A Desert at the South Pole
The sandstone sculptures of Vila Velha State Park are remnants of a landscape different from modern Brazil. They belong to the Ponta Grossa and Furnas Formations, geological units deposited during the Devonian Period, approximately 400 million years ago. At that time, this part of South America was attached to Africa as part of the supercontinent Gondwana. The continent was positioned at a much higher latitude, placing the Paraná Basin—an intracratonic depression covering 1.5 million square kilometers—near the South Pole.
The whitish, coarse-grained sandstone of the Furnas Formation represents a coastal environment, where fluvial systems met a shallow sea. Visible within these rocks are distinct layers and patterns known as planar cross-bedding. These structures are the fossilized remains of large sand dunes, shaped by persistent winds blowing across an arid, cold desert. The layers show the direction and angle of the ancient wind, freezing a 400-million-year-old weather report in stone. The entire Paraná Group, which includes these formations, reaches a maximum thickness of 800 meters.
From Sea Floor to Sculpted Towers
Above the desert sands, the geological story shifts. A global rise in sea level is recorded by the transition to the dark, fine-grained shales of the Ponta Grossa Formation. This unit was deposited in a shallow marine environment that flooded the earlier desert. These marine rocks contain a collection of Devonian fossils known as the Malvinokaffric fauna. This fossil assemblage includes trilobites, brachiopods, gastropods, and Tentaculitoidea, which are small, conical shelled invertebrates. These creatures thrived in the cold, high-latitude waters that covered the region.
The striking shapes seen today—resembling a goblet or a camel—are not from the Devonian; are the product of millions of years of erosion. After the layers of sand and mud lithified into rock and were uplifted, wind and water began to exploit weaknesses. The sandstone is cemented by materials of varying hardness. Softer sections wear away more quickly, a process called differential erosion, leaving behind the more resistant portions as free-standing sculptures. The entire park covers 3,803 hectares, preserving these geological monuments.