Why sea water is salty

Salt is a mineral compound that is made up of many types of minerals. In reality, what we commonly call “salt” is only one type of salt, but many types of mineral salts can be found in nature. In this way, when we talk about salt, we are referring to a chemical compound that is sodium chloride , and it is a molecule made up of both sodium and chlorine atoms.

When we find this type of salt in nature we call it halite, which is the name of the mineral common salt. However, most of the salt that we find in our life (especially in food) does not come from halite, but from sea salt . When sea water dries, only the liquid component, that is, water, evaporates. Consequently, the rest of the solid components dissolved in this water are separated and in a solid state, and it is called saltpeter.

Saltpeter is composed mainly of common salt (sodium chloride), although it has more minerals that are also naturally dissolved in seawater. When the salt is separated from the rest of the saltpeter, it is then that common salt is obtained, or table salt, in other words, the salt that we use to season food.

Actually, you can find places with salt on earth . However, these are exceptional places, since most of the salt on our planet is concentrated in salty water . This is due to a very simple fact, which is that salt dissolves very easily in water.

At the origin of our planet, all salt was similarly distributed over the incandescent surface of the Earth. But, as the surface cooled and the water on our planet went from a gaseous state to a liquid state, the first seas were formed . Then, the water cycle also began . This water cycle implies that the water from the seas evaporates to form clouds, the clouds generate rain, the rain creates rivers and, finally, the rivers return the water to the sea, thus completing the cycle.

As we have said, salt was originally distributed over the entire surface of the planet. When the water cycle began, the rain caused the salt on the surface to dissolve and be absorbed first by the rivers, which took it upon themselves to transfer it to the seas. However, when the water in the seas evaporated, the salt remained in the sea, so that, as the water cycle repeated itself over and over again, the concentration of salt in the seas was higher, at the same time. that the salt on the earth’s surface was gradually descending. After millions of years, all the salt had been washed away by the water, causing it to be completely concentrated in the seas of our planet.

It is true that there are certain places on the earth’s surface where deposits of natural salt can still be found . This can be due to two different types of causes. On the one hand, it may be the case that it is a place where the water cycle has failed to dissolve the original saltpetre deposits from primordial times. In this way, they are mineral salts that have been in the same place since the time of the creation of our planet.

On the other hand, you can find some valleys or inland seaswhich are also salty. This is because the water cycle has indeed modified the original salt in the area. However, it is an area that, due to its orography, has not been in contact with the largest seas and that are connected to each other. In this way, it is a quantity of salt that has not been able to “escape” from those places, usually because it is found in isolated areas by the mountains. Consequently, just as salt is concentrated in the seas, it is also concentrated in the depressions or isolated valleys of some mountain systems but, in this case, it is salt that has not been able to leave these enclaves despite the millions years that have passed since the water cycle began. It is, for example, what happens in the Dead Sea .