|Image: Palm Trunc Stalagmite.|
This kind of stalagmites is very common in large caves. There are two preconditions necessary for the growth of this type of stalagmites:
The diameter of the stalagmite depends on the height of the fall and the amount of water. When there is enough water the stalagmites grow with a rather big diameter, But if there is very little water, the stalagmite grows with a rather small diameter.
The dramatic changes of water supply near the surface, leads to a dramatic change in diameters and therefore to this strange sort of stalagmites.