New paper on iron speciation published

Iron speciation is one of our most robust proxies to understand the redox conditions of ancient water columns. This paper by Slotznick et al. (with lab members Erik Sperling and Austin Miller, as well as other collaborators at UC Berkeley, University of Utrecht, and University of Oxford) used magnetic techniques and XRD to probe the specificity of extractions used in iron speciation. The analyses confirmed the specificity of many of the extractions but revealed that the oxalate extraction mainly targets iron-rich clays such as berthierine and chamosite. Intriguingly, the proportion of samples with high amounts of oxalate-extractable iron has declined substantially through geological history, potentially pointing to differences in iron cycling through time. The paper can be accessed here.