I was just playing around with Google maps and I stumbled across this lake in eastern Canada, and thought it looked rather weird.
I'm not a geologist so I am not sure what the heck is going on here. Trying to guess how this formed my first thought was volcanic crater filled with water and central island pushed up by magma pressure. But usually the island in a volcanic lake is much smaller than the lake, this looks more like a circular river. The overall size isn't typical. The ring lake is 35 miles across and the island is about 25 miles diam. So if this is volcanic it is not a normal size volcano, it would have to be a Super Caldera.

Any one more knowledgeable care to comment?

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