Lime icicle. Formation of stalagmites and stalactites

Visitors to the karst caves can observe a unique in their beauty spectacle - a group of stalactites and stalagmites. They grow chaotic piles and form into large and small groups. Do you know what it is all about? How are they formed and how are they different?

Let's start with the basics. Why the caves are karstic

The Earth's crust is heterogeneous in composition. At the stage of formation of land and the world ocean, various rocks and minerals were 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 under less extreme conditions. Millions of years, water has been undermining and washing away these rocks, leaving behind large and small voids. So there were caves, which became known as karst. The fact is that karst is an emptiness inside some body. Most of the known caves are of karst origin. However, other processes of cave formation are known, but there are no stalactites or stalagmites in them.

How did the terms "stalactite" and "stalagmite"

The terms "stalactite" and "stalagmite" were introduced by the Danish naturalist Ole Worm. It happened in 1655. Both terms refer to the Greek language. Stalactite is translated as "drip by drop." That is, it is a kind of calcareous icicle hanging from the ceiling of a karst cave. Chemogenous formation sometimes consists not of limestone, but of other sedimentary rocks. In form, the stalactites resemble ice icicles, fringe, thin straws or ridges with multi-level teeth.

Stalagmite in translation means "drop". This is a mineral inflorescence (calcareous) icicle, which grows from the bottom of the cave with a cone or column. Sometimes the main building material for stalagmite is not lime rock, but gypsum or salt. But this is not a frequent occurrence.

Education process

The shape and dimensions 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 penetrates into the karst caves. Rain and snow have to overcome a long and difficult path, washing out calcium and other materials along the way. The pores through which the moisture seeps in are very small. Because of this, water does not run off streams, but drips from the ceiling of caves. Each droplet carries with it a small amount of sedimentary rocks (mostly 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, which in the cave hangs under the arch, or a sedimentary outgrowth appears, rising to meet. As a result, the cave acquires a mystical-fantastic appearance, giving birth to legends about the underworld.

Despite the fact that the process goes everywhere according to one scenario, in the world there are no identical caves. Moreover, each "hall" in the cave is unique. Nature does not allow for repetition.

The speed of education

The formation of stalactites and stalagmites is a long process. According to approximate calculations of scientists, to grow 1 cm, they need about 100 years. The rate of growth depends on the speed of the drop, the humidity of the intra-cavity air, the temperature and composition of the dissolved rocks. Precise calculations of growth can not be made. When trying to research groups of scientists received so contradictory results that it was impossible to bring them to the "common denominator". Since the initial data, such as the intensity of the drop, the height of the fall, the rate of evaporation, the amount of sedimentary material, and so on, constantly changed. Sometimes the calcareous icicle generally stopped growing for several hundred years.

How can stalactites and stalagmites look like?

Stalagmites are always thicker and larger than stalactites, since all the sedimentary rocks that come with water flow down the walls, completing the build-up. In addition, stalactites sometimes fall under their weight, and stalagmites - not.

If the movement of water droplets is not disturbed, the stalactite and stalagmite "weld" into the underground column. Such a calcareous icicle is called stalagnate. Sometimes stalagnata grow together and share rooms with calcareous drapery.

On the inclined caves of the caves, the stalactites are in the form of bands that form sails. They can be smooth and wavy. It is necessary to understand how many caves you will not see, all the stalactites will be unique.