Figure 3
From: Predicting sedimentary bedrock subsurface weathering fronts and weathering rates
Depth profiles of pore water SO4, Ca, Mg, and proton concentrations. Most of the pore water samples were collected from October 2016 to May 2019, but the samples for pH were only from spring 2019. Approximate ranges of three vertical zones: soil, WZ (weathering zone), and FBR (fractured bedrock), are marked with green, orange and blue background, respectively. The pore water SO42− concentration profiles result from pyrite dissolution. The Ca and Mg profiles result mainly from dissolution of carbonate minerals. The pH profiles reflect the effects of proton generation by pyrite dissolution with additional contributions of organic carbon oxidation, and neutralization by carbonate dissolution.
