Exotics-bearing layer in the Oligocene flysch of the Krosno Beds in the Fore-Dukla zone (Silesian Nappe, Outer Carpathians), Poland

A layer with exotic blocks has been found in the flysch of the Krosno Beds, in the Fore-Dukla Zone (the southernmost part of the Silesian Nappe in the Bieszczady Mts, Polish Outer Carpathians). It has been traced over a distance of 1 km near Wetlina (the Bieszczady Mts), in the southernmost exposed tectonic slice. The exotic blocks include crystalline schist (quartz-chlorite-muscovite-orthoclase schist with tourmaline and garnet) and three types of limestones: 1/ massive, sparitic, partly siliceous limestone, with numerous calcite veins; 2/ micritic limestone with rare planktic (Globigerina-like) foraminiferal tests; 3/ bioclastic limestone with numerous tests of small and large foraminifers, coralline algae (Rhodophyta), bivalves, bryozoans and rare echinoid spines. The exotics are embedded in light- and dark-grey argillaceous, partly sandy, calcareous matrix, together with a few small angular pebbles of grey mudstones and very fine-grained sandstones, which resemble lithological types of the Krosno Beds. The described rocks are similar to those found as exotic blocks in the Krosno Beds in neighbouring areas (Roztoki Dolne and Ustrzyki Górne) of the Central Carpathian Depression (Silesian Nappe). Calcareous nannoplankton from the exotic-bearing layer and neighbouring deposits show that they are not older than the NP24 Zone (late Kiscellian), below the isochronous marker horizon of the Jaslo Limestone. It may correspond to the Tenuitella munda Zone of Olszewska (1997, 1998), proposed for the Polish part of the Central Paratethys. The source area of the layer with exotics (islands with narrow shelf mafgins), probably lay to the south and south-east, was built mainly of crystalline rocks, and partly covered by various types of carbonate Eocene-Oligocene rocks. The deeper parts of the island slopes were covered with Cretaceous-Paleogene sediments, related to deep-water sedimentation in the marginal zone between the Dukla and Silesian subbasins. These deep-water deposits have been partly eroded during the submarine mass movements descending to the Silesian Subbasin

Maceral and calcareous nannofossil assemblages as proxies of late Rupelian (Oligocene) environmental changes in the Paratethys : an example from a section of the Menilite Formation in the northern Outer Carpathians

The Menilite Formation (Oligocene) of the Skole Nappe in the Polish Carpathians was deposited in the Paratethys. Deep-sea unbioturbated fine-grained carbonates of the Dynów Marl Member contain cold-water calcareous nannoplankton from Zone NP23 (Rupelian), including Reticulofenestra ornata and Pontosphaera fibula, which are typical of brackish waters in the Paratethys. It is likely that the water column was brackish in the upper part and fully marine and anoxic in the lower part. The Dynów Marl Member records the maximum isolation of the Paratethys from the oceanic circulation (the Upper Solenovian Event). The overlying green mudstones (probably the Krępak Member) are shallowly bioturbated. They contain fully marine, warm-water calcareous nannoplankton from Zone NP24. The environmental change (marine/brackish) is reflected in the quantity and type of organic matter. The abundance and preservation of organic matter are very high (TOC varies from 2.7 wt % to 26 wt %; HI values are >300 mg HC/g TOC) in brown, laminated shales, which were accumulated in saline anoxic conditions. The macerals in the shales are predominantly composed of the liptinite group, including lamalginite, telalginite, liptodetrinite, and bituminite. These macerals are primarily derived from planktonic and benthic algae as well as bacteria. The percentages of vitrinite and inertinite, originating from terrestrial sources, range up to 10% and 0.5%, respectively. The macerals are much less abundant in marls of the Dynów Marl Member because of dispersion in the carbonate groundmass during the calcareous nannoplankton blooms in brackish surface waters. The overall liptinite (mainly liptodetrinite and lamalginite) contribution is 77%–99.7%. Vitrinite and inertinite contents are in average 4.6% and 0.3%, respectively. Macerals are also infrequent in the overlying green mudstones, likely because of oxidation and consumption by organisms in warmer waters

Konkrecje syderytowe w warstwach paleoceńskich polskiej części wschodnich Karpat fliszowych

The present paper deals with the results of studies of siderite concretions occurring in black Paleocene shales of the Dukla and Silesian Units. The samples were examined using optical and scanning microscopy, X-ray diffraction and chemical analysis (SEM-EDS, INNA, ICP and estimation of TOC). The main diagenetic minerals of these concretions are iron carbonates close to siderite. Less common are dolomite, ferrous dolomite and calcite. The first phases precipitated from pore solutions were carbonates enriched in manganese. The concretions studied contain up to 49.15 wt.% $Fe_{2}O_{3}$, at most 16.46 wt.% CaO and up to 8.49 wt.% MgO, whereas the content of organic carbon (TOC) is at most 1.42 wt.%. Sideritic concretions of Paleocene beds of the eastern part of the Flysch Carpathians represent, in fact, sideroplesites and manganospherites of early diagenetic origin. They are, in general, impoverished in all trace elements, except Sr, when compared with shales embedding them. The siderite-bearing series in question can be assigned to the siderite-pyrite and siderite geochemical facies