonstrated in detail in the present study.
DE: 1042 Mineral and crystal chemistry (3620)
DE: 1065 Major and trace element geochemistry
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting