Paranapanema block

The Paranapanema block is a coherent block of lithosphere located in southeastern South America spanning roughly the same area as the Paraná Basin. The existence of a tectonically stable zone beneath the Paraná Basin was first suggested in 1975. Despite difficulties in accessing the buried Paranapanema block it is inferred it must be composed mostly of orthogneiss and the it existed before the Brasiliano orogeny.