> This "ripple" pattern is observed only on icicles (and stalactites?) > that are growing via deposition on the exterior surfaces. Soda-straws and > helictites are fed from internal canals (water-drop diameter in straws; > capillary size in helictites), and can't be expected to show effects that > develop in an external film. Helictites are typically irregularly crooked > (thought to be the result of crystal-growth forces), and are not made of > regularly-spaced annular rings. In helictites, the nearest thing I have > seen to that is the rare "beaded" pattern in which some aragonite > helictites are composed of a string of repeating growths of conical clumps > of diverging crystals (e.g., in Silent Splendor and Breezeway Cave at > Manitou, Colorado). As far as I know, the mechanism that causes beaded > helictites has never been explained, so I can't rule out that development > of their structure may involve subtle chemical effects. In general, > however, helictites and stalactites are often found together, sharing the > same water source, and whether a helictite or stalactite grows from a > given point seems to depend on whether the source flow is enough to form a > hanging drop at the tip (which will make the resulting form a stalactite).
I strongly suspect that > > --Donald > _______________________________________________ > SWR mailing list > [email protected] > http://lists.caver.net/cgi-bin/mailman/listinfo/swr > _______________________________________________ > This list is provided free as a courtesy of CAVERNET _______________________________________________ SWR mailing list [email protected] http://lists.caver.net/cgi-bin/mailman/listinfo/swr _______________________________________________ This list is provided free as a courtesy of CAVERNET
