1-s2.0-S0012821X16305854-gr005.jpg

Fig. 5. Standard mixing calculation with a 80 μg/g initial phosphate Cl concentration with an isotope composition of δ37Cl of −0.6, the average of SaU 005, NWA 4864, Zagami, and Tissint (Table 1) and a crustal Cl concentration of 5000 μg/g (Keller et al., 2006). Positive mixing end member δ37Cl is a hypothetical +5‰, which is seen as the maximum perchlorate δ37Cl value on Earth (Jackson et al., 2010) and negative δ37Cl of −14‰, the most negative perchlorate value on Earth (Jackson et al., 2010) and ranging to −51‰, which has been measured in Gale crater (Farley et al., 2016).