Primordial Noble Gases in Chondrites: The Abundance Pattern Was Established in the Solar Nebula

Abstract

Ordinary chondrites, like carbonaceous chondrites, contain primordial noble gases mainly in a minor phase comprising ≤0.05 percent of the meteorite, probably an iron-chromium sulfide. The neon-20/argon-36 ratios decrease with increasing argon-36 concentration, as expected if the gas pattern was established by condensation from the solar nebula, and was negligibly altered by metamorphism in the meteorite parent bodies. Meteoritic and planetary matter apparently condensed over a substantial range of temperatures.