Mysterious island in Argentina

[Pollux]

Here's a video that is (theoretically) showing other such lakes. Maybe it's not as much of a one-off as thought.

I'm puzzled. Does this video of yours add to something, about this phenomenon ,here that we didn't know before?

Interesting article:

https://www.gearthblog.com/blog/archives...ntina.html

Thanks for this. Obviously I was wrong to judge by appearances and to think this couldn't be a natural formation. 

However, I'm still not convinced it has much to do with ice circles, except in the most general terms. I think the other examples, including those in berkelon's video, argue against the idea that the floating islands are "carving out" a circular hole as that blog post suggests. It looks more to me as though the lakes that are circular, are circular because they're sinkholes, as Pollux suggested. Most of the islands are smaller than their lakes, though there's another example near the end of the video where the island fills nearly the whole lake. I suppose sinkholes are conducive towards floating islands because they don't have shallows near their edges, so the islands don't tend to run aground and become attached to the shore.

I'm puzzled. Does this video of yours add to something, about this phenomenon ,here that we didn't know before?

That it isn't a one-off. That it is something that happens naturally. I imagine one of the things that intrigues people the most about things like this is the "perfect", uniform shape of the island and surrounding lake in the OP, and the notion that it is a "one of a kind" thing. You see this quite a bit with the "it must be aliens" crowd. They'll point to the "perfect circles" and say that they couldn't be natural or even human-made. In fact, I think the guy in the OP video said something similar (about how perfect the circles were, and how intriguing that was, not that it was aliens). But when you see other examples of basic setup in different places, in irregular shapes, it helps you to realize that it is probably just floating vegetation that occurs with some frequency. That's what I took away from it. If it's a somewhat common thing that looks more and more like floating vegetation, why be so baffled by it, and why have a kickstarter? I'm puzzled that you didn't gleam that from the video I posted...