Contents lists available at ScienceDirect Geochemistry journal homepage: www.elsevier.com/locate/chemer Geochemistry of granitic aplite-pegmatite dykes and sills and their minerals from the Gravanho-Gouveia area in Central Portugal Ana Margarida Ribeiro Neiva a,b, ⁎ , Carlos Leal Gomes c , Paulo Bravo Silva d , Maria Elisa Preto Gomes e , António Carlos Tavares dos Santos a,b a GeoBioTec, Department of Geosciences, University of Aveiro, 3810-193 Aveiro, Portugal b Department of Earth Sciences, University of Coimbra, 3030-790, Coimbra, Portugal c Department of Earth Sciences, University of Minho, Gualtar, 4710-057, Braga, Portugal d União Temporária de Empresas IGME-LNEG-IIA, 4466-956 S. Mamede de Infesta, Portugal e CEMMPRE, Department of Geology, University of Trás-os-Montes e Alto Douro, 5000-911, Vila Real, Portugal ARTICLE INFO Keywords: Variscan granites Pegmatites Feldspars Micas Fractionation series Cassiterite Hydrothermal fluids ABSTRACT Two distinct series of Variscan granitic rocks have been distinguished in the Gravanho-Gouveia area of Portugal, based on field work, variation diagrams for major and trace elements, rare earth patterns and δ 18 O versus total FeO diagram of rocks, anorthite content of plagioclase, BaO and P 2 O 5 contents of feldspars and Al VI versus Fe 2+ diagram for magmatic muscovite. One series consists of a late-orogenic porphyritic biotite > muscovite granite (G1), less evolved beryl-columbite pegmatites and more evolved beryl-columbite pegmatites showing grada- tional contacts. The other series consists of post-orogenic porphyritic muscovite > biotite granodiorite to granite (G2), slightly porphyritic muscovite > biotite granite (G3) and lepidolite pegmatites. In each series, pegmatites are derived from the parent granite magma by fractional crystallization of quartz, plagioclase, K- feldspar, biotite and ilmenite. Some metasomatic effects occur like muscovite replacing feldspars, chlorite in pegmatites of the first series and a late muscovite in pegmatites of the second series, probably due to hydro- thermal fluids. The lepidolite pegmatites contain cassiterite and two generations of rutile. The first magmatic generation consists of homogeneous crystals and the second generation occurs as heterogeneous zoned crystals derived from hydrothermal fluids. The beryl-columbite pegmatites and lepidolite pegmatites also contain the first magmatic generation and the late hydrothermal generation of zoned columbite-group minerals. More evolved beryl-columbite pegmatites were converted into episyenite by intense hydrothermal alteration and regional circulation of fluids in the granitic rocks. 1. Introduction Granitic pegmatites, their inner-zonings and minerals have been studied by several authors (e.g., Černý et al., 1985a, b, 2005; London, 2008; London and Morgan, 2012; Neiva, 2013; Neiva and Ramos, 2010; Roda-Robles et al., 2012, 2016). The origin of granitic pegma- tites is mainly attributed to the differentiation of a granite magma. However, a few other authors have contested that origin for LCT pegmatites (Černý and Ercit, 2005) and suggest that they result from anatexis (e.g., Stewart, 1978; Bongiolio et al., 2016; Simons et al., 2016). Granitic aplite-pegmatites and their minerals from three areas of central Portugal, in the Central Iberian Zone, have been studied and result from fractional crystallization of quartz, plagioclase, K-feldspar, biotite and ilmenite of a two-mica granite magma in each area, sup- ported by modelling of major and trace elements (Neiva et al., 2008, 2012; Neiva and Ramos, 2010). The fourth area chosen for study, the Gravanho-Gouveia area, is significantly different from those already studied, the Arcozelo da Serra area, Guarda-Belmonte area and Sabugal area, because pegmatites often are metasomatically altered and episyenitization occurs in the area. In general, it is difficult to obtain chemical analyses of metaso- https://doi.org/10.1016/j.geoch.2019.01.001 Received 24 May 2017; Received in revised form 5 January 2019; Accepted 10 January 2019 ⁎ Corresponding author at: GeoBioTec, Department of Geosciences, University of Aveiro, 3810-193 Aveiro, Portugal. E-mail address: neiva@dct.uc.pt (A.M.R. Neiva). Chemie der Erde xxx (xxxx) xxx–xxx 0009-2819/ © 2019 Elsevier GmbH. All rights reserved. Please cite this article as: Ana Margarida Ribeiro Neiva, et al., Chemie der Erde, https://doi.org/10.1016/j.geoch.2019.01.001