Przebieg sedymentacji w zbiorniku Ferdynandowa podczas interglaciału mazowieckiego

Abstract

DEPOSITION IN THE FERDYNANDÓW BASIN DURING THE MAZOVIAN INTERGLACIALSummaryDeposits from three bore-holes (A, B, and C) have been studied. The thickness of the deposits is 25, 18,75 and 27.4 m in the A, B, and C bore-holes respectively. Lithological and geochemical analylses have been carried out for the deposits classified into the Mazovian interglacial. Following the lithological analysis 6 beds have been distinguished within the interglacial deposits of C bore-hole. The sedimentological parameters show values characteristic of a fluvial depositional environment. The bottom of the series, is formed by a, coarse-grained silt bed, clay-rich with the sandy matter content increasing towards the top. This bed is, followed by fine and medium-grained sands. Small variations of the sorting and skewness coefficients may be indicative of some hydrodynamic equilibrium. Next come very well sorted almost uniform sands. Local changes in the depositional conditions are indicated by the gyttja found at the top of this bed. The successive beds overlying the gyttja are built of unequigranular sands followed by sandy silts. The distribution of trace elements in the upper part of the uppermost bed shows some similarities to the profile of the turfy-podsol. It is characterized by a scarcity of chemogenic carbonates along with an iron and manganese concentration. At the depth of 2,3–3.0 m there occurs a horizon of secondary precipitation ferruginous-concretions. The Mazovian interglacial deposits of the bore-hole profile are represented by a 18 m thick series consisting of silts, gyttja, and peat with numerous organic remnants. The character of this series indicates that it was formed in a landlocked basin. Ten beds have been distinguished within the deposits.The depositional basin was alternately deepened or shallowed and periodically it was even covered with peat. A very important feature is the distribution of trace elements differing between the upper and the lower part of the profile. The lower deposits beds 1, 2, 3, 4, and 5) show marked Sr concentrations whereas V (with the exception of bed 1) is, entirely lacking. At the top of the series (beds 6, 7, 8, 9, 10) Sr is entirely lacking, whereas vanadium appears. Also the Cr content increases towards the top. The geochemical differences between the upper and lower part of the profile may serve as a basis for discussion on different provenance regions for the deposits studied.