Mineralogical and geochemical indicators of anoxic sedimentation conditions in local depressions within the Sea of Okhotsk in the late Pleistocene-Holocene

This paper reports specific mineralogical and geochemical characteristics of deposits from the local depressions of the Derugin Basin. They were formed in an environment with periodic changes from oxic to anoxic conditions and show evidence for the presence of hydrogen sulfide in bottom waters. The deposits of this type can be considered as a modern model for ancient ore-bearing black shale associations. Compared with typical metalliferous black shale sequences, which are characterized by high contents of organic matter, the sediments described here are depleted in the elements of the organophilic association (Mo, Ni, Cu, Zn, V, and U) but have higher Mn contents.