Radiolarian biostratigraphy of the Upper Cenomanian-Lower Turonian deposits in the Subsilesian Nappe (Outer Western Carpathians)

The Upper Cenomanian-Lower Turonian flysch deposits of the Subsilesian Unit of the Outer Western Carpathians include a characteristic interval of green and black, siliceous shales with manganese concretions, benthonites and tuff, with abundant radiolarian fauna. Thirty two species of Radiolaria have been identified. Spherical cryptothoracic and cryptocephalic Nassellaria dominate in the assemblage. Two radiolarian species: Alievium superbum and Crucellacachensis have been proposed as biomarkers for setting the Cenomanian-Turonian boundary interval in the deposits ofthe Subsilesian series of the Polish Outer Carpathians

Radiolaria from the Upper Cenomanian-Lower Turonian deposits of the Silesian Unit (Polish Flysch Carpathians)

Upper Cenomanian to lower Turonian deposits of the Silesian Unit of the Polish Flysch Carpathians comprise a characteristic interval of green and black shales with manganese concrections, tuff and bentonites. These strata are not only distinctive lithologically, but also contain a rich radiolarian fauna. Thirty-five species of Radiolaria have been identified. Spherical cryptothoracic and cryptocephalic Nassellaria dominate in the assemblage, especially species such as Holocryptocanium barbui, H. tuberculatum, Hemicryptocapsa prepolyhedra and H. polyhedra. The systematic description of fifteen species belonging to order Spumellaria and twenty species of Nassellaria is presented herein

Mid-Cretaceous spicule-rich turbidites in the Silesian Nappe of the Polish Outer Carpathians : radiolarian and foraminiferal biostratigraphy

Spicule-rich turbidites are widespread inmid-Cretaceous deep-water flysch of the Subsilesian and Silesian units in the Polish Outer Carpathians. The spicule-rich material with an admixture of numerous radiolarian and foraminiferal particles was supplied, together with siliciclastic material, from shallow environments, mostly from the northern margin of the Carpathian Basin. We present new data on theage of these deposits in the Silesian Nappe, where they are distinguished as the Mikuszowice Cherts. This unit is composed of medium-and thick-bedded siliciclastic to calcareous turbidites including bluish cherts in their middle and upper parts and of thin non-calcareoushemipelagic shales. We have studied radiolaria and foraminifera from hemipelagic sediments and spicule-rich turbidites, from two con-tinuous sections in the Barnasiówka Range (Beskid Wyspowy Mts.) that included the Mikuszowice Cherts (31 m thick) and their transition into the surrounding units. The age of the Mikuszowice Cherts was determined taking into account the following radiolarian datumevents: (1) the occurrence of Praeconocaryomma lipmanaein the entire unit, (2) the FO (first occurrence) of Hemicryptocapsa tuberosain the upper part of the unit, (3) the FO of Amphipyndax stockiclose to the upper boundary of the unit, (4) the FO of Hemicryptocapsa prepolyhedra in the lowermost part of the overlying Barnasiówka Radiolarian Shale Formation. These datum events appear successivelyin the Western Tethys successions within the Rotalipora cushmani planktonic foraminiferal Zone, which corresponds to the middle andupper Cenomanian (except for its uppermost part). The foraminiferal assemblages, in which such taxa as Rotalipora cf.cushmani, R. cf. greenhornensis, whiteinellids and Uvigerinammina praejankoi successively appear, confirm the mid-late Cenomanian age of thespicule-rich turbidites in the Silesian Nappe

Evidence of bacteriogenic iron and manganese oxyhydroxides in Albian-Cenomanian marine sediments of the Carpathian realm (Poland)

The Albian and Cenomanian marine sediments of the Silesian and Tatric basins in the Carpathian realm of the Western Tethys contain ferric and ferromanganese oxyhydroxides, visible macroscopically as brown stainings. They coat calcareous bioclasts and mineral clasts, fill pore spaces, or locally form continuous, parallel microlayers, tens of micrometers thick. Light-microscope (LM) and scanning-electron-microscope (SEM) obser- vations show that the coatings contain elongated capsules, approximately 3-5 \mum across and enriched in iron and manganese, which may be remnants of the original sheaths of iron-related bacteria (IRB). Moreover, the ferric and ferromanganese staining observed under LM is similar to bacterial structures, resembling the sheaths, filaments and rods formed by present-day bacteria of the Sphaerotilus-Leptothrix group. All of the possible bacteria-like structures are well preserved owing to processes of early diagenetic cementation. If the observed structures are fossil IRB, these organisms could have played an important role in iron and manganese accumulation on the sea floor during Albian-Cenomanian time. The most plausible source of metals for bacterial concentration in the Silesian Basin might have been submarine low-temperature hydrothermal vents, as previously was hypothesized for Cenomanian-Turonian deposits on the basis of geochemical indices

Pyritized radiolarians from the Mid-Cretaceous deposits of the Pieniny Klippen Belt : a model of pyritization in an anoxic environment

Excellently preserved, pyritized radiolarian skeletons have been found within the Upper Cenomanian deposits in the Pieniny Klippen Belt (PKB-Carpathians, Poland). On the basis of a study of their chemical composition, structure of replacing skeletons and exceptional preservation of all morphological details, we propose a new model where the pyritization process took place not in sediment but while the radiolarian skeletons were suspended in the anoxic water column. The radiolarians rich in organic matter, sinking through the upper (iron rich) part of an anoxic water column, became the sites of organic matter decomposition and enhanced bacterial sulphate reduction. Dissolved iron in this zone diffused into the radiolarians and precipitated as iron sulphides replacing the opaline skeletons. This process was controlled by the rates of opal dissolution and of bacterial sulphate reduction, and the availability of dissolved iron. The preservation of radiolarians in the Upper Cenomanian deposits from different depth sub basins of the PKB was compared. We found that the extent of pyritization and preservation of radiolarian skeletons may be dependent on the depth of the basin and the position of the oxic-anoxic interface

