From what I read they've been at 3.5% salt equilibrium for millions of years. How is this possible when rivers are constantly flowing dissolving salt into them?
1 Answer
$\begingroup$
$\endgroup$
2
Because salt gets buried over time. Most of the salt we mine is old seas / oceans that dried up and then got buried. Subduction zones carry salt-laden and water-laden sediments very deep underground. The water tends to escape by volcanism. The salt does not.
-
$\begingroup$ So the ocean gets less deep over time? Because the ocean floor is getting higher with the salt buildup and formation of new surface $\endgroup$– GroveishJul 13, 2022 at 22:41
-
$\begingroup$ @Groveish Google "subduction zone". The continents are in general much older than are the oceans. The oldest continental crust is over 3 billion years old. The oldest ocean crust is less than 200 million years old. $\endgroup$ Jul 14, 2022 at 4:51