How impertinent to suggest the crater is anything other than impact-formed. But thanks for doing so. No doubt you will get blasted, but what the hey? ;-) A hot spring or some such makes eminent sense. But how to explain the break up of the rock around the rim?

Meanwhile, I have yet to see any layering in the spheroids. I've seen remarkable cleavage patterns: either in half or in quarters. Explain that if you can. And of course doubled spheres. There may be some cases of tripled spheres as well -- is this a result of the string of beads effect?

The spheres cloven neatly in twain seem completely homogeneous all the way through. At least to my unpracticed eye. Why are they breaking so cleanly? And why do we see quarter spheres, also with no apparent layering?

While I haven't seen layers (which doesn't mean they aren't there), I have seen some half-spheres lying on the ground that appear to have a rim around their flat edge. They somewhat resemble tektites -- which takes us into another realm altogether.

The abundance of sulfur in the light colored matrix is interesting.

Are these spheres forms of iron pyrite?

Cheers, BRFelix