U-Pb dating of stockwork zircons from the eastern Iberian Pyrite Belt

Zircons found in the stockwork zones of the massive sulphide Los Frailes deposit, Iberian Pyrite Belt, are interpreted to have grown during the hydro thermal alteration of host felsic volcanic rocks. Ion microprobe (SHRIMP) dating gives a 206Pb/238U age of 345.7 [+ or -] 4.6 Ma (2[Sigma]) and together with published spore data from the deposit suggest an age of uppermost Devonian to lowermost Carboniferous. Stockwork zircons offer the possibility of precisely defining the emplacement ages of these giant sulphide accumulations over the whole Pyrite Belt and from this will emerge estimates of the thermal budget necessary to generate the deposits. Keywords: Iberian Pyrite Belt, Devonian, SHRIMP, hydrothermal processes, zircons.