<p>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.</p>

CC BY-SA 4.0
2022-07-13T22:41:10.057Z
So the ocean gets less deep over time? Because the ocean floor is getting higher with the salt buildup and formation of new surface
Groveish
CC BY-SA 4.0
2022-07-14T04:51:14.007Z
@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.
David Hammen
CC BY-SA 4.0
2022-07-06T15:04:38.093Z
2022-07-06T15:04:38.093Z
David Hammen
<p>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?</p>

CC BY-SA 4.0
2022-07-06T20:05:14.157Z
Related if not duplicate: https://earthscience.stackexchange.com/q/20432/18081
Jean-Marie Prival
<oceanography>
If the saturation point of saltwater is 26%, why aren't oceans getting saltier over time?
Groveish
# If the saturation point of saltwater is 26%, why aren't oceans getting saltier over time?

(Asked by: username_0 on 2022-07-06)

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?

**Tags:** oceanography

> **Comments:**
> **username_1**: Related if not duplicate: https://earthscience.stackexchange.com/q/20432/18081  

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## 1 answers

### Answer by username_2 on 2022-07-06. Score: 4

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.

> **Comments:**
> **username_0**: So the ocean gets less deep over time? Because the ocean floor is getting higher with the salt buildup and formation of new surface  
> **username_2**: @username_0 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.  

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