How did the Serra Geral basalts form a plateau in Brazil?

The Serra Geral basalts formed a plateau in Brazil through extensive volcanic activity approximately 135 million years ago. This process occurred as flood basalts—voluminous, fluid lava flows—buried the preexisting terrain.12

These eruptions took place before the separation of South America and Africa, when the region was positioned over a hot spot that now underlies the volcanic island of Tristan da Cunha in the South Atlantic Ocean. Because the lava was erupted in such large volumes and carried long distances from its sources, the resulting topography is not dominated by individual volcanic centers but rather by a broad, flat-topped surface. Today, this solidified lava rock, often referred to as diabase, forms the Paraná Plateau, which is part of the Brazilian Highlands. While the surface is generally flat, it has been dissected over time by rivers, creating features such as the Iguaçu Falls, where water flows over the resistant rock rim.1234