sinkholes

  • Sinkholes are geological depressions formed by water erosion in susceptible soils.
  • There are several types of sinkholes: natural, covered, and collapsed, each with unique characteristics.
  • They form in areas with soluble rocks such as limestone and gypsum, especially in karst regions.
  • Sinkholes can be dangerous, causing unexpected collapses that threaten people's lives and safety.

sinkholes in nature

In geology there are several different types of formations. Each one has its unique characteristics and origin. One of them are sinkholes. This is quite a dangerous formation if it catches us off guard. And it is that it is a type of geological depression that occurs in the natural environment and that can form in the center of a canyon or anywhere else.

Therefore, we are going to dedicate this article to tell you everything you need to know about the sinkholes, their characteristics and formation.

Formation of sinkholes

geological depression

Sinkholes are underground pits formed in a catchment area, but there is no external drainage system, so the water begins to erode everything it passes through, whether the underground space or the asphalt itself.

There are three types: wild type, cover type and collapse type. It occurs naturally when there is almost no material or vegetation on the ground, so the water begins to dissolve the surface and eventually a well forms. The cover occurs when there is sand and when the water penetrates the material, the water flows downwards. The collapse type is the most dangerous, because the sediments begin to stir unknowingly, until the top layer finally breaks down and everything around it falls into the hole dug by the water.

In essence, its appearance is related to natural causes, human activities and water. Usually water from heavy rains or water that exists due to low sea level in the area will eventually affect one of the underlying rock layers of the soil, i.e. manages to change some non-surface layers. When this happens, two things can happen that lead to the formation of a sink.

Limestone rock formations
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Everything you need to know about the karst relief

First, it can happen that there is an underground cave in the ground that we step on, although we do not know it, and that it affects the very ceiling. This can be the erosion of the surface that collapses and is eventually exposed. In the second case it can happen because there are no caves, and the action of the water dissolves the rock that firmly holds the soil, and also causes it to collapse, creating these earthly abysses.

Where they occur

sinkholes

If authorities are warned, they may find road signs warning of potential vulnerabilities. Otherwise, pay attention to the ground, as there may be cracks and slight gouge marks. Another way to detect this is if you see plants growing near the cracks, means there is water underneath.

There are many very interesting underwater sinkholes, and there are even some that you can visit if you are sightseeing. These are often called "blue holes" and cover large areas. For example, Pozzo del Mero in Italy is almost 400 meters deep and the Blue Hole of Dean in the Bahamas sinks more than 200 meters.

The downside to sinkholes is that they are dangerous. Of course, it all depends on the type of sinkholes that form, but in cities, they tend to erode to the point of collapse, which is why they eventually lead to the deaths of unsuspecting passersby. why many cars fall to the ground in depth. The most tragic thing is that the corpses of many people who were swallowed by the sinkhole, because the territory is very unstable, will never be recovered.

