1. Instituto Dom Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisboa 1749-016, Portugal
2. Departamento de Geologia, Faculdade de Ciências, Universidade de Lisboa, C6, Campo Grande, Lisboa 1749-016, Portugal
3. Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, Clermont-Ferrand F-63000, France
4. School of Earth and Environmental Sciences, University of Portsmouth, Building Burnaby Road, Portsmouth P01 3QL, UK