Water is one of the most powerful solvents. It is able to dissolve and destroy any rocks on the earth's surface. Streams of water, streams and drops gradually destroy the granite and stones, when this occurs, the leaching of these soluble components. No solid rock will not be able to withstand the corrosive action of water. It is a long process, but inevitable. Salts that are washed out of the rocks, give the sea water bitter-salty taste.
But why is the sea water salty, and in the rivers fresh?
On this account there are two hypotheses.
The first hypothesis
All impurities, dissolved water, carried by streams and rivers into the seas and oceans. River water is also salty, only salts in her 70 times less than in seawater. Water from the oceans evaporates and returns to earth as precipitation, and dissolved salts remain in the seas and oceans. The process of "delivery" of salts in the sea by rivers has been going on for more than 2 billion years - long enough to "pickle" the entire World ocean.
The river Delta of Klute in New Zealand.
Here Klute is divided into two parts: Matau, Coau,
each of which empties into the Pacific ocean.
Sea water contains almost all the elements that exist in nature. It has magnesium, calcium, sulfur, bromine, iodine, fluorine, small quantities of copper, Nickel, tin, uranium, cobalt, silver and gold. Chemists found in sea water of about 60 elements. But most of all in the sea water contains sodium chloride, or table salt, that's because she and salty.
In favor of this hypothesis is the fact that lakes that do not have flow - too salty.
Thus, it appears that initially the water in the oceans was less salty than it is now.
But this hypothesis does not explain the differences in the chemical composition of seawater and river water in the sea is dominated by chlorides (salts of hydrochloric acid), and in the rivers - carbonates (salts of carbonic acid).
The second hypothesis
According to this hypothesis, the water in the ocean was salty initially, and the fault does not rivers, and volcanoes. Proponents of the second hypothesis believe that during the formation of the earth's crust, when there was a very high volcanic activity, volcanic gases containing vapors of chlorine, bromine and fluorine, spilled acid rain. Thus, the first sea on Earth were... sour. Entering into a chemical reaction with the solid rocks (basalt, granite), acidic water of the oceans is extracted from rocks of alkaline elements - magnesium, potassium, calcium, sodium. Formed salt which was neutralized sea water - it has become less acidic.
With decreasing volcanic activity atmosphere was cleansed of volcanic gases. The composition of ocean water have stabilized at around 500 million years ago - it was salty.
But where do disappear carbonates from river water, falling into the ocean? They use living organisms to build shells and skeletons, and so on, But the chlorides that are prevalent in seawater, they avoid.
Currently, scientists agreed that both of these hypotheses have the right to exist, and not contradict, but complement each other.