Most anyone that's ever heard of caves knows what stalactites are, even if they can't keep them straight from stalagmites. (Some useful associations are that stalactites hang "tite" while stalagmites hold "mite", or that stalactites are on the ceiling, stalagmites on the ground.) The following photos, however, show something that most people probably haven't thought about: the birth of stalactites. Actually it's more a coming of age, the natural evolution of a special type of stalactite: the soda straw.
Crystals of calcite in a soda straw are oriented longitudinally and grow downward, so lengthening the straw. Most soda straws, however, eventually conduct water along their external surface, as well, and there deposit radially oriented calcite crystals perpendicular to their outer surface. This leads to thickening of the soda straw into the classical "icicle" shape most people associate with stalactites. Internal flow may continue, but often ceases as external growth envelopes the former drip canal. The photos below illustrate this critical "adolescent" stage in the development of stalactites.
|Created: June 19, 1995
Last Updated: October 19, 1995
Author: Djuna Bewley