Geology and structure of Rio Tinto Mine (Iberian Pyrite Belt, Spain)

The Rio Tinto mining district is regarded as the largest volcanogenic massive sulphide district worldwide, but its geologic and structural setting remains poorly disclosed. The mineralized sequence includes a lower unit of interbedded mafic volcanics, shale and conglomerate overlain by a felsic dome-sill complex. The massive sulphides occur within the felsic rocks, either as exhalative deposits on the top or as replacive masses within the volcaniclastic rocks. The present review has a special aim on structural geology bearing up a genetic model update for the ore. Regional thin-skinned tectonic was clearly identified as the leading Variscan structural style in the district. Several stocked units bounded by thrust-faults display normal polarity on structural and sedimentary criteria basis. Reconstruction of the palaeogeography prior to the tectonic stacking reveals a very extensive mineralizing syste