Showerheads

Cave showerheads are a rare type of stalactite generally found in tropical caves, with a few examples known from temperate climates. They’ve been noted in Brazil, Puerto Rico, the Phillippines, and especially from Borneo in the Gunung Mulu and Buda caves. They sprout from the ceiling at a seep site. The tropics likely favors their formation due to high influx of water and its seasonality. In the wet season the water probably serves to enlarge the feeding tube while low flow in dry seasons likely encourages more deposition. This occurs furthest from the seep, where carbon dioxide partial pressure and humidity are at their lowest.

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.

The first photo shows a classic showerhead from the Philippines in dry-season flow. Photo 2 shows a close-in view of the same showerhead. Interestingly this one is surrounded by spathites, and as well in photo #3 from a cave in Puerto Rico. Perhaps the presence of aragonite is a factor in the formation of both these phenomena.

Photos 4-8 are from Borneo and further show the diversity of showerhead forms. Two are in the form of a hollow cone, narrow above and broad below, not unlike the bamboo hats popular in some Asian countries. The one in photo #4 shares the relative symmetry of the typical showerhead throat, though dry at this time of year (winter). Photo #5 it is much more asymmetrical and may be caused by a different mechanism, whereby roots reach into a cave, creating a void, that is then lined with calcite which leaves a tube that is able to continue seeping water, such as seen in photo #6. Over time the tree might die and the roots decay, leaving a larger void. Photo #7 shows an unusual cluster of showerheads that may have been formed this way. Of course, it is also possible that an existing, seep-formed showerhead was simply invaded by a tree root seeking an even more reliable source of water.

Photo 8 is also from Borneo. UK photographer Robbie Shone shot this striking, active showerhead in Gunung Mulu National Park.

Photo 9 was contributed by German caver Liviu Valenas and shows a strking red-throated showerhead in a cave in Laos.

Photo #10 shows another asymmetrically formed showerhead with a bathtub beneath it in a cave in Missouri, a rare showerhead occurrence in the United States, that is also not in a tropical climate. It might owe its formation to the hypothesized tree root origin.