1. Department of Analytical Chemistry, Faculty of Science and Technology; University of the Basque Country (UPV/EHU); Barrio Sarriena s/n 48940 Leioa Spain
2. Department of Mineralogy and Petrology, Faculty of Science and Technology; University of the Basque Country (UPV/EHU); Barrio Sarriena s/n 48940 Leioa Spain
3. Department of Stratigraphy and Palaeontology, Faculty of Science and Technology; University of the Basque Country (UPV/EHU); Barrio Sarriena s/n 48940 Leioa Spain