ARTICLE Genetic constraints from paleomagnetic dating for the Aliva zinc–lead deposit, Picos de Europa Unit, northern Spain David T. A. Symons & Fernando Tornos & Kazuo Kawasaki & Francisco Velasco & Idoia Rosales Received: 9 July 2014 /Accepted: 19 February 2015 # Springer-Verlag Berlin Heidelberg 2015 Abstract Aliva has been the most productive Zn–Pb mine in the Picos de Europa Mississippi Valley-type (MVT) district of Spain’ s Cantabrian Zone. The mineralisation is hosted in a Variscan thrust sheet by strata of the Late Carboniferous (~309±3 Ma) Picos de Europa limestone–shale formation. Paleomagnetic and rock magnetic analyses of 194 specimens from 23 sites show that the sphalerite–galena–dolomite ore carries a stable characteristic remanent magnetisation (ChRM) in magnetite–titanomagnetite with minor pyrrhotite. Uncorrected for bedding tilt, the ChRM’ s direction is declina- tion (D)=347.2°, inclination (I)=61.8° (N =20 sites, k =75.4, α 95 =4.3°). A negative paleomagnetic fold test shows that the MVT mineralisation is in one or more carbonate olistoliths of the Picos de Europa Formation in shales of the overlying Late Carboniferous Lebeña Formation and that the ChRM entirely postdates Variscan orogenic deformation. No plausible tilt correction of the ChRM’ s paleopole supports a previously proposed late Variscan (Permian–Triassic) age for the genesis of the MVT mineralisation at Aliva. The paleopole does sup- port an age of 112±8 Ma for the hydrothermal dolomitisation and MVT mineralisation event with a subsequent increase in bedding tilt by ~10° NNE during the Oligocene–Miocene Pyrenean (Alpine) Orogeny. The 112±8 Ma Aptian–Albian age ties ore genesis to the 35°±2 counterclockwise rotation of the Iberian peninsula relative to stable Europe and strongly favours an origin in the rift’ s flank associated with rift hydro- thermal activity. Key words Paleomagnetism . Mississippi Valley-type ore . Picos de Europa district . Spain . Ore genesis . Aptian–Albian Introduction Aliva has been the most important zinc–lead (Zn–Pb) mine in the historic Picos de Europa Mississippi Valley-type (MVT) ore district of northern Spain (Fig. 1). This mine produced ~6×10 5 t of ore grading ~13 % Zn and ~2 % Pb from the late 1800s to 1989. The epigenetic MVT ore is related to several stratabound and discordant zones of hydrothermal dolomitisation in the Carboniferous carbonate basement rocks of the Picos de Europa Unit. None of the Picos de Europa MVT deposits have been dated either radiometrically or pa- leomagnetically. Based on geologic arguments, Gómez- Fernández et al. (2000) favoured a Permian age for the de- posits’ genesis but conceded that they could be as young as Miocene. Editorial handling: G. Beaudoin and R.L. Romer Electronic supplementary material The online version of this article (doi:10.1007/s00126-015-0579-y) contains supplementary material, which is available to authorized users. D. T. A. Symons (*) Department of Earth and Environmental Sciences, University of Windsor, Windsor, ON N9B3P4, Canada e-mail: dsymons@uwindsor.ca F. Tornos Centro de Astrobiologia, CSIC-INTA, Crta. Ajalvir Km. 4, 28850, Torrejon de Ardoz Madrid, Spain K. Kawasaki Section of Earth and Environmental Systems, University of Toyama, 3190 Gofuku, Toyama-shi, Toyama 930-8555, Japan F. Velasco Department de Mineralogia y Petrologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Spain I. Rosales Instituto Geológico y Minero de España, Rio Rosas 23, 28003 Madrid, Spain Miner Deposita DOI 10.1007/s00126-015-0579-y