Taberlet and Plihon describe the fascinating phenomenon of “Zen stones”, which
are natural structures in which a stone, initially resting on an ice surface, ends up balanced atop a narrow ice pedestal.
They claim that they
have demonstrated that the formation is driven by differential sublimation of the ice, caused by the shade in the IR spectrum provided by the stones
and that they
have shown that the dip surrounding the pedestal is caused by the FIR emitted by the stone itself, which enhance the overall sublimation rate in its vicinity.
An article in Physics World described Tsai and Wettlaufer’s conclusions in more approachable language: Icy stars reveal the secret of their patterns.
In short, they posited a mathematical model to explain how:
radial fingers of (relatively warm) water-rich regions grow from a central source and evolve through a competition between thermal and porous media flow effects in a saturated snow layer covering the lake.
Bob Dill referred to these formations also as “ice stars” and (my personal favorite) “ice octopi”. His ice stars page on Lake Ice described a number of factors that go into their formation, and his ice octopus pictures page collected a range of photos of the phenomenon.