| Abstract: | Abstract— We used the nuclear reaction 37Cl (n,γ) 38Ar, achieved during neutron irradiation for dating meteorites by the 39Ar‐40Ar technique, to calculate the elemental Cl concentration of 132 samples of 94 different meteorites (mostly finds) representing several different classes. determined k and ca concentrations are also reported. Total Cl] varies considerably, both among meteorites of the same class and among different meteorite classes. The range in Cl] is approximately 15–177 ppm for ordinary chondrites; approximately 24–650 ppm for enstatite chondrites; approximately 4–177 ppm for eucrites; approximately 7–128 ppm for mesosiderites; approximately 35–268 ppm for acapulcoites and lodranites; and approximately 12–507 ppm for winonaites and iron silicates. As expected, most differentiated meteorites have lower Cl] compared to chondrites and iron silicates. Analyses of 11 interior samples (～0.1 g each) of a large L6 chondrite varied over 68–129 ppm, which is a measure of the homogeneity of Cl distribution. By evaluating Ar release during stepwise sample degassing, we separated the Cl into low‐temperature and high‐temperature components, the former of which may consist of terrestrial contamination. Most samples show low‐temperature Cl concentrations of <40 ppm, but for several samples terrestrial Cl contamination constitutes significant fractions of the total Cl. Among most differentiated meteorites, finds show considerably greater low‐temperature Cl] compared to falls. |
