Tourmaline records the hydrothermal events related to Zn-Pb mineralization around the Murguía diapir (Basque Cantabrian Basin, N Spain)


  • R. Galdos Faculty of Sciences and engineering, Pontificia Universidad Católica del Perú Av. Universitaria 1801, San Miguel, Lima 15088, Perú
  • A. Canals Departament de Mineralogia, Petrologia i Geologia aplicada, Universitat de Barcelona C/ Martí i Franquès, s/n, 08028 Barcelona, Spain
  • E. Cardellach Departament de Geologia, Universitat autònoma de Barcelona Edifici Cs, 08193 Cerdanyola del Vallès, Spain
  • J. Perona Centres Científics i Tecnològics, Universitat de Barcelona C/ Lluis Solé i Sabarís, 1-3, 08028 Barcelona, Spain


Tourmaline, Salt diapir, Zn-Pb deposits, Basque Cantabrian Basin


The chemical composition of tourmaline has been used as a host environment register as well as a potential exploration tool for mineral deposits. In this study, the textural and chemical composition of tourmalines associated with Zn-Pb mineralizations around the Murguía diapir (Basque Cantabrian Basin, N Spain) are examined to verify if they record the mineralizing events in the area. Petrographically, tourmalines have been differentiated between inherited and authigenic. Colorless authigenic tourmalines are present as halos partially around green and pleochroic detrital grains or as individual crystals. Inherited and authigenic tourmalines are also chemically distinct. Authigenic tourmalines show different X-site occupancies, a Mg/(Mg+Fe) ratio above 0.77, and are aluminum rich and plot to the right of the povondraite-oxidravite join, above the schorl-dravite join. Inherited tourmalines plot within the alkaline (Na+K) group field, and have a Mg/(Mg+Fe) ratio below 0.77. These data suggest that authigenic tourmalines grew under reducing conditions, compatible with the hydrothermal event responsible for the ore deposition and caprock formation during the diapir ascent.