The evolution of early diagenetic processes at the Mozambique margin during the last glacial-interglacial transition

The Mozambique continental margin experienced large variations in sedimentation rates, primarily due to re-routing of sediment deposition from the Zambezi River during last glacial-Holocene transition. As changes accumulation and organic matter impose a strong control on formation authigenic minerals sediment, distribution these may reflect regional paleoenvironmental paleoclimatic evolution. Combining geochemical analyses porewaters sediments with reactive transport modeling approach, we reconstruct depositional history its effect pyrite other biogeochemical transformations at site over past 27 kyr. Fitting model match observed patterns, most importantly pyrite, allowed for reconstruction sulfate-methane transition zone depth, which migrated response deposition. Changes quickly affected organoclastic sulfate reduction associated formation, but anaerobic methane oxidation subsequent occurred lag order thousands years. Model results reveal high diagenetic reaction rates representative near-shore environments late glacial maximum, setting typical offshore low present day. Notably, remnants dissolved iron pools produced still shape processes below today. Since deglacial shelf-flooding corresponding along margins worldwide, our analysis highlights important role non-steady state diagenesis relevance paleoceanographic interpretation cores experiencing input.