Multivariate discrimination of Buryella species from the Lower Eocene of the Outer Flysch Carpathians, Poland

Variegated shales in the Lower Eocene hemipelagic deposits of the Subsilesian Series, Polish part of the Western Carpathians, have yielded rich radiolarians with common representatives of the genus Buryella. Two new radiolarian species, Buryella spina sp. nov. and Buryella hannae sp. nov., are described, and two other species have been recognized: Buryella tetradica Foreman and Buryella clinata Foreman. Specimens have been measured, grouped and interpreted using cluster analysis, principal component analysis (PCA) and canonical variates analysis (CVA). Species attributed to Buryella have three or four segments, a fusiform or lobate outline, and a constricted, rather than flared, aperture. The cephalis always possesses an apical horn of varying length with a distinct vertical pore at the collar stricture. All specimens possess a pronounced vertical tube, rounded or elongate, that might extend to the base of apical horn. Near the base of the cephalis the parallel ridges observed on the external wall of the cephalis are ridges from the horn that diverge and extend to the collar stricture except ventrally, where two ridges rejoin to enclose the vertical pore and form an upwardly directed tube. These structure might be evidence of the presence of arches (A-Vbl, A-Vbr) and bars (Vbl, Vbr), which form the vertical tube

Successive stages of calcitization and silicification of Cenomanian spicule-bearing turbidites based on microfacies analysis, Polish Outer Carpathians

Mid-Cretaceous turbidites with large proportions of sponge spicules are widely distributed in the Silesian Nappe of the Outer Carpathians, giving rise to diversified types of sediments, from spiculites to spicule-bearing siliciclastics and calcarenites. Part of this succession, Middle–Late Cenomanian in age, was transformed into cherts. A microfacies study showed that these turbidite sediments underwent several stages of calcitization and silicification, which took place during Mid-Cretaceous times in different sedimentary environments, i.e., on a northern shelf bordering the Silesian Basin and on a deep sea floor. The first diagenetic changes were related to changes to the biotic components of the turbidite layers, dominated by siliceous sponge spicules. This process, which took place in the spiculitic carbonate mud on the shelves, was related to the calcitization of sponge spicules. Calcareous clasts and calcified skeletal elements also were corroded by bacteria. After transportation down the slope, the biogenic and siliciclastic particles were deposited below the carbonate compensation depth. Taphonomic processes on the basin floor and alternating phases of carbonate and silica cementations, recrystallization and dissolution occurred in these sediments and were related to the diversification in composition of successive turbidite layers. Silicification was related to the formation of quartz precipitates as fibrous chalcedony or microcrystalline quartz, which were derived from the earlier dissolution of amorphous silica, originating mostly from siliceous sponge spicules and radiolarian skeletons. However, a source of silica from hydrothermal vents was also possible. The initial silica precipitation could have taken place in a slightly acidic environment, where calcite was simultaneously dissolved. A number of silicification stages, visible as different forms of silica precipitate inside moulds after bioclasts, occur in the particular turbidite layers. They were related to changes in various elements of the pore-water profile after descending turbidity-current flows. A very low sedimentation rate during the Middle–Late Cenomanian in the Silesian Basin may have favoured the sequence of initial calcitization and silicification stages of the turbidite sediments

Stromboli – the best place to actively learn and understand the behavior of an active volcano and its processes // Stromboli – najlepsze miejsce do poznania aktywnego wulkanu i zrozumienia procesów wulkanicznych

Basaltic volcanism, a dominant mode of volcanic activity on Earth, occurs as explosive eruptions, resulting from the exsolution of magmatic gases and is exhibited by Strombolian and Hawaiian types. Strombolian activity takes its name from frequent, small-scale explosions of the Stromboli Volcano, which was formed within the Aeolian Islands, north of Sicily. This paperpresents the volcanic structure and features of its activity, based on the results of numerous studies carried out during the last 15 years. In the intention of the authors, this educational presentation would be an incentive to make a decision to travel to Stromboli and see its present-day activity and its effects from just a few hundred meters. To have a safe experience and to avoid accidents and injuries, the tourists need to have sufficient up-to-date information, before they embark on their adventure.//Wulkanizm bazaltowy (dominujący typ aktywności wulkanicznej na Ziemi), który jest związany z ekshalacją gazów pomagmowych, ma charakter eksplozywnych erupcji określanych mianem typu hawajskiego i strombolijskiego. Aktywność strombolijską charakteryzują częste, niewielkiej objętości wybuchy, które występują m.in. na czynnym wulkanie Stromboli, znajdującym się w łuku Wysp Liparyjskich (Eolskich), na północ od Sycylii. W artykule przedstawiono budowę wulkanu, jego działalność i przyczyny tej działalności na podstawie wyników licznych badań, przeprowadzonych w ciągu ostatnich 15 lat. W intencji autorów przedstawione w sposób możliwie prosty informacje, zdjęcia i ryciny tego wulkanu mają być materiałem edukacyjnym i jednocześnie zachętą do podjęcia decyzji o podróży, żeby z odległości kilkuset metrów móc samemu zobaczyć erupcje wulkaniczne. Aby poznawanie wulkanu było bezpieczne, turyści powinni zapoznać się z aktualnymi informacjami o warunkach panujących na ścieżkach turystycznych