The reason why the ocean is salty is not that there is a mysteriously large amount of salt on Earth.The amount of salt on the earth’s surface is actually quite manageable. Nevertheless, there is a mysterious poetry about what things dissolve and end up in the sea. Again, that is exactly what we would expect.
No, it’s so simple:
This is Halit.
A type of rock that happens to be mostly salt. Rain that hits Halit on the ground dissolves it and carries it down to the ocean.
Sodium chloride is a naturally occurring, ordinary rock called halit.It is just another mineral such as quartz or feldspar. In the past, it (and its component sodium) was even more common on the Earth’s crust than it is today, but unlike the other minerals that are also or more common, it dissolves easily in water, at temperatures and under the conditions common on Earth, while quartz does not.
Therefore, Halit, not quartz, tended to dissolve in rainwater flowing over the land and be washed down into rivers, lakes, and so on, until it was no longer so common on the surface, but accumulated in the oceans.And sodium from rocks in combination with chlorine, as sodium chloride, also slowly dissolves.
So also other water-soluble minerals, such as calcium chloride, magnesium chloride, potassium oxide, calcium carbonate and so on.They are also found in seawater, only in smaller quantities, because they are less soluble and/or less common.
That’s it.Nothing magical, rare or special about it.
If the earth had seas of ammonia that would rain over the land, silver chloride would dissolve more in it, while sodium chloride would be dissolved less.As well as other ammonia-soluble minerals that are more common on the earth’s surface, but you already understand. The ammonia ocean would be full of other minerals such as silver chloride, instead of sodium chloride.
It’s just like that. Sodium chloride is a mineral.A stone. But it dissolves in the ordinary liquid, which strikes on this planet much more often than another.
In any case, the water with its dissolved minerals runs into the ocean, then it evaporates, but the minerals cannot evaporate, so over billions of years the amount that has built up to what it is today.
Why it doesn’t get saltier
This salinity is no longer increasing very quickly, as most of the surface salt has already been flushed into the oceans.New halit is released only gradually, just like rocky sodium sources such as granite, but according to the same process, the old salt destroys as part of the ocean that is lost via plate tectonics. Some of the water is returned through hot springs and other springs, but without the salt.
And it is no coincidence that the mineral in seawater is the most important mineral for human nutrition.We have evolved to need sodium chloride because it is in the ocean, where life is thought to have begun. Life on a planet where rain is ammonia will develop and need the minerals that dissolve in ammonia.