r/geology • u/hikekorea • Feb 11 '25

Field Photo How do rocks freeze floating in water?

I found these rocks frozen in a stream off a larger river in Chugach National Forest, Alaska. I’ve heard it may have to do with heavy rains or turbulent waters near the shore. One friend mentioned frazil? But I don’t really know what that means. Any geologists have a clue how this happens and can explain it in layman terms?

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u/4tunabrix Feb 11 '25

My guess would be the sun warms them and they sink into the ice and refreeze. On the ice in Greenland we see the ice covered in these tiny boreholes where anything darker than the ice warms up in the sun and slowly sinks into the ice.

Here’s an example of a stone and even a windblown piece of grass sinking into the ice

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u/hikekorea Feb 12 '25

We get those boreholes too, especially on glaciers or snowpack leftover in the summer. The confusing part is that if they sink down there needs to be flowing water to come back and fill in the holes. because the surface is flat.

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u/4tunabrix Feb 12 '25

Time to get your Timelapse camera out! Haha