gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1998.62A.2.226 Trace Element Partitioning Between Coexisting Biotite and Muscovite of Portuguese Granitic Differentiation Series Neiva A. M. R. Silva M. M. V. G. Department of Earth Sciences, University of Coimbra, 3000 Coimbra, Portugal Gomes M. E. P. Department of Geology, University of Trás-os-Montes e Alto-Douro, 5000 Vila Real, Portugal Campos T. F. C. Department of Geology, Federal University of Rio Grande do Norte, Natal-RN CEP 59072-970, Brazil 1998 62A 2 1069 1070 Copyright © 1998, The Mineralogical Society 1998