Origin and evolution of the Caves

The formation of a cave depends on the chemical and mechanical work of groundwater and the physical properties of the ground.

All results from the action of chemical and physical agents, being that, in percentage terms, this action can be seen in the ratio of 90% and 10% respectively. More specifically, the dissolution and alteration of limestone through chemical processes take place - through the carbon dioxide dissolved in the water, more oxygen, and even various acids and organic products that come from the soil.

By this infiltration, water loaded with carbon will penetrate through the slots and cracks of the limestone. The CO2 reacts, transforming the calcium carbonate in bicarbonate calcium soluble and transported by the water. With the movements made by cracks and fractures, these will extend slowly, giving openings of variable forms that the work of water will increase with time, forming more cavities in the rock. The physical agents, although considered minimal, deserve citation for the work of structure that exercise: heating and cooling that cause fractures through which penetrate into the water. It is, therefore, obvious that the grotto is not a product of a static phenomenon. Has its birth and evolution until it reaches maturity, and then the destructive process begins until total disappearance.

Galleries and rooms of a cave

Galleries form when water loaded with carbon dioxide, dissolved the limestone and lengthens the initial conduct. With time, while they appear, the first concretions in the ceiling, the water deepens the lowest layers and only the space of ground below remains flooded, digging little by little, meanders that in certain occasions have kilometers of longitude.

The speleothems, the Greek spelaion (cave) and thema (tank), are defined as mineral deposition in caves that are formed basically by chemical processes of dissolution and precipitation. Are the most flashy and colorful underground universe, but their abundance is not always the same as it depends on a variety of situations: the maturity of the cavity, the region where it is located and the height or the climate. These speleothems cover both the ceilings and walls of the cave, as its floor, being formed by two mechanisms of basic deposition: the dripping and the outflow.

The coloring of the speleothems depends on the dimensions of factors such as the presence of organic matter, the action of certain bacteria, some deposits in the crystalline lattice or the presence of metal ions (oxides and hydroxides of iron, magnesium, lead and copper). Based on these and other constraints are established classifications for the various speleothems:

Stalactites


These are the most frequent. The water reaching the roof of a gallery through a slot, due to changes in pressure and temperature, loses carbon dioxide and releases the calcium carbonate around the drop, slowly crating a thin concretion, by which the water flows. It is called tubular when they are too long and with a small-diameter. The development of the stalactite and the evolution of its crystalline system depend on the intensity and constancy of deposition. The rate of growth of these tubular stalactites varies from place to place and from season to season, but, according to studies carried out in various parts of the world, the annual growth of speleothems is in the order of 0.3 mm.

Stalagmites


The water reaching the soil begins to form a stalagmite. They are usually wider than the stalactites and with a less sharpen top. Having its formation associated with stalactites, they show growth rates of the same order. 

Column


When a stalactite reaches the stalagmite below it forms a column.

Cauliflower

Deposits of calcite growing in walls and floors of caves. According to the theory their formation is dependent from the dripping of water from ceilings and correspondent "spraying" of the drop against the floor or wall. This process makes the calcite dissolved in water droplets to rush in an irregular way and scatter on the neighboring stands. Thus, large areas of the floors and walls are covered with these speleothems, usually little consistent, whose final appearance, branched and irregular, recalls the plant where it originated its name. 

Lago da Felicidade
Lago da Felicidade
Capela Imperfeita
Capela Imperfeita

Points of interest