Cerro do Jarau, a Probable Impact Crater

About this place

Cerro do Jarau is a striking circular landform in Quaraí, in western Rio Grande do Sul near the border with Uruguay. About thirteen and a half kilometres across, it rises more than two hundred metres above the flat pampas and from afar looks like an arc of hills. Its origin puzzled scientists for decades: was it formed by forces from within the Earth or by the impact of a huge meteorite? Recent studies found features in its rocks that are thought to form only under the extreme pressure and heat of a collision with a body from space, and its age is put at about 117 million years. The Russian Academy of Sciences lists it as a probable impact crater. What is seen today is not the crater itself but its rim, which rose like a wave around the point of impact and was then worn down by wind and rain. The hills also hold a place in southern folklore as the setting of the legend of the «Salamanca do Jarau», recorded by the writer João Simões Lopes Neto, and served as a lookout during the nineteenth-century Farroupilha Revolution. The land around is private ranchland, so the hills are seen from the road and climbing needs local permission.