Comment on the paper of de Ignacio, C., Muñoz, M., Sagredo, J., Fernández-Santín, S. and Johansson, A., 2006. Isotope geochemistry and FOZO mantle component of the alkaline-carbonatitic association of Fuerteventura, Canary Islands, Spain. Chem. Geol. 232, 99-113