|Helictites are an eccentric or "vermiform" form of stalactite
that twists and turns rather than growing straight up and down. They typically
begin as tubular lava stalactites, but
crystallization of the emerging lava as it cools pushes the lava in different
directions. Often groups of these helictites will bend in the same direction
down the passage, suggesting an influence of wind moving through the tube.
Helictites rarely have drip stalagmites lying underneath. Most likely, the crystallization at the ends of the tubes that redirect the flow also reduce it to the point that little material is ejected to fall on the floor beneath.
The top photo shows a classic group of helictites with some calcite or gypsum crust on them. In the second photo, some unusually long (over a foot) helictites formed on the end of some tubular lava statlactites. In the bottom photo, one can see just how densely these formations may cover the ceiling of a tube. Needless to say, these formations are extremely delicate and caution must be taken when exploring near them.
|Created: August 4, 2000
Author: Dave Bunnell