Bosost is a well-known Zn-Pb province containing several tens of small to medium-sized deposits, distributed in a radius of about 15 km around the town of Bosost, NE Spain, where ore was processed. The Pyrenean axial uplift contains a WNW-ESE chain of domes exposing Neoproterozoic and Palaeozoic basement.
The Bosost (structural) Dome is one of these which straddles the Franco-Spanish border in the region of the central Pyrenees. It has a core of gneiss-to-migmatite produced by partial granitisation of lower Ordovician clastic sediments, in turn enveloped by an increasingly less metamorphosed mantle of lower Ordovician-to-Devonian, schist, meta-carbonates, phyllite, black slate, and shale. Thin foliation-parallel masses and stringers of sphalerite and galena locally contain copper-rich chalcopyrite-pyrrhotite intervals in a host of Ca-Mg silicate and marble-rich units infolded with meta-pelitic schist.
The Bosost orebodies are interpreted to be Palaeozoic, stratabound, syn-diagenetic (sedex?), Zn-Pb and copper sulphide accumulations, deformed and metamorphosed during the Variscan Orogeny (i.e. mainly in the Carboniferous). An alternative interpretation is that they are synorogenic replacements. Total production has probably been less than 100,000 t Zn+Pb. Source:
(Source: Peter Laznicka, 2003)