Chlorine stable isotope distribution of Michigan Basin formation waters

The Cl isotope ratio, mass37Cl/35Cl, was measured on 22 formation waters from Mississippian, Devonian, Silurian, Ordovician and Cambrian strata in the Michigan Basin. Because of its resistance to fractionation, the ratio was used to find evidence of mixing of formation waters within the Michigan Basin and between the Canadian Shield and the basin. The δ37Cl composition of waters decreased from +0.05 to −0.55 (per mil difference from SMOC, …