We formulated a couple of theories involving evaporation or rocks falling into the sea and getting knocked about a bit, eventually to the point where some sodium bicarbonate popped out. Nothing was satisfactorily robust, so, I decided to find out.
This is for your benefit as much as mine. For that dinner party. You know.
The salt in the sea comes from:
- Weathering of continents
- Hydrothermal vents, and
- Submarine volcanoes
It's pretty cool! And you can read more here: Why is the sea salty?