Speleogens

Unlike all the other solution cave features highlighted in The Virtual Cave, speleogens aren’t mineral or crystal deposits. Rather, they are part of the bedrock the cave is formed in, that has been sculpted by erosion or dissolved into distinct interesting shapes. The first photo shows anastomoses in Mammoth Cave, Kentucky. These ceiling channels were the original small tubes in which groundwater began dissolving the cave. Later these converged to form the larger passage beneath.

Hypogene caves, those formed from the bottom up, typically from sulfuric acids like Lechuguilla Cave, often have large and unusual speleogens, such as shown in photos 2 and 3.

Photos 4-7 show more conventional speleogens. These forms are also sometimes called pendants.

Photos 8 and 9 show even more pronounced speleogens in a cave in Borneo. These pendants and pinnacles were probably sculpted by periodic flood water erosion. Heavy deposits of guano around them may also have had a role by providing acids that dissolved some of the bedrock. Photo 10 shows an unusual set of spleogens in a hypogene cave in Thailand.