When a minning gallery cuts into a natural cavity development, a strong current of fresh air builds up in the works, known in minning terminology as a blowhole(soplao). La florida mine, at the start of the 20th century, discovered an extraordinary cavity, the most attractive in the world, later to be christened with the name of "El Soplao".
Almost always, the caves are formed in carbonated rocks(limestones and dolomites), due to a dissolution process known as karsting. In the exterior too, this transformation leads to a significant midelling lappies or lapis, dolines, potholes, shafts... The mecanism involves the union between the basic minerals comprising these rocks, calcite or dolomite, with certain natural acids, to form a soluble product, calcium bicarbonate, which is transported by water, leading to the formation of gaps. The most common acid involved in this reaction comes from the joining of atmospheric carbon dioxide and water, in other words carbonic acid. In other cases, of organic compounds brought down by water on its way towards the interior or of products generated by the alteration of metal mineralization in the environment, as occurs in El Soplao, which will contribute a fair amount of components that are also going to corrode the carbonated rocks in the subsoil.
The formations embellishing these caverns are generally termed as speleotherms. But straight away, especially in El Soplao, we can distinguish between two types of rock formations: the classical or gravitational and the eccentric or helictite. The former are, in all cases, to do with water falling down by gravity. As it infiltrates from the surface, water penetrates the mountain, filling up with soluble products: calcium bicarbonate, iron oxides, metal salts, etc. When the water reaches the roof of a gallery, it falls but, at the same time, undergoes decompression, precipitating part of its load, thus forming stalactites. The other minerals transported reach the floor, building up a deposit which, in almost all cases, covers a larger surface area since the water splashed a fair part of the surrounding area, thus creating stalagmites. Over time, the rocks deposit in the roof and floor tend to join together, and here we have pillars. In the case of shields, tubes, water seeps through a crack, which is not necessarily rectilinear, creating more or less attractive forms. But this does not only precipitate calcium carbonate in the form of calcite or aragonite, but also other chemical products transported by the water. The result is, at time, a whimsical petrifaction tinged by the most unexpected tones.
The other large group of speleotherms that can form inside caverns that take on an uncommon size in El Soplao are the eccentric type. In this case, the most noticeable morphological characteristic is one of anarchy. The threads of calcite or aragonite are interwoven, making whimsical knots beyond any restriction imposed by Earth's gravity. Both the roof, the walls and the floor brim over rocks deposit of this kind, in all cases being associated with large amounts of clay, taking up airlight pockets in the underground system. There must have been an atmosphere of absolute stillness in El Soplao, where infinite numbers of microdrops of water loaded with bicarbonate ions CO3H- and calcium, Ca2+ would float. The abundant amount of clays is a fact that, apart from being striking, is highly significant in El Soplao cave.
Clays are formed by a series of complex silicates in the phyllosilicate group, accompanied by ions from diverse metals, particularly from iron, which can generate a changing electromagnetic field in the cavern able to mobilize the bicarbonate-calcium ions, causing them to join together and, subsequently, the anarchic precipitation of calcite or aragonite. Another theory postulates a different genesis, relating the eccentric rocks with the arrival in the airlight cavity with tiny amounts of water seeping through a minimum thickness of overflow. As the load precipitates, CaCO3 seals off the small hole through which the water travelled, so that the rock deposits move out laterally to grow, giving rise to an endless number of unlikely forms.
To claim this Earthcache you must go to the published coordenates and send to me the answers for the following questions after visiting the published coordinates:
1. In the given coordenates are a statue, to whom is it dedicated?
2. There you can see two dates. Which?
3. In the given coordenates is a structure whose walls are made of one of the principal materials extract from the cave! What kind of material is that?
4. What is the most important mineral extracted from the mine?
You should take a picture of you making some minning, be creative! After you receive my mail validating your answers you should put it in your log.
The given coordenates are not from inside the cave but in front of one of the major entrances to this extended cave. To visit the caves you must have a permission from the "Federacion Cantabra de Espeleologia" Info or visit it with a tour guide Info