Diagenetic overprint of paleoceanographic proxies
Early diagenetic processes are not restricted to the sediment/water interface or shallow aquatic deposits but can well extend into deeper layers of the sediment. In this way the primary sediment composition can be heavily overprinted several hundreds to thousands of years after deposition. The most important biogeochemical/early diagenetic that potentially occur over depth as well as the particular impact on the cmposition of the sedimentary solid phase are shown in the figure below.
Schematic representation of redox zonation in marine sediments as well as the most important early diagenetic processes for the alteration of the primary sediment composition and for the formation of secondary signals in the sedimentary solid phase. (taken from Kasten et al., 2003)
Understanding and quantifying these processes is of the utmost importance for accurately interpreting sedimentary records and archives both with respect to properly reconstructing paleoceanographic conditions (e.g. productivity, sea-surface temperatures, salinity, etc.) as well as the paleoenvironment of the water column and the sediment at the time of deposition (e.g., oxic, anoxic, sulfidic). For this purpose we investigate and quantify geochemical and biogeochemical processes in a broad range of different depositional environments (e.g., oligotrophic to high-productivity systems, coastal via slope to open ocean settings, high and low sedimentation environments, oxic/anoxic/sulfidic ocean areas).