Impact Degassing of H2 on Early Mars and its Effect on the Climate System

Robert M. Haberle, Kevin Zahnle, Nadine G. Barlow, Kathryn E. Steakley

Research output: Contribution to journalArticle

Abstract

Impacts on early Mars can produce H2 and CH4 in the thermal plume. In a thick CO2 atmosphere, collision-induced absorptions between CO2-H2 and CO2-CH4 can boost the greenhouse effect. We construct a simple model of the impact history of Mars and show that for a variety of impactor types and CO2 surface pressures >0.5 bars, postimpact surface temperatures due to H2 alone can exceed the melting point of water for much longer periods of time than from the dissipation of the heat derived from the impactor's kinetic energy. This longer timescale is set by hydrogen escape rather than radiation to space. Cumulatively, the Noachian surface may have been above the melting point of water for millions of years by this mechanism. These greatly extended postimpact warm environments may have played a larger role in the erosion and mineralogy of the surface than previously thought and may partly explain some of the observed fluvial features.

Original languageEnglish (US)
JournalGeophysical Research Letters
DOIs
StateAccepted/In press - Jan 1 2019

Fingerprint

impactors
degassing
mars
climate
melting points
Mars
melting
greenhouse effect
surface pressure
mineralogy
acceleration (physics)
water
surface temperature
kinetic energy
escape
erosion
plumes
dissipation
plume
collision

Keywords

  • Climate
  • Degassing
  • Greenhouse
  • Impacts
  • Mars

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

Impact Degassing of H2 on Early Mars and its Effect on the Climate System. / Haberle, Robert M.; Zahnle, Kevin; Barlow, Nadine G.; Steakley, Kathryn E.

In: Geophysical Research Letters, 01.01.2019.

Research output: Contribution to journalArticle

@article{195625a909154587a0a8e33c5a0a5ee1,
title = "Impact Degassing of H2 on Early Mars and its Effect on the Climate System",
abstract = "Impacts on early Mars can produce H2 and CH4 in the thermal plume. In a thick CO2 atmosphere, collision-induced absorptions between CO2-H2 and CO2-CH4 can boost the greenhouse effect. We construct a simple model of the impact history of Mars and show that for a variety of impactor types and CO2 surface pressures >0.5 bars, postimpact surface temperatures due to H2 alone can exceed the melting point of water for much longer periods of time than from the dissipation of the heat derived from the impactor's kinetic energy. This longer timescale is set by hydrogen escape rather than radiation to space. Cumulatively, the Noachian surface may have been above the melting point of water for millions of years by this mechanism. These greatly extended postimpact warm environments may have played a larger role in the erosion and mineralogy of the surface than previously thought and may partly explain some of the observed fluvial features.",
keywords = "Climate, Degassing, Greenhouse, Impacts, Mars",
author = "Haberle, {Robert M.} and Kevin Zahnle and Barlow, {Nadine G.} and Steakley, {Kathryn E.}",
year = "2019",
month = "1",
day = "1",
doi = "10.1029/2019GL084733",
language = "English (US)",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",

}

TY - JOUR

T1 - Impact Degassing of H2 on Early Mars and its Effect on the Climate System

AU - Haberle, Robert M.

AU - Zahnle, Kevin

AU - Barlow, Nadine G.

AU - Steakley, Kathryn E.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Impacts on early Mars can produce H2 and CH4 in the thermal plume. In a thick CO2 atmosphere, collision-induced absorptions between CO2-H2 and CO2-CH4 can boost the greenhouse effect. We construct a simple model of the impact history of Mars and show that for a variety of impactor types and CO2 surface pressures >0.5 bars, postimpact surface temperatures due to H2 alone can exceed the melting point of water for much longer periods of time than from the dissipation of the heat derived from the impactor's kinetic energy. This longer timescale is set by hydrogen escape rather than radiation to space. Cumulatively, the Noachian surface may have been above the melting point of water for millions of years by this mechanism. These greatly extended postimpact warm environments may have played a larger role in the erosion and mineralogy of the surface than previously thought and may partly explain some of the observed fluvial features.

AB - Impacts on early Mars can produce H2 and CH4 in the thermal plume. In a thick CO2 atmosphere, collision-induced absorptions between CO2-H2 and CO2-CH4 can boost the greenhouse effect. We construct a simple model of the impact history of Mars and show that for a variety of impactor types and CO2 surface pressures >0.5 bars, postimpact surface temperatures due to H2 alone can exceed the melting point of water for much longer periods of time than from the dissipation of the heat derived from the impactor's kinetic energy. This longer timescale is set by hydrogen escape rather than radiation to space. Cumulatively, the Noachian surface may have been above the melting point of water for millions of years by this mechanism. These greatly extended postimpact warm environments may have played a larger role in the erosion and mineralogy of the surface than previously thought and may partly explain some of the observed fluvial features.

KW - Climate

KW - Degassing

KW - Greenhouse

KW - Impacts

KW - Mars

UR - http://www.scopus.com/inward/record.url?scp=85075421566&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85075421566&partnerID=8YFLogxK

U2 - 10.1029/2019GL084733

DO - 10.1029/2019GL084733

M3 - Article

AN - SCOPUS:85075421566

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

ER -