gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1998.62A.1.177 Achieving Geological Precision in Metamorphic Geochronology: A Th-Pb Age for the Syn-Metamorphic Formation of the Mallnitzermulde Synform, Tauern Window, from Individual Allanite Porphyroblasts Cliff R. A. School of Earth Sciences, University of Leeds, Leeds, LS2 9JT, UK Oberli F. Meier M. Inst. f. Isotopengeologie und Mineralische Rohstoffe, Departement Erdwissenschaften, ETH Zentrum, CH-8092 Zürich, Switzerland Droop G. T. R. Department of Earth Sciences, University of Manchester, OxfordRd, Manchester, M13 9PL, UK 1998 62A 1 337 338 Copyright © 1998, The Mineralogical Society 1998