Degassing of reduced carbon from planetary basalts

Diane T. Wetzel*, Malcolm J. Rutherford, Steven D. Jacobsen, Erik H. Hauri, Alberto E. Saal

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

Degassing of planetary interiors through surface volcanism plays an important role in the evolution of planetary bodies and atmospheres. On Earth, carbon dioxide and water are the primary volatile species in magmas. However, little is known about the speciation and degassing of carbon in magmas formed on other planets (i.e., Moon, Mars, Mercury), where the mantle oxidation state [oxygen fugacity (fO2)] is different from that of the Earth. Using experiments on a lunar basalt composition, we confirm that carbon dissolves as carbonate at an fO2 higher than -0.55 relative to the iron wustite oxygen buffer (IW-0.55), whereas at a lower fO2, we discover that carbon is present mainly as iron pentacarbonyl and in smaller amounts as methane in the melt. The transition of carbon speciation in mantle-derived melts at fO2 less than IW-0.55 is associated with a decrease in carbon solubility by a factor of 2. Thus, the fO2 controls carbon speciation and solubility in mantle-derived melts even more than previous data indicate, and the degassing of reduced carbon from Fe-rich basalts on planetary bodies would produce methane-bearing, CO-rich early atmospheres with a strong greenhouse potential.

Original languageEnglish (US)
Pages (from-to)8010-8013
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number20
DOIs
StatePublished - May 14 2013

Keywords

  • Experimental petrology
  • Hydrogen
  • Iron carbonyl
  • Magmatic volatiles

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Degassing of reduced carbon from planetary basalts'. Together they form a unique fingerprint.

Cite this