petrological and mineralogical evidence of the impact. Further geomorphologic evidence was published by Theilen-Willige (1981). A magnetic survey was conducted by Fischer and Masero (1994). Dome formation was first dated (at years ago, with Rb-Sr method) by Deutsch et al. (1992). Engelhardt et al. (1992) published a detailed study of the uplifted core and a revised date of about 246 million years ago, later revised to about 244 million years ago. Most recently it was dated by Tohver et al. (2012) at years ago. Effects Recent dating by Tohver et al. (2012), to years ago, places the impact at dates overlapping estimates for the Permo-Triassic boundary. and the Permian–Triassic extinction event. Much of the local rock was oil shale. The estimated energy released by the Araguainha impact is insufficient to be a direct cause of the global mass extinction, but the colossal local earth rifting would have released huge amounts of oil and gas from the shattered rock. The resulting sudden global warming might have precipitated the Permian–Triassic extinction. References External links Impact craters of Brazil Permian impact craters Permian–Triassic extinction event Landforms of Mato Grosso Landforms of Goiás Geology of Brazil First 100 IUGS Geological Heritage Sites