This paper aims to characterize and interpret the trends in reserves, resources, and mine production of diatomite in the Czech Republic in last two decades. With more than 2.4 million tonnes of total reserves, 1.6 million tonnes of exploitable (recoverable) reserves, and average annual production of 35 kt, diatomite is not one of the key industrial minerals of the Czech Republic, which ranks among the top 10 European producers. Historical diatomite deposits were situated within the Cheb Basin, where the Holocene Hájek diatomite deposit was abandoned in 1955 because of the establishment of the Soos National Natural Monument. The group of Tertiary diatomite deposits situated in the Central Bohemian Upland ceased extraction when the last deposit (Kučlín) was abandoned in 1966 after depletion of reserves. The last group of diatomite deposits is located within the Southern Bohemian basins, where the last productive deposit, Borovany-Ledenice, is situated. Miocene diatomites are extracted by open pit mining there. Production of crude diatomite varied from 0 to 83 kt, with an average of 35 kt, between 1999 and 2018 according to stockpiles. Raw diatomite is classified into two groups according to the chemical-technological properties. Better-quality diatomite (SiO2 ≥ 72%, Al2O3 ≤ 15%, Fe2O3 < 2.4%, bulk density 450 kg/m3, loss on ignition < 8%) is processed for filtration in the food industry (brewery, wine, and raw fruit juices). Material with lower quality is used in combination with bentonite to prepare cat litter products.

This paper presents geochemical data for 171 core samples of the Carboniferous coal-bearing series and the Miocene cove from the central part of the Upper Silesian Coal Basin. Major oxide concentrations (Al ₂O ₃, SiO ₂, Fe ₂O ₃, P ₂O ₅, K ₂O, MgO, CaO, Na ₂O, K ₂O, MnO, TiO ₂, and Cr ₂O ₃) were obtained using XRF. Trace and major elements (Mo, Cu, Pb, Zn, Ni, Co, U, Cr, V, Mn, As, Th, Sr, Cd, Sb, Bi, Ba, Ti, W, Zr, Ce, Nb, Ta, Be Sc) were analysed ICP-MS. The main goals of this study were to demonstrate the distribution, as well as the stratigraphical variability, of the selected elements and to determine whether chemostratigraphy tools could be effectively applied to analyze Carboniferous and Miocene deposits of the USCB. Geochemical studies have shown showed different geochemical features of the samples from the Carboniferous and the Miocene. The diversity is mainly expressed in the enrichment of Miocene sediments in Ca and Sr related to biogenic carbonate material. It was also stated that the concentrations of trace elements associated with the detrital fraction, such as Zn, Cr, Co, Ba, Ti, Zr, Nb, and Sc show slightly higher values in Carboniferous sediments. On the basis of the content of Ti, Zr, and Nb, as well as ratios such as Th/U, Zr/Th, Ti/Zr, and TiO ₂/K ₂O, units with different inputs of the terrigenous fraction can be identified in both Carboniferous and Miocene formations. The paper shows that chemostratigraphy can be used as a stratigraphic and correlation tool for the Carboniferous and the Miocene deposits of the USCB.

The paper presents new data on the Miocene development within the Upper Silesian Coal Basin. The Miocene succession of the study area is characterized by high thickness and highly variable lithology. In the Miocene sediments of the studied area, the presence of organic matter in the form of a coal layer, coal crumbs, and dispersed organic matter has been found. The research focused mainly on the analysis of organic matter in terms of its origin, degree of coalification, and depositional environment. The degree of coalification of organic matter was determined by the huminite/vitrinite reflectance. The hard brown coal layer with a thickness of about eight meters was identified within the Kłodnica Formation. Based on the textural properties and degree of coalification, brown coal was classified as dull brown coal and bright brown coal. Organic matter in the form of coal crumbs and dispersed organic matter were found within a package clastic sedimentary. On the basis of petrographic analysis, two types of allochthonous organic matter with different degrees of coalification were identified. The coal clasts are mainly of Carboniferous origin, while the Miocene redeposited brown coal grains dominate within the dispersed organic matter. Coal fragments and dispersed organic matter derived from the Miocene brown coal were also found within the black claystones. The study of organic matter of the Miocene sediments in the Upper Silesian Coal Basin showed both its autochthonous and allochthonous origins.

