Abstract
In the southern Damara Orogen a distinct stratigraphic unit of muscovite + quartz-bearing metapelite is cut discordantly. by isograds forming garnet, staurolite, kyanite, and cordierite. The area investigated is characterized by a rather flat temperature gradient and the isograds are spaced over large distances. This gave the opportunity to study in detail the mineralogical changes in an isochemical rock series. In the present paper the formation of the various Fe-Mg-silicates is shown in relation to the variability of the whole-rock chemistry and grades of metamorphism. Furthermore, the subtle changes in mineral composition are shown as functions of the modal changes in the course of the isograd reactions. The changes of the phase relations at the various isograds are graphically analyzed by way of AFM-diagrams. In conclusion, pressure-temperature conditions of metamorphism are estimated.
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© 1983 Springer-Verlag Berlin Heidelberg
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Hoffer, E. (1983). Compositional Variations of Minerals in Metapelites Involved in Low- to Medium Grade Isograd Reactions in the Southern Damara Orogen, Namibia, South West Africa. In: Martin, H., Eder, F.W. (eds) Intracontinental Fold Belts. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-69124-9_30
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DOI: https://doi.org/10.1007/978-3-642-69124-9_30
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