The Araguainha impact: a South American Permo–Triassic catastrophic event

The Araguainha meteorite impact was certainly one of the most catastrophic events in the history of the South American continent. The impact occurred around 250 Ma ago, when the region was covered by the estuarine waters of the Parana Basin in central parts of Brazil. The impacting body of approximately 2–3 km in diameter was sufficiently large to excavate a 2 km-thick sedimentary sequence of the Parana Basin and to expose a 4 km-wide core of basement crystalline rocks in the central part of the crater. The huge scar left by the meteorite collision is 40 km in diameter, the largest and best preserved impact crater on the continent. Combined field observations and remote sensing analysis demonstrates that the Araguainha impact structure preserves all morphological/structural features of large lunar craters, being thus an important analogue to study large extraterrestrial craters. The catastrophic energy released upon impact, close to 10⁶ megatons of TNT, must have been disastrous for marine organisms living in the Parana Basin. Ongoing studies are currently evaluating the link between the Araguainha impact and the Permian–Triassic mass extinction, which is the greatest of the mass extinctions in Earth history.