oa Lithospheric Structure Beneath The Parana-Etendeka Province

The Paraná-Etendeka province comprises one of the largest continental flood basalt provinces on earth. This magmatic province was associated with the opening of the South Atlantic Ocean during the Early Cretaceous. The Paraná lava field covers an area of at least 1.2x106 km2 over southern Brazil, Uruguay, eastern Paraguay and northern Argentina, and its present extent is bounded by the margin of the underlying Palaeozoic-Mesozoic Paraná basin. The Etendeka lavas, are scattered over an area of 0.8x105 km2 in northwestern Namibia. The basement beneath the Paraná basin consists of several Archean to Early Proterozoic cratonic blocks surrounded by Brasiliano cycle (700-450 Ma.) mobile belts. The majority of analysed samples of the Paraná-Etendeka magmatism give 40Ar-39Ar ages between 129 Ma and 134 Ma with northward younging, although there is evidence of earlier magmatism inland (135-138 Ma) and younger magmatism persisting along the coast (120-128 Ma).