Processes of Early Diagenesis in the Arctic Seas (on the Example of the White Sea)

During an early diagenetic stage of sedimentation, a continuous exchange between bottom water and pore solution happens. Throughout the diagenetic stage, an oxygen, SO42−, Ca2+, and Mg2+ diffuse into pore solution from near-bottom water, but the gases generated within sediments (CO2, NH3, H2S, CH4, etc.), and other pore waters’ components (Fe2+, Mn2+) are transferring from surface sediments into near-bottom water. At the same time, as a result of some ions’ oversaturation, a precipitation from pore water of a number of chemical compounds takes place followed by formation of authigenic minerals. Their composition depends on oxidation-reduction conditions within sediments. In oxidizing conditions (in upper sediment layers), ferromanganese mineral associations, as well as glauconite, phosphates, etc., are formed. As the environment becomes reducible after loss of free oxygen due to diagenetic processes, mainly, metal sulfides and carbonate minerals are formed. Such is an idealized scheme of transformation of seawater into pore waters in a humid zone.