Vista Alegre
Key facts
- Country
- Brazil
- Diameter
- 9.5 km
- Age
- about 111 to 134 million years
- Location
- 25.95° S, 52.68° W
A round depression about 9.5 km across in the farmland of south-western Paraná, Brazil, near the town of Coronel Vivida.
Vista Alegre is an impact structure about 9.5 km across in the state of Paraná, southern Brazil. Like its neighbour Vargeão Dome, about 100 km to the south, it formed in basalt lava, a rare kind of target on Earth.
What it hit. The impactor struck the Serra Geral basalts, a vast pile of lava flows that covered southern Brazil around 134 million years ago, along with sandstones beneath them. The crater has a raised rim and a central area of broken rock.
Proof of impact. The round structure was noticed on satellite images. In the early 2000s geologists found impact breccias, including breccia containing fragments of melted rock, together with shatter cones and quartz grains with shock features. These confirmed an impact, and the results were published in 2004.
Age. The impact must be younger than the basalts, about 134 million years old. Dating of the impact rocks points to an age of roughly 111 million years, but estimates vary.
Why it matters. Vista Alegre and Vargeão together give geologists two rare examples of impact craters in basalt, the type of rock that covers large areas of the Moon, Mars and Mercury. The impactor is unknown.
Did you know?
Vista Alegre formed in basalt lava, like many craters on the Moon.
Its impact origin was confirmed in 2004.
It lies about 100 km from another basalt crater, Vargeão Dome.