The algal microfossil Bolboforma reticulata Daniels and Spiegler is recorded from the Oligocene-Miocene glacio-marine sediments of King George Island, South Shetland Islands, Antarctica. The record extends the geographic extent of the species to Antarctica.

Remains of decapod crustaceans of the family Alpheidae Rafinesque, 1815 and bony fish of the family Gobiidae Bonaparte, 1832 co-occur at a number of localities in the Korytnica Basin (Holy Cross Mountains) and in a newly exposed section along a stream near Niskowa (Outer Carpathians), both in southern Poland. These remains (alpheid major right-sided cheliped tips and gobiid otoliths) are interpreted as documenting a commensal partnership that existed in the shallowest zones of the middle Miocene Fore-Carpathian Basin in southern Poland under environmental conditions that must have been comparable to those of the present-day tropical/ subtropical Indo-West Pacific and Caribbean.

Cephalopod specimens assigned to the Argonautidae (Obinautilus pulchra Kobayashi, 1954 and an unknown taxon) from two localities of the Mishan Formation in Gohreh and Khorgu sections, Bandar Abbas, southern Iran, are reported for the first time from the Persian Gulf area. The co-existing foraminifera confirm the middle Miocene age of the strata. Based on micropalaeontological data, the previous Oligocene age of Obinautilus pulchra is extended to the middle Miocene. The palaeobiogeographic distribution of the reported Argonautidae shows that the presence of these faunas is limited to the West Pacific, Indo-Pacific and the East Pacific. The present-day distribution of the Argonautidae is similar to the ancient one and seems to be inherited from their ancestors.

Upper Miocene (~6 Ma) sediments from a north-south transect of Ocean Drilling Program Holes 848B, 849B, 850B, 851B across the equator in the Eastern Pacific Ocean record an episode of unusual skeletal variability associated with the silicoflagellate Bachmannocena diodon subsp. nodosa (Bukry) Bukry, 1987. Skeletons in this plexus persisted for between 55,000 and 75,000 years and include an arch across a 2-sided basal ring, a highly unusual morphology for the genus. Groups of skeletal morphotypes were common within the plexus episode, and occur in a systematic sequence that is consistent between sites. As a result of this study, silicoflagellates previously placed in the genus Neonaviculopsis Locker and Martini, 1986 are now considered part of the Bachmannocena diodon subsp. nodosa plexus.

A new species of heterobranch gastropods, the hammerhead Chelidonura radwanskii sp. nov., found in the socalled Pleurotoma-clays of middle Miocene (Langhian) age in the environs of Korytnica, southern Holy Cross Mountains, Poland, is described. It is the first fossil representative of Chelidonura A. Adams, 1850. This tiny gastropod is named in honour of the late Professor Andrzej Radwański.

The decapod fauna from the Badenian (middle Miocene) deposits of western Ukraine comprises in total 31 taxa: 20 species, 9 taxa left in open nomenclature, and 2 determined at family level. Thirteen of these taxa are reported for the first time from the territory of Ukraine. Among them are the first records of Trapezia glaessneri Müller, 1976 in the Fore-Carpathian Basin and Pachycheles sp. in Paratethys. One taxon (Petrolisthes sp. A) probably represents a new species. The occurrence of this significant decapod fauna is restricted almost exclusively to the Upper Badenian (i.e., early Serravallian) coralgal reefs of the Ternopil Beds. The taxonomic composition of the decapods indicates that the Late Badenian depositional environment was a shallow marine basin dominated by reefs that developed in warm-to-tropical waters of oceanic salinity. The decapod assemblage from the Ternopil Beds is similar in its taxonomic composition to numerous decapod faunules from fossil reefs of Eocene to Miocene age from the Mediterranean realm and of Miocene age from Paratethys. In contrast, decapod remains are very scarce in Badenian siliciclastic deposits (Mikolaiv Beds) and are represented by the most resistant skeletal elements, i.e., dactyli and fixed fingers. This scarcity was caused by the high-energy environment, with frequent episodes of redeposition, which disintegrated and abraded the decapod remains.

