<p>Reactions in ocean floor hydrothermal systems are a significant contributor to the mass balance of several major elements in the oceans, in particular magnesium, calcium, sodium, potassium and sulfate. Magnesium and sulfate are removed from the circulating seawater and calcium, sodium and potassium and added.</p>

<p>What are the principal reactions which take place in hydrothermal systems to achieve the mass transfers stated above? I know that precipitation of magnesium silicate clays is significant for the loss of magnesium but I have but unable to find much information on the others.</p>

CC BY-SA 3.0
2017-01-14T20:08:48.547Z
Are you talking about hydrothermal activity in ocean spreading systems? Black smokers and the likes?
Gimelist
CC BY-SA 3.0
2017-01-15T10:15:40.047Z
@Michael Yes I am.
bon
CC BY-SA 3.0
2017-01-16T02:19:05.787Z
I don't remember the exact details, but magnesium is trapped in clays and sulfate in anhydrite. Sodium and potassium are added because of epidotisation - you take a bunch of feldspars and make epidote out of them, so the Na and K and leached out. Calcium by itself is also very soluble so it's added to the fluids. This is a very chlorine-rich fluid, so all of the usual Cl-soluble stuff goes to the fluid. This is tangentially related to what I did in my masters, so I think I can dig out a review paper that summarises this if you want. Look up a rock called spilite - the alteration product.
Gimelist
CC BY-SA 3.0
2017-01-20T04:57:55.040Z
It was written about hydrothermal, though. And your question is unclear.
Takahiro Waki
<oceanography><geochemistry><hydrothermal-vents>
What reactions change seawater composition in hydrothermal systems?
bon
# What reactions change seawater composition in hydrothermal systems?

(Asked by: username_0 on 2017-01-12)

Reactions in ocean floor hydrothermal systems are a significant contributor to the mass balance of several major elements in the oceans, in particular magnesium, calcium, sodium, potassium and sulfate. Magnesium and sulfate are removed from the circulating seawater and calcium, sodium and potassium and added.

What are the principal reactions which take place in hydrothermal systems to achieve the mass transfers stated above? I know that precipitation of magnesium silicate clays is significant for the loss of magnesium but I have but unable to find much information on the others.

**Tags:** oceanography, geochemistry, hydrothermal-vents

> **Comments:**
> **username_1**: Are you talking about hydrothermal activity in ocean spreading systems? Black smokers and the likes?  
> **username_0**: @Michael Yes I am.  
> **username_1**: I don't remember the exact details, but magnesium is trapped in clays and sulfate in anhydrite. Sodium and potassium are added because of epidotisation - you take a bunch of feldspars and make epidote out of them, so the Na and K and leached out. Calcium by itself is also very soluble so it's added to the fluids. This is a very chlorine-rich fluid, so all of the usual Cl-soluble stuff goes to the fluid. This is tangentially related to what I did in my masters, so I think I can dig out a review paper that summarises this if you want. Look up a rock called spilite - the alteration product.  
> **username_2**: It was written about hydrothermal, though. And your question is unclear.  

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