Copper and zinc incorporation mechanisms in diagenetic sedimentary pyrite: environmental and geochemical implications

The objective of this study is to elucidate the molecular-level speciation of Cu and Zn in low temperature pyrites synthesized in conditions mimicking early diagenesis of sediments. Understanding these processes is crucial for reconstructing the timing of seafloor ore deposit formation and ancient ocean composition, as well as developing cost-effective recovery methods based on iron sulfide precipitation at low temperature. To do so, HERFD-XANES and -EXAFS data at both the Cu and Zn K-edges will be collected on pyrites synthesized at different pH ranges representative of various environmental conditions. Preliminary results suggest early segregation of Cu and Zn into insoluble sulfide phases, evolving into complex nanophases upon pyrite formation. Identifying these phases will enhance understanding of Cu and Zn partitioning in marine sediments and support optimized metal recovery strategies from acid mine drainage.