Many geological problems have not been convincingly explained so far and are debatable, for instance the origin and changes of the Neogene depositional environments in central Poland. Therefore, these changes have been reconstructed in terms of global to local tectonic and climatic fluctuations. The examined Neogene deposits are divided into a sub-lignite unit (Koźmin Formation), a lignite-bearing unit (Grey Clays Member), and a supra-lignite unit (Wielkopolska Member). The two lithostratigraphic members constitute the Poznań Formation. The results of facies analysis show that the Koźmin Formation was deposited by relatively high-gradient and well-drained braided rivers. Most likely, they encompassed widespread alluvial plains. In the case of the Grey Clays Member, the type of river in close proximity to which the mid-Miocene low-lying mires existed and then were transformed into the first Mid-Miocene Lignite Seam (MPLS-1), has not been resolved. The obtained results confirm the formation of the Wielkopolska Member by low-gradient, but mostly well-drained anastomosing or anastomosing-to-meandering rivers. The depositional evolution of the examined successions depended on tectonic and climatic changes that may be closely related to the mid-Miocene great tectonic remodelling of the Alpine-Carpathian orogen. This resulted in palaeogeographic changes in its foreland in the form of limiting the flow of wet air and water masses from the south and vertical tectonic movements.

Over three thousand specimens representing the superfamily Trochoidea Rafinesque, 1815 [Trochidae Rafinesque, 1815 and Calliostomatidae Thiele, 1924 (1847)] from the upper Upper Badenian = Kosovian = lower Serravallian (middle Miocene) marine deposits of Ukraine, housed in the collections of the Polish Academy of Sciences Museum of the Earth in Warsaw (MZ), are studied herein. The abundant material has allowed for investigations of the intraspecific variation and revision of earlier determinations. As a result, 21 species belonging to 5 genera have been identified, described and illustrated, of which one is new [Clanculus (Clanculopsis) krachi sp. nov.] and one is left in open nomenclature. Granulifera O. Anistratenko, 2000 is considered a junior subjective synonym of Clanculopsis Monterosato, 1879; Granulifera pulla O. Anistratenko, 2000 is considered a junior subjective synonym of Monodonta tuberculata Eichwald, 1830; Gibbula sytovae Amitrov, 1961 is considered a junior subjective synonym of Trochus miocaenicus Mayer, 1853; Gibbula volhynica Friedberg, 1928 is considered a junior subjective synonym of Trochus novemcinctus von Buch, 1830; and Trochus buchii du Bois de Montpéreux, 1831 is suppressed in favour of the senior subjective synonym Trochus puschii Andrzejowski, 1830. The geographic distribution and stratigraphic ranges of the taxa are given. Six species are known only from the Polish-Ukrainian part of the Fore-Carpathian Basin. The protoconch features are systematically studied in the Trochidae and Calliostomatidae from this area for the first time.

The well-known Pleuronectia badensis Fontannes, 1882 (currently classified as Cristatopecten cristatus badense) is declared as a n omen protectum against the older synonym Pecten burdigalensis var. polonica Pusch, 1837 considered a nomen oblitum. It ranges from the early to the late Miocene (Burdigalian–Messinian) of the NE Atlantic and Mediterranean. In the Central Paratethys it appeared in the early Miocene (Karpatian, correlating with the latest Burdigalian) and became extinct in the middle Miocene (Late Badenian, correlating with the early Serravallian). In Poland – the northernmost part of Central Paratethys – the occurrence of this taxon is limited to the late Early Badenian (late Langhian).

Brachiopods are reported for the first time from the Lower Miocene Cape Melville Formation of King George Island, South Shetland Islands, West Antarctica. Two genera, Liothyrella Thomson and Paraldingia Richardson have been identified. This is the first occurrence of Paraldingia in Antarctica.

