title: Triassic-Jurassic atmospheric CO2 spike.
abstract: I question the claim by Tanner et al. that atmospheric CO2 levels remained constant across the Triassic-Jurassic boundary on the grounds of problems with stratigraphic completeness and contamination with atmospheric methane. Because methanogenic CH4 has a light isotope composition and oxidizes readily to CO2, methane-clathrate dissociation and oxidation events cannot be detected by palaeobarometers that use the carbon-isotope composition of palaeosol carbonate.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Retallack
mesh_terms: D001272:Atmosphere; D005075:Biological Evolution; D002245:Carbon Dioxide / Q000737:chemistry; D005580:Fossils; D017752:Greenhouse Effect; D008697:Methane; D018515:Plant Leaves; D013995:Time
chemical_list: D002245:Carbon Dioxide; D008697:Methane