Home – Home – Jornals – Geography and Natural Resources 2022 number 3

Results from studying 13 lithological cores from the Kaliningrad Bay of the Baltic Sea are presented. In the cores, the textural features, the grain-size distribution of sediments, the natural moisture, the content of organic matter and vivianite mineral were determined. The study revealed a pattern characteristic of all cores concerning changes in the grain-size distribution of sediments in the depth of their occurrence: in the upper part (to a depth of 32-65 cm), there occur sandy (0.25-0.063 mm) sediments underlain by homogeneous, organic-rich silts (less than 0.063 mm) of olive shades. Changes in the other parameters were also observed in approximately the same layers. Thus, the organic matter content in the upper (0-65 cm) layer averages 6 %, and in the deeper silty sediments, 29 %. Moisture values in the upper layer vary from 45 to 90 %, in the lower - from 90 to 185 %. Formations of the vivianite mineral occur exclusively in the lower layers of sediments. Based on the identified changes in the sedimentary layer, two lithostratigraphic divisions are distinguished: the lower (I) and upper (II) members corresponding to different stages of sedimentation. The lower member formed during the period of predominance of the river flow and is composed of plastic, olive-colored silts identified as “sapropel formations”. They are classified as a mineralized type of sapropel with an ash content of 70 to 87 %. The thickness of the sapropel layer averages about 1 m. Sapropel formations were identified in all columns, which suggests that they have a large distribution in the sedimentary layer.