The subject of the research was the Middle Miocene red algal limestone from the Włochy deposit, which is currently the only place of exploitation of the Pińczów Limestone representing a local type of the Leitha Limestone. The collected samples of this rock belong to the organodetric facies of diverse grain size and sorting of clastic material. Considering the proportions of characteristic skeleton remains, the composition of the coarse-grained organodetric facies is red algal-foraminiferalbryozoic, while of the fine-grained facies is foraminiferal-red algal. The cement of these rocks is predominantly sparite compared to micrite-clay matrix. A complement to petrographic studies was the chemical analysis and identification of mineral phases with X-ray diffraction. Moreover, physical and mechanical properties of samples were analyzed. Porosity of the rock was assessed in the polarizing and scanning microscope (SEM-EDS) observations, as well as with a porosimetric tests. The coarse-detrital limestone with a dominant binder in the form of intergranular cement is characterized by the apparent density sometimes exceeded 1.90 Mg/m3, while fine-grained limestone has the highest water absorbability (above 20%) and total porosity (about 40%). The above properties influenced high water absorption by capillarity, limiting the possibility of using limestone in places exposed to moisture. The observed relationship between the ultrasonic waves velocity and the uniaxial compressive strength gives the possibility of predicting the value of the latter parameter in the future. The limestones from Włochy deposit do not differ in quality from the previously used Pińczów Limestones, and their technical parameters predestine them for use as cladding material with insulating properties.

For the first time, articulated shells of Anomia ephippium Linnæus, 1758, the bivalve species widely distributed in the Egerian–Late Badenian (latest early Oligocene to late middle Miocene) in the Central Paratethys, are described and illustrated. The most astonishing fact is the presence of a heavily calcified byssus that anchored the animal to hard substrates, which is still preserved inside the byssal notch. The investigated material derives from the Badenian (middle Miocene) Niskowa Formation in the Nowy Sącz Basin, a small intramontane basin situated in the Polish Outer Carpathians. Apart from articulated shells and left valves, the collected material contains some dozen of calcified byssi fixed to rigid substrate, SEM images of which are presented. Examination of the A. ephippium specimens stored in the Polish Academy of Sciences, Museum of the Earth in Warsaw revealed other Paratethyan records of anomiid calcified byssi attached to other specimens of A. ephippium. Finally, the paper provides an overview of the previous studies on the representatives of the genus Anomia Linnæus, 1758 from the Central Paratethys and its specific assignment.

The results of drill stem tests made on the autochthonous Miocene deposits of the Upper Badenian - Lower Sarmatian age in the Carpathian Foredeep were analyzed. Reservoir tests were performed in open and cased holes, where inflows of formation water of varying saturation degree and sometimes contaminated with drilling mud filtrate, were observed. A total of 58 intervals, geophysically qualified as gas-bearing, were analyzed. Statistical analysis methods were used for determining the influence of the formation depth on the depth of deposition of the Miocene, and also dependence of initial back-pressure exerted on the reservoir during DST, on the depth of deposition of the reservoir. No correlation was found between water flow rate and initial differential pressure. A satisfactory correlation was obtained between hydrostatic pressure of water cushion in the tubing string and reservoir pressure for selected 22 the Miocene intervals in the Dębica region. In this region the pressure quotient php/pz broadly ranged between 0.05 and 0.57. Another correlation was noted between initial back-pressure and a depth at which pressure was measured and initial back-pressure, and formation water flow rate. The regression equations determined with statistical methods can be used for predicting values of formation pressure, initial value of back-pressure, formation water flow rate and initial differential pressure during DST. On this basis technological parameters of successive reservoir tests can be determined for in the analyzed area of the Carpathian Foredeep, particularly in the Dębica region.

Echinoids represent an important component of the Cenozoic marine benthic communities. Their diversity in the Mediterranean area is reviewed within the Late Miocene–Recent, a period of remarkable paleogeographic and paleo- climate changes. Of the 37 genera that lived during the Late Miocene, only Holaster, Pliolampas, and Trachyaster did not survive the Messinian Mediterranean salinity crisis (MSC), indicating that this event was not as drastic as for other marine groups. The presence of Brissopsis within the uppermost Messinian testifies to the existence of fully marine conditions at least towards the end of the MSC. Severe drops in the echinoid diversity, involving the loss of 40% of the Pliocene genera, occurred during the Piacenzian, likely because of the onset of the Northern Hemisphere glaciation. Most of the echinoid extinctions correlate with the crisis of the Mediterranean bivalve assemblage recorded at about 3 Ma. The Early Pleistocene progressive cooling caused the disappearance of further thermophilous shallow-water genera (Clypeaster, Schizechinus, Echinolampas) and allowed the entrance of temperate taxa ( Paracentrotus lividus, Placentinechinus davolii and Sphaerechinus granularis) from the Atlantic. Some deep-water taxa ( Histocidaris sicula, Stirechinus scillae, Cidaris margaritifera), whose Recent relatives