Regional variations within the parana flood basalts (southern brazil): evidence for subcontinental mantle heterogeneity and crustal contamination - Piccirillo, Enzo Michele; Civetta, Lucia; Petrini, Riccardo; Longinelli, A; Bellieni, Giuliano; Comin-Chiaramonti, P.; Marques, Leila Soares; Melfi, Adolpho José (Chemical Geology, 1989)