Yeah, that's from a crater. I saw it in one of those science shows that I'm always watching on the Science Channel...I think was called "How the earth was made" and it was in one of the episodes. Might be a different tv series, I can't keep them all straight in my head. Normally you'd think that the crater edges would prevent a ring river but the mound-in-the-middle resulting from the impact was very dense so it eroded very slowly while the edges were closer to normal dirt so they eroded faster. There's a few others like this in Asia and Central America if I remember right.