title: Mass-independent isotope effects in planetary atmospheres and the early solar system.
abstract: A class of isotope effects that alters isotope ratios on a mass-independent basis provides a tool for studying a wide range of processes in atmospheres of Earth and other planets as well as early processes in the solar nebula. The mechanism for the effect remains uncertain. Mass-independent isotopic compositions have been observed in O3, CO2, N2O, and CO in Earth's atmosphere and in carbonate from a martian meteorite, which suggests a role for mass-independent processes in the atmosphere of Mars. Observed mass-independent meteoritic oxygen and sulfur isotopic compositions may derive from chemical processes in the presolar nebula, and their distributions could provide insight into early solar system evolution.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0356, USA. mht@chem.ucsd.edu
authors.forename: M H
authors.initials: MH
authors.lastname: Thiemens
mesh_terms: D001272:Atmosphere; D002245:Carbon Dioxide; D002247:Carbon Isotopes; D002248:Carbon Monoxide; D005118:Extraterrestrial Environment; D018535:Mars; D019110:Meteoroids; D008970:Molecular Weight; D009609:Nitrous Oxide; D010103:Oxygen Isotopes; D010126:Ozone; D016083:Planets; D016082:Solar System
chemical_list: D002247:Carbon Isotopes; D010103:Oxygen Isotopes; D002245:Carbon Dioxide; D010126:Ozone; D002248:Carbon Monoxide; D009609:Nitrous Oxide