Partition of trace elements in co-existing biotite, muscovite and potassium feldspar of granitic rocks, northern Portugal

Geochemistry of Coexisting Biotite and Muscovite of Portuguese Peraluminous Granitic Differentiation Series

“…Partition ratio for Cr in series 4 is higher by two orders of magnitude than in series 2 (Table 10), but similar to that found by Neves (1997). In biotite/muscovite pairs commonly Cr and V prefer biotite (Albuquerque 1975;Neiva 1977;Neves 1997).…”

“…Rare data were found in the literature on Nb and Zn of coexisting biotite and muscovite from granitic rocks, but they prefer biotite rather than coexisting muscovite (Jolliff et al 1992;Neves 1977) as in this study. Li is more concentrated in biotite than in coexisting muscovite (Tables 4 to 9) as found by Carron and Lagache (1972), Albuquerque (1975), Kretz et al (1989), Jolliff et al (1992), Bea et al (1994) and Neves (1997).…”

“…Partition ratios could only be calculated for Cr of series 2 (Jales) and series 4 (Torrão) and for Cs of series 6 (Serra da Estrela), because only for them regression lines pass through the origin. Most trace elements have a higher concentration in biotite than in coexisting muscovite (Tables 4, 5, 6, 7, 8 and 9), but Sn, Sc and Ba show preference for muscovite (e.g., Albuquerque 1975), which cannot be the result of late muscovite crystallization from an enriched residual melt, because this melt would have been impoverished in Sc and Ba as shown by the decrease in Ba content in biotite from Serra da Estrela series ( Fig. 4) and muscovite from Jales series (Fig.…”

“…Micas are important in the evolution of peraluminous granitic series. Major and trace elements of micas give good information during the evolution of granitic magmas (e.g., Neiva 1973Neiva , 1977Neiva , 1993Neiva , 1998Albuquerque 1975;Neiva and Gomes 1991;Neiva et al 1987;Hall et al 1993;Silva andNeiva 1990, 2000;Tischendorf et al 2001). The crystal chemistry of coexisting biotite and muscovite from peraluminous granites seems to be a good indicator of chemical events during crystallization, as shown by Brigatti et al (2000).…”

“…Experimental data of trace element partitioning among biotite, muscovite and peraluminous silicic melt are scarce (Icenhower and London 1995). Calculated distribution coefficients for biotite-muscovite pairs are scarce, because equilibrium must be found (e.g., Albuquerque 1975, Bea et al 1994. They must be compared with those derived from crystal melt distribution coefficients.…”