?ALBERTI, A., CASTORINA, F., CENSI, P., COMIN-CHIARAMONTI, P. and GOMES, C.B. 2000. Geochemical characteristics of Cretaceous carbonatites from Angola. Journal of African Earth Sciences, 29: (in press).ALLSOPP, H.L. and HARGRAVES, R.B. 1985. Rb-Sr ages and?. 2000.