| Cave showerheads are
a fairly rare formation generally only found in tropical caves. They've
been noted in Brazil, Mexico, Puerto Rico, and especially from Borneo.
They sprout from the ceiling at a seep site. The ones below are from a
cave in Gunung Buda, Borneo. It is in the form of a hollow cone, narrow
above and broad below, not unlike a bamboo Chinese hat. It measures approximately
half a meter long and one meter in diameter.
All surfaces of the Buda showerhead appear to be covered with fine calcite botryoids (popcorn-like nodules), most likely the products of seep water issuing through the spongy matrix of the speleothem. Presumably, the conical shape is due to 1) the downward flow of seep water under the influence of gravity, and 2) the preferential deposition of calcite on the speleothem's outer surface, furthest from the seep, where carbon dioxide partial pressure and humidity are at their lowest. In Deer Cave, wihtin Gunung Mulu National Park, a showerhead previously observed on British expeditions is the source of a spectacular falls (lower right photo). This specimen clearly
has a much larger volume of water issuing from it than that observed
at Buda. This showerhead likewise appears to be more elongated and cylindrical
in shape and features a robust lower rim that is broader than the remainder
of the formation.
Cave showerheads should not be confused with simple seeps that often
occur in conjunction with flowstone or drapery deposits and which may
issue high volumes of water following heavy rains.
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Created: November 19, 1995 Modified March 22, 2002 |