“Waves,” or crenulations, occur not only on water icicles, but also in caves on dripstone and flowstone speleothems composed of calcite, epsomite, goethite, and even mud. All of these formations display “wavelengths” of around 1 centimeter. The origin of these crenulations is due not to heat, but to greater evaporation and carbon dioxide loss from thin liquid-water films flowing over slight surface protrusions.

Carol A. Hill
Albuquerque, N.M.

From the Nature Index

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