Surely sometime in your life you have visited a cave.  Caves are beautiful, fascinating and unique environments on earth where we have an endemic ecosystem.  In the caves we can appreciate certain natural formations that are quite impressive for their beauty and uniqueness.  These formations are called stalactites and stalagmites.  Many people consider these geological formations as true works of art of nature.  It is something worth knowing if you have not seen it before, it will surely surprise you.  But how are stalactites and stalagmites different?  How are they formed?  We will answer all these questions throughout this article.  What are stalactites and stalagmites? Although they have similar names, there are quite remarkable differences between them.  Its formation and structure is different.  Stalactites and stalagmites have one thing in common: they are speleotomes.  This concept refers to the fact that they are mineral deposits that are formed in caves after their formation.  The speleotomes arise as a result of the chemical precipitation that arises during the formation of solid elements from a solution.  Both stalactites and stalagmites originate from calcium carbonate deposits.  These formations occur in limestone caves.  It does not mean that it is not the case where it can form in some artificial or anthropic cavities originating in other different mineral deposits.  The main difference between these two formations is the location.  Each one has a different formation process than the other and, therefore, its location within a cave also changes.  We will analyze this in more detail, describing what each one is.  Stalactites We begin with the formations that originate from the ceiling.  Its growth begins at the top of the cave and goes downward.  The start of a stalactite is a drop of mineralized water.  As the drops fall, they leave traces of the calcite behind.  Calcite is a mineral that is composed of calcium carbonate, which is why it precipitates in contact with water.  Over the years, after the fall of successive mineralized drops, more and more calcite is deposited and accumulates.  When this is crowded, we see that it gets bigger and bigger and takes on different shapes.  The most common shape is the cone shape.  The most common is to see a large number of calcite cones with water precipitating from the ceiling.  The size of the cones depends on the amount of water droplets that has been circulating in that area and the time that this flow of drops has been dragging the calcite.  It could be said that stalactites are rock formations that are created from top to bottom.  In the center of the stalactite, there is a conduit through which mineral water continues to circulate.  It is this factor that differentiates them from other geological formations that have a similar appearance.  Stalagmites We now proceed to describe the stalagmites.  On the other hand, they are formations that originate from the ground and develop upwards.  Like the previous ones, stalagmites begin to form through a mineralized drop with calcite.  These falling drops accumulate calcite deposits successively.  The formations here can vary more since they do not have a central conduit like stalactites through which water droplets circulate due to the force of gravity.  One difference is that they are more massive than stalactites.  Due to the formation process, stalagmites have a more rounded shape rather than a cone shape.  It is also more common to see some with irregular formations.  The most common shapes are those straight tubular shapes called macaroni.  Other common formations are the conulitos (they have a structure like a calcified crater), pearls (with a more rounded shape) and some more.  Stalactites and stalagmites are normally facing each other.  It is common to see a stalactite above and perpendicular to it a stalagmite.  This is due to the fact that the drops that are precipitating from the stalactite have traces of calcite that are deposited on the ground to form the stalagmite.  How stalactites and stalagmites are formed We are going to analyze the formation process of both deposits.  As we have mentioned before, they are formed by a process of chemical precipitation.  These precipitating minerals are dissolved in water.  These formations are formed because the CO2 that is dissolved in the rainwater forms calcium carbonate when it comes into contact with the limestone rock.  Depending on the rainfall regime and the level of water infiltration, these formations will occur sooner or later.  It is the rainwater that seeps through the ground and dissolves the limestone rock.  As a result, these droplets give shape to these deposits.  Calcium bicarbonate is very soluble in water and is what is formed after contact with the CO2 that rainwater brings.  This bicarbonate produces an outcrop where the CO2 escapes which, when reacting, precipitates in the form of calcium carbonate.  The calcium carbonate begins to originate certain concretions around the point where the drop falls.  This only occurs in stalactites, as the drops fall due to the force of gravity that forces them to fall to the ground.  Therefore, the drops end up spilling onto the ground.  Where to see these formations You will surely have been fascinated if you have never seen these formations before (which is not the most common).  However, we are going to tell you the places where you can find the largest stalactite and stalagmite formations.  Being a very slow formation, so that they only grow 2,5 cm in length, it takes about 4.000 or 5.000 years.  The largest stalactite in the world can be found in the Caves of Nerja, located in the province of Malaga.  It is 60 meters high and 18 meters in diameter.  It took 450.000 years to form completely.  On the other hand, the largest stalagmite in the world is 67 meters high and we can find it in the Martín Infierno cave, in Cuba.
Related article:
Stalactites and stalagmites

Examples of sinkholes

places to visit

The rock salt that surrounds the Dead Sea or the limestone of the Yucatan Peninsula in Mexico are two other good examples of the natural formation of sinkholes in the world. In Spain, one of its most famous and impressive natural sinkholes is Torcas del Palancar in the province of Cuenca, which It has become an incredible tourist attraction in the Autonomous Community of Castilla-La Mancha.

Furthermore, There are many types of sinkholes that can be formed. For example, a sump is a type of circular sump that is used as a drainage ditch for rainwater and small rivers; Tollos are very common in the Castilla y León area, similar to sinkholes, but the water they collect will form quickly. They are absorbed by the type of rock.

Relief and geology

The formation of sinkholes occurs in soils made of barren rocks formed from clay and limestone, so this is not the only process in calcareous areas. This happens when part of the rainwater becomes groundwater and flows under the rock mass at the same time as the mass that flows through it.

Because rainwater contains carbon dioxide from the atmosphere, carbonation occurs. This carbon dioxide reacts with the calcium hydroxide in the rock and releases water and calcium carbonate. Therefore, As long as the water reaches the required amount, the rocks will dissolve and settle.

These are the basis for the origin of karst modeling, which led to the formation of sinkholes. Surface water and groundwater gradually dissolve the rocks. In this way, galleries and caves are formed that connect the two waters.

Universal Mountains
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Universal Mountains

Due to the gradual dissolution of the rock, its formation can be slow or it can form suddenly due to the collapse of an underground cave. In the second case, it represents a serious danger for the buildings located on the affected land.

About a year ago, one of these phenomena appeared in Guatemala, which caused fear and, as always, came to hasty and wrong conclusions based on the guesswork and voluntary pain that we had conceded. We are constantly bombarded by so-called coming disasters, and the reasons or possible causes are beyond words.


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