Massive sulphide deposits of the Tharsis Mining District (Iberian Pyrite Belt) are included in a black shaly series that is stratigraphically conformable with the underlying Phyllite–Quartzite Group. Well-preserved palynomorph assemblages have been obtained from this shaly series. The miospore assemblages are assigned to the LN Biozone, indicating a latest Devonian age. This is consistent with the Re–Os age of 348.6 ± 12.3 Ma from both massive sulphides and stockwork mineralization. Palynological and isotopic results from elsewhere in the Pyrite Belt are similar, suggesting that mineralization was synchronous throughout the region.