nurizspace

As the earth’s surface erodes, mineral moleculs in rock dissolve and are washed into the sea. In time these minerals from new rocks , all except sodium chloride which remains dissolved in the water. Over millions of year the sun’s heat has left sodium chloride that makes sea water salty.

Rivers are only slightly salty because of their continuous flow and refill by rainfall, whereas sea water, though it is circulated by tides is held captive in the world’s ocean.