Possible discontinuous evolution of atmospheric xenon suggested by Archean barites

The Earth's atmosphere has continually evolved since its formation through interactions with the mantle as well loss of volatile species to space. Atmospheric xenon isotopes show a unique and progressive evolution during Archean that stopped around Archean-Proterozoic transition. Xe isotope composition early been previously documented analysis fluid inclusions trapped within quartz barite. Whether this was continuous or not is unclear, requiring additional analyses ancient samples, which may potentially retain remnants atmosphere. Here we present new argon, krypton isotopic data from suite Proterozoic barites ranging in age 3.5 1.8 Ga, goal providing further insights atmospheric Xe, whilst also outlining potential complications can arise when using record past atmospheres. Xenon released by low temperature pyrolysis crushing two samples presumably formed 2.8 2.6 Ga mass dependent fractionation (MDF) 11‰.u −1 3.4‰.u , respectively, relative modern If contemporaneous respective age, significant difference degree between provides supporting evidence for plateau MDF-Xe 3.3 followed rapid at 2.8–2.6 Ga. This sharp decrease suggests discontinuous temporal isotopes, could have far reaching implications regarding current physical models • Crushing step-heating allow separation primary secondary components. Barites contain fractionated signature. New Xe. All various mono-isotopic 131 excesses correlated their U content. Spallogenic contribution complicates effective use Ba dating system.