rio's rocky and granite formations trace their beginning to the  paleozoic era, when ancient continents very slowly conglomerated to form a massive body of land called 'gondwana'. rio's mountain ridges, on the other hand, formed much later, with the fracturing of the supercontinent gondwana and the drifting of the continents.

during the formation of gondwana the heat caused by the collisions was so high to melt some of the pre-existing rocks, creating large quantities of magma, or molten rocks, deep below the surface.once cooled, the magma remained in the shape of the rocky and granite hills typical for rio such as the sugar loaf, the morro da urca, and the ilha redonda part of the cagarras islands.