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Abstract

The radiolarian biostratigraphy of the Middle–Upper Jurassic pelagic siliceous sediments (Czajakowa Radiolarite Formation) in the Niedzica succession of the Pieniny Klippen Belt (Carpathians) is interpreted in terms of their age in a stratotype section, and facies equivalents in other tectonic-facies units of this region. The siliceous sediments are represented by radiolarian cherts and silicified limestones which are underlain and overlain by red nodular limestones, equivalents of the Rosso Ammonitico facies. The radiolarian association includes thirty-seven taxa belonging to twenty one genera which represent the Northern Tethyan Palaeogeographic Province. Key radiolarians recorded provide a means of correlation with zonation schemes based on Unitary Associations defined for the Jurassic Tethyan sediments. The age of the Czajakowa Radiolarite Formation in the stratotype section is determined as U.A.Z.9 to U.A.Z.11 corresponding to middle Oxfordian up to Kimmeridgian. Comparison of radiolarian biozones from the stratotype section with other facial equivalent sections in the Pieniny Klippen Belt reveals a significant diachronism for both the lower and the upper limits of the Jurassic pelagic siliceous facies.
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Abstract

The aim of the study was to evaluate the degree of pollution of bottom sediments from small water reservoirs with heavy metals on the basis of geochemical criteria: the enrichment factor and the geo-accumulation index. The investigations concerned sediment from eight small water reservoirs located in the Kielce Highland. Selected heavy metals, including cadmium, chromium, copper, lead and zinc, were determined using inductively coupled plasma-atomic emission spectrometry method. Additionally, particle size distribution and the content of organic matter expressed as loss of ignition were designated. The concentration of heavy metals in sediments was characterized by a great variety. The sediments of Morawica and Rejów show very high and extremely high enrichment in Cr, Zn, Pb and Cd. The values of EF>20 indicate also an extremely high enrichment in Cd of sediments in Mostki. In addition, over 50% of the samples of sediment from Suchedniów, Kaniów, Mostki and Jaśle reservoirs (the value of EF for Cr exceeded 5) indicate a moderately high enrichment of this element. Results of the analysis of the Igeo values indicate that the tested sediments are characterized by moderately high (2<Igeo<3) or high (3<Igeo<4) pollution. The differences in individual enrichment factor and geoaccumulation index values may result in the nature of heavy metals, their pollution loads, as well as speciation forms of trace elements occurrence in sediment-water complex. These findings indicate that the integration of geochemical methods is necessary for an appropriate ecological risk assessment of heavy metals in bottom sediments.
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