What is the relationship between volcanic activity and the origin of Earth's oceans?
1 Answer
"The best current thinking is that volatiles (elements and compounds, including water, that vaporize at low temperatures) were released from the solid phase as the earth accreted." - James C. G. Walker of the University of Michigan.
Explanation:
A very good discussion of the various theories is here:
https://www.scientificamerican.com/article/what-do-we-know-about-the/
"Volcanoes release water and carbon dioxide to the atmosphere and ocean. Subduction of sediments rich in volatiles takes place at deep ocean trenches. The sinking of oceanic crust at subduction zones carries water and carbon dioxide back into the mantle. These processes can all be seen at work today."
"In short, icy cometary material probably has not been important in providing water for the earth's oceans, but there is little sure knowledge in this field."
