La Cuenca paranaense. Influencia de los basaltos en la interpretación gravimétrica

Abstract

The Parana basin was in the lower Cretaceous - upper Jurasic witness of non explosive lava eruptions that covered a large part of the basin in several interestratified layers. Frequently the thickness.of each layer is more than 80 m, while the sequence reach the 1 000 m near Salto (Uruguay). The maximum distance run over by the lavas from the emission center was estimated in about 100 km, consistently with the small regional tilt. We think that the exceptional expression of outpouring lavas (more important than those of India) would be a regional phenomenon integrated by many local interrelationed events. The gravimetric studies suggest the existence of subvolcanic bodies that are interpreted as old intracortlcal magma tic chambers. Different gravimetrical models were analyzed showing that intracortical positive masses associated with effusive events canjustify the observed gravity.