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Ilmenite exsolution in olivine from the serpentinite body at Zöblitz, Saxonian Erzgebirge – microstructural evidence using EBSD

Published online by Cambridge University Press:  05 July 2018

H.-J. Massonne  and
R. D. Neuser
H.-J. Massonne*
Affiliation:
Institut für Mineralogie und Kristallchemie, Universität Stuttgart, Azenbergstr. 18, D-70174 Stuttgart, Germany
R. D. Neuser
Affiliation:
Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
*
*E-mail: [email protected]
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Abstract

In the large serpentinite body at Zöblitz, which is part of the Gneiss-Eclogite Unit of the Saxonian Erzgebirge, ilmenite rods have been detected in olivine. Although these rods are ≤1 μm wide, they can be unequivocally identified as ilmenite using electron backscatter diffraction. We also applied this method to prove that ilmenite is topotactically intergrown with the olivine host ([100]ol ‖ [001]ilm). This relation was found previously, e.g. for ilmenite exsolved from olivine of garnet peridotite from Alpe Arami, Swiss Alps. The degree of this exsolution phenomenon in the Alpe Arami rocks was taken as an indication of the original formation of a Ti-bearing mineral at depths of ∽300 km. As in the olivines of the serpentinite from Zöblitz, the density of the ilmenite rods is significantly less than in the rock from Alpe Arami. We think that our observation is compatible with previous P-T estimates of close to 4 GPa and 1000–1100°C for the ultramafic bodies in the central Saxonian Erzgebirge.

Keywords

olivineilmeniteexsolutionultrahigh pressure metamorphismgarnet peridotiteSaxonian ErzgebirgeGermanyelectron backscatter diffraction (EBSD)
Type
Research Article
Information
Mineralogical Magazine , Volume 69 , Issue 2 , April 2005 , pp. 119 - 124
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2005

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