Principal component analysis indicates that controlling factors of hydrochemistry differs across zones. Principal component 1 (PC1) is described by geo-chemical weathering products and evaporites or marine-sourced precipitations whereas Principal component 2 (PC2) depends on variables affecting isotopic composition (evaporative influence, type of precipitation, etc.) as well as Si. The confidence ellipses are shown for each zone and represent the 95% confidence region that the mean for each zone will be located within the ellipse. DOI: https://doi.org/10.1525/elementa.290.f10