The quantities of dissolved salts deposited by rivers in the Earth's oceans have not been unusually large during the past hundred years.

At any given time, all the Earth's rivers have about the same salt levels.

There are salts that leach into the Earth's oceans directly from the ocean floor.

There is no method superior to that based on salt levels for estimating the maximum age of the Earth's oceans.

None of the salts carried into the Earth's oceans by rivers are used up by biological activity in the oceans.