Ore Geology Reviews 134 (2021) 104147 Available online 6 April 2021 0169-1368/© 2021 Elsevier B.V. All rights reserved. U-Pb zircon SHRIMP dating of a protracted magmatic setting and its volcanic emplacement: Insights from the felsic volcanic rocks hosting the sulphide ore of the giant Aljustrel deposit, Iberian Pyrite Belt Jo˜ ao Lains Amaral a, b, c, * , Ana Rita Sol´ a c , Telmo M. Bento dos Santos a, b , Colombo C. G. Tassinari d , Jo˜ ao Gonçalves e a Departamento de Geologia, Faculdade de Ciˆ encias da Universidade de Lisboa, Ed. C6, Piso 4, Campo Grande, 1749-016 Lisboa, Portugal b Instituto Dom Luiz (IDL), Ed. C1, Piso 1, Campo Grande, 1749-016 Lisboa, Portugal c Laborat´ orio Nacional de Energia e Geologia (LNEG), Bairro do Zambujal, Apartado 7586-Alfragide, 2610-999 Amadora, Portugal d Instituto de Geociˆ encias e Instituto de Energia e Ambiente, Universidade de S˜ ao Paulo, Rua do Lago, 562, 05508-900 S˜ ao Paulo, SP, Brazil e Almina – Minas do Alentejo, S.A., Algares 7600-015, Aljustrel, Portugal A R T I C L E INFO Keywords: Iberian Pyrite Belt VHMS deposits Zircon U–Pb geochronology Felsic volcanic rocks Prolonged magmatic activity ABSTRACT A geochronological study using SHRIMP U-Pb analysis of zircon grains has been conducted to date felsic volcanic rocks hosting the six massive sulphide deposits of the giant Aljustrel mining district in the Iberian Pyrite Belt. A multiple method age calculation approach was used to validate and ponder calculated Concordia ages (emplacement and inherited), which included weighted average, probability density peak(s), Tuff Zirc and Unmix functions. This approach was particularly useful to interpret the wide continuous single U-Pb ages (320–405 Ma) recorded in the Aljustrel volcanic rocks. The volcanic pile (>250 m) that hosts the Aljustrel deposits was emplaced between 359 and 353 Ma. Upper Devonian inheritance, representing subvolcanic activity, is well-represented in the volcanic rocks of Aljustrel (373–365 Ma). Older Devonian inherited zircon ages at 405 Ma, 388 Ma and 380 Ma were retrieved, hypo- thetically representing deep plutonism or other melting episodes, which suggests a long-lasting (~50 Ma) magmatic activity in the Aljustrel district. Older pre-Devonian inherited ages, uppermost Silurian and early to late Cambrian, and post-emplacement ages (~330–345 Ma) were also detected, with the latter refecting Pb loss most likely driven by the main Variscan orogenic event. Maximum ages obtained for the volcanic rocks in the different deposits open the possibility that the last pulses of volcanic activity and subsequent deposition of the massive sulphides were diachronic in the different Aljustrel sub-basins. Additionally, results imply that, contrary to previously assumed, Gavi˜ ao and S˜ ao Jo˜ ao-Moinho de- posits are probably not the same ore lens disrupted by tardi-Variscan faults. This opens new opportunities for mining exploration and targeting in the Aljustrel district and points out the importance of high-resolution geochronological studies in mining and brownfeld areas. 1. Introduction Volcanogenic massive sulphides (VMS) are important polymetallic commodities representing ~20% of the worldwide Cu + Zn + Pb min- eral resources, with an estimated global tonnage of 4245.7 Mt averaging 4.17% (Mudd et al., 2017). In the Iberian Pyrite Belt (IPB), the current 7 mine operations have a total estimated resource tonnage of ~200–250 Mt; which represents ~10–15% of the overall ore identifed and exploited in this belt (Leistel et al., 1997). The IPB has been characterized as a world-class volcanogenic massive sulphide (VMS) or volcanic-hosted massive sulphide (VHMS) belt (Relvas et al., 2001; Tornos, 2006). VHMS ore deposits are often generated in a subaqueous rift-related environment, in which sulphides precipitate from hydrothermal fuids forming stratiform ores (and feeder ores) at seafoor or just below it, commonly hosted by felsic or bimodal volcanic-rich successions. VHMS deposits can also be found associated to detrital-rich successions in which direct evidences of volcanism may only be found in distal volcanogenic/tuffaceous layers (Hart et al., 2004; * Corresponding author. E-mail address: joao.lains.amaral@gmail.com (J. Lains Amaral). Contents lists available at ScienceDirect Ore Geology Reviews journal homepage: www.elsevier.com/locate/oregeorev https://doi.org/10.1016/j.oregeorev.2021.104147 Received 22 December 2020; Received in revised form 16 March 2021; Accepted 28 March 2021