The West Siberian underground basin is also huge. The territory it occupies could accommodate several large Western European states. Our country has a significant number of smaller basins in the Caucasus, Pamirs, and Tien Shan. These basins are located between mountain ranges. Crystalline rocks come to the surface of the earth, similar to huge plates, but broken by cracks (the Baltic Shield, the Ukrainian crystalline massif, and many others). Water circulates in them through cracks and veins, penetrating deep into the earth. Whole systems of fractured waters are formed. Such waters can appear on earth in the form of springs. Various depressions are formed in the bowels of the earth, where rivers flow and lakes and huge pools of water — seas - rest. This is due to a natural phenomenon called karst. Rain and surface waters, falling into rocks consisting of limestone, dolomite or gypsum, dissolve them.


Initially, small potholes and grooves appear on the surface of the earth. But decades pass, and sometimes hundreds of years, and the water gradually penetrates deeper through small cracks, widening the emptying holes in its path. In this process, a certain role is played by the dissolution of carbon dioxide, which enters it from the air. So, for thousands of years, water and its accompanying carbon dioxide have been able to form caves, grottos, galleries, underground halls, chasms and channels — beds for underground rivers and lakes. Connecting with each other, they create complex labyrinths — karst caves, underground seas. Continuous long-term operation of water, and then the collapse of rocks leads to the formation of deep wells of mines. Crimean speleologists have discovered the Cascade mine on Ai-Petri with a depth of 246 m. A 307 m deep cavity in the Arabica massif has been discovered in Georgia. In France, a group of speleologists led by Pierre-Gicquel discovered and studied a chasm called Pierre's chasm in 1956. The depth of this chasm is truly record—breaking - 564 m. Over time, water can form very large cavities. One of these cavities, a cave system, is located in the U.S. state of Kentucky. Because of its colossal size, it is called Mammoth. The length reaches 240 km. Underground rivers and waterfalls are connected to the Green River above ground. There are also three underground lakes here. There are large caves in Switzerland, Austria, Hungary, Germany, Brazil, and Mexico. Vorontsovskaya Cave in the Caucasus, Krasnaya Cave in the Crimea, and the Kungur ice Cave in the Urals are well known in our country. Karst voids, as a rule, are filled with huge masses of water. Sometimes karst waters appear in the form of springs feeding lakes and rivers. It is generally accepted that their role in natural processes is quite significant. The ancient karst today began to be used for the discharge of waste water and associated waters during oil production. Such waters, having passed through the strata of various terrestrial rocks, are purified and participate in the natural water cycle. Wie ervaren spelers met verantwoord gokken omgaan en welke risico’s bij populaire casinospellen horen, wordt helder uitgelegd in dit artikel, waarin ook aandacht is voor limieten en zelfcontrole. Voor een genuanceerde blik op kansspelen en praktische tips rondom gokken kun je hier lees meer over vinden.