Visitors to karst caves can watch a spectacle unique in its beauty - groups of stalactites and stalagmites. They grow into chaotic piles and form large and small groups. Do you know what it is? How are they formed and how do they differ from each other?
Let's start with the basics. Why karst caves
The earth's crust is heterogeneous in composition. At the stage of the formation of land and the oceans, various rocks and minerals formed. For example, volcanic activity with high temperature and pressure led to the appearance of basalt and granite. But deposits of water-soluble rocks, such as limestone, chalk or gypsum, were formed in less extreme conditions. For millions of years, water has been grinding and leaching these rocks, leaving behind large and small voids. So there were caves, which began to be called karst. The fact is that karst is a void inside a body. Most of the famous caves are of karst origin. However, other processes of cave formation are known, but there are no stalactites and stalagmites in them.
How did the terms "stalactite" and "stalagmite" appear
The terms “stalactite” and “stalagmite” were coined by Danish naturalist Ole Worm. It happened in 1655. Both terms refer to the Greek language. Stalactitis translates as "dripping drop by drop." That is, this is a kind of calcareous icicle hanging from the ceiling of a karst cave. A chemogenic formation sometimes consists not of limestone, but of other sedimentary rocks. In shape, stalactites resemble icicles, fringe, thin straws or ridges with multilevel teeth.
Stalagmite in translation means "drop". This is a saponified mineral (calcareous) icicle that grows cone or column from the bottom of the cave. Sometimes the main building material for stalagmite is not calcareous rock, but gypsum or salt. But this is not a frequent occurrence.
Education process
The shape and size of calcareous growths and icicles depend on the size of the cave and its location. Even in the densest rock there are cracks and microcracks through which water seeps into the karst caves. Rain and snow have to overcome a long and difficult journey by washing calcium and other materials along the road. The pores through which moisture seeps in are very small. Because of this, water does not run away in streams, but drips from the ceiling of the caves. Each droplet carries with it a small amount of sedimentary rocks (mainly limestone). Then the drop evaporates, and the rock dissolved in it remains on the ceiling or falls to the floor. Thus, a calcareous icicle is created that hangs in a cave under the arch, or a sedimentary outgrowth rises towards it. As a result, the cave takes on a mystical and fabulous appearance, giving birth to legends about the underworld.
Despite the fact that the process is going on everywhere according to one scenario, the world does not have the same caves. Moreover, each “hall” in the cave is unique. Nature does not allow repetition.
Education rate
The formation of stalactites and stalagmites is a long process. According to rough estimates, scientists need about 100 years to grow by 1 cm. The growth rate depends on the speed of the droplet, the humidity of the intra-cave air, the temperature and composition of the dissolved rocks. Accurate growth calculations are impossible. When trying to research a group of scientists received so contradictory results that it was impossible to bring them to a “common denominator”. Since the initial data, such as droplet intensity, drop height, evaporation rate, amount of sedimentary materials and so on, constantly changed. Sometimes a limy icicle generally stopped growing for several hundred years.
What stalactites and stalagmites can look like
Stalagmites are always thicker and larger than stalactites, since all sedimentary rock that has fallen with water flows down the walls, building up a growth. In addition, stalactites sometimes fall under their own weight, while stalagmites do not.
If the movement of water droplets is not disturbed, then stalactite and stalagmite "solder" into an underground column. This calcareous icicle is called a stalagnate. Sometimes stalagnates fuse together and divide the halls with calcareous drapery.
On the inclined arches of the caves, stalactites are in the form of stripes that form sails. They can be smooth and wavy. You need to understand how many caves you explore, all stalactites will be unique.