Organic haze in Earth's early atmosphere: Source of low-13C Late Archean kerogens?

Alexander A. Pavlov, James Kasting, Jennifer L. Eigenbrode, Katherine Haines Freeman

Research output: Contribution to journalArticlepeer-review

89 Scopus citations

Abstract

High concentrations of greenhouse gases would have been required to offset low solar luminosity early in Earth's history. Enhanced CO2 levels are probably at least part of the solution, but CH4 may have played a significant role as well, particularly during the Late Archean era, 2.5-3.0 Ga, when methanogenic bacteria were almost certainly present. Indeed, biological CH4 production should have led to CO2 drawdown by way of a negative feedback loop involving the carbonate-silicate geochemical cycle. We suggest here that the atmospheric CH4/CO2 ratio approached the value of -e11 needed to trigger formation of Titan-like organic haze. This haze was strongly depleted in 13C relative to 12C and was produced at a rate comparable to the modern rate of organic carbon burial in marine sediments. Therefore, it could provide a novel explanation for the presence of extremely low-13C kerogens in Late Archean sediments.

Original languageEnglish (US)
Pages (from-to)1003-1006
Number of pages4
JournalGeology
Volume29
Issue number11
DOIs
StatePublished - Jan 1 2001

All Science Journal Classification (ASJC) codes

  • Geology

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