Isotopic composition of natural and synthetic chlorate (?18O, ?17O, ?37Cl, 36Cl/Cl): Methods and initial results

Natural chlorate (ClO3?) is widely distributed in terrestrial and extraterrestrial environments. To improve understanding of the origins distribution ClO3?, we developed tested methods to determine multi-dimensional isotopic compositions (?18O, ?17O, ?37Cl, 36Cl/Cl) ClO3? then applied samples natural nitrate-rich caliche-type salt deposits Atacama Desert, Chile, Death Valley, USA. Tests with reagents artificial mixed indicate stable-isotope ratios were minimally affected by purification processes. Chlorate extracted from had ?18O = +7.0 +11.1‰, ?17O +5.7 +6.4‰, ?37Cl ?1.4 +1.3‰, 36Cl/Cl 48 × 10?15 104 10?15. Valley ?6.9 +1.6‰, +0.4 +2.6‰, +0.8 +1.0‰, 14 44 Positive values that its production involved reaction O3, while Cl composition consistent a tropospheric or near-surface source Cl. The are positively correlated, as those ClO4? NO3? same localities, possibly indicating variation relative contributions O3 O formation oxyanions. Additional analyses could provide stronger constraints on mechanisms and/or post-formational alterations, applications for environmental forensics, global biogeochemical cycling Cl, oxyanions detected Mars.