Spinel chemistry as an indicator of crystal franctionation and liquid immiscibility in the Tapira alkaline-carbonatite complex, Minas Gerais, Brazil - Brod, J.A.; Gaspar, J.C.; Diniz-Pinto, H.S.; Junqueira-Brod, T.C. (International Kimberlite Conference: Extended Abstracts, 2003)