Abstract Details
(2020) Can Volcanism Build Hydrogen-Rich Early Atmospheres?
Liggins P, Shorttle O & Rimmer P
https://doi.org/10.46427/gold2020.1555
The author has not provided any additional details.
01c: Room 1, Tuesday 23rd June 00:33 - 00:36
Philippa Liggins
View abstracts at 3 conferences in series
Oliver Shorttle View all 7 abstracts at Goldschmidt2020 View abstracts at 12 conferences in series
Paul Rimmer
Oliver Shorttle View all 7 abstracts at Goldschmidt2020 View abstracts at 12 conferences in series
Paul Rimmer
Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.
Submitted by My Riebe on Sunday 21st June 07:04
Could you explain a bit more why the high H2 episodes on Earth and Mars ended?
Thank you. In the case of Mars, the window of sustained volcanism was probably relatively short; once the volcanic flux dropped below ~20% of the modern Earth's rate, a H2-rich atmosphere would be unsustainable. On Earth, any H2-rich episode would have ended with the GOE as the photochemistry assumptions we use assume an anoxic atmosphere; in the presence of oxygen the H2 fractions produced by Earth's volcanism are quickly removed via photochemical reactions.
Could you explain a bit more why the high H2 episodes on Earth and Mars ended?
Thank you. In the case of Mars, the window of sustained volcanism was probably relatively short; once the volcanic flux dropped below ~20% of the modern Earth's rate, a H2-rich atmosphere would be unsustainable. On Earth, any H2-rich episode would have ended with the GOE as the photochemistry assumptions we use assume an anoxic atmosphere; in the presence of oxygen the H2 fractions produced by Earth's volcanism are quickly removed via photochemical reactions.
Submitted by Tomohiro Usui on Monday 22nd June 22:42
How can you produce a warm Mars condition in the high-H2 atmosphere and what exactly green-house effect do you think of ? Do you assume CO2-H2 collision-induced absorption?
Thank you for your question. Yes, we assume CO2-H2 collision-induced absorption to produce warm Martian conditions. Work by Wordsworth et al., 2017 and Hayworth et al., 2020 (and several others) suggests that H2 fractions on the order of 5% in a CO2 atmosphere is sufficient to generate a warm early Mars, given certain pressure constraints, using CO2-H2 CIA heating.
How can you produce a warm Mars condition in the high-H2 atmosphere and what exactly green-house effect do you think of ? Do you assume CO2-H2 collision-induced absorption?
Thank you for your question. Yes, we assume CO2-H2 collision-induced absorption to produce warm Martian conditions. Work by Wordsworth et al., 2017 and Hayworth et al., 2020 (and several others) suggests that H2 fractions on the order of 5% in a CO2 atmosphere is sufficient to generate a warm early Mars, given certain pressure constraints, using CO2-H2 CIA heating.
Submitted by Tomohiro Usui on Monday 22nd June 22:44
How can you produce a warm Mars condition in the high-H2 atmosphere and what exactly green-house effect do you think of ? Do you assume CO2-H2 collision-induced absorption?
How can you produce a warm Mars condition in the high-H2 atmosphere and what exactly green-house effect do you think of ? Do you assume CO2-H2 collision-induced absorption?
Submitted by Viacheslav Zgonnik on Tuesday 23rd June 07:42
Have you considered that early H2-rich atmosphere could be also the result of degassing of deep-seated (or primordial) hydrogen, which is being trapped during the Earth formation? (for examples and references I invite you to see the section 3.1 of my recent review).
It is certainly possible that other long-term sources of H2 could contribute to forming H2-rich atmospheres. In our paper (in review), we compare the scales of some of these H2 fluxes (e.g., from serpentinisation & metamorphism) to those generated through volcanism (though not nearly as thoroughly as in your review!), and find that volcanism is likely to be the largest H2 input to a prebiotic atmosphere. Deep-seated H2 could certainly be another of these sources, but until more research is done as to how large a flux of H2 this source contributes to the atmosphere, it's importance compared to volcanism cannot be determined.
Have you considered that early H2-rich atmosphere could be also the result of degassing of deep-seated (or primordial) hydrogen, which is being trapped during the Earth formation? (for examples and references I invite you to see the section 3.1 of my recent review).
It is certainly possible that other long-term sources of H2 could contribute to forming H2-rich atmospheres. In our paper (in review), we compare the scales of some of these H2 fluxes (e.g., from serpentinisation & metamorphism) to those generated through volcanism (though not nearly as thoroughly as in your review!), and find that volcanism is likely to be the largest H2 input to a prebiotic atmosphere. Deep-seated H2 could certainly be another of these sources, but until more research is done as to how large a flux of H2 this source contributes to the atmosphere, it's importance compared to volcanism cannot be determined.
Sign in to ask a question.