Hot Spew
A small, continuous geyser with a heart-shaped vent, and an algal skirt of the most unfashionable shade of green, blasts boiling water and steam skyward, sounding a constant whistle reminiscent of a large tea kettle with crusty crystals clogging the spout. The mineral deposits in that case are the same basic composition as this: calcium carbonate, reconstituted from solution by rapid cooling of water. The tone and texture of the scene could be a rear-facing window into Archean times, or across space-time to another spot on another planet around another sun.
Yellowstone National Park WY (15 Sep 13) Looking NNW
44.7285, -110.7