Suavjärvi crater

Suavjärvi (in Karelian, Russian: Суавъярви) is a lake and impact crater in the Republic of Karelia, Russia about 50 km north of the town of Medvezhyegorsk. The approximately 3 km wide Suavjärvi lake is located in the centre of the crater.

Map of Suavj%C3%A4rvi crater, Republic of Karelia, Russia, 186333

The crater is 16 km in diameter and it is estimated to be about 2.4 billion (2.4 x 10⁹) years old, placing it in the Archean–Proterozoic boundary. That makes it the oldest known impact crater on Earth. Not much of the crater has survived, although some shock features like large blocks composed of impact breccia have been found.