Mantle Zenon Has A Story To Tell

[hazelm]

https://www.sciencedaily.com/releases/2018/08/180808134311.htm

 

Mantle degassing and regassing is said to control the habitability of a planet. ..... Substantial regassing began sometime between a few hundred million to 2.5 billion years ago.  The report from Washington University, St Louis, MO, explains the process of regassing and states it as a necessity to a planet to support life.  However, I read the other day that this process is not necessarily a requirement for a habitable planet.  I am sorry I did not save that then but I'll see if I can find it.  Nevertheless, the purpose of this report is to date the process of degassing and regassing.  There is a beautiful picture of Mt Etna erupting.

 

 

[exchemist]

https://www.sciencedaily.com/releases/2018/08/180808134311.htm

 

Mantle degassing and regassing is said to control the habitability of a planet. ..... Substantial regassing began sometime between a few hundred million to 2.5 billion years ago.  The report from Washington University, St Louis, MO, explains the process of regassing and states it as a necessity to a planet to support life.  However, I read the other day that this process is not necessarily a requirement for a habitable planet.  I am sorry I did not save that then but I'll see if I can find it.  Nevertheless, the purpose of this report is to date the process of degassing and regassing.  There is a beautiful picture of Mt Etna erupting.

Yes I think this statement has to be interpreted only very broadly. Life on Earth seems to have started as long ago as 3bn yrs, so it may well have been before the current balance between outgassing and regassing was established. I suppose the broad point is that water and carbon  are necessary at the surface for life to start. But this paper does not suggest these materials were unavailable before the tectonic cycle was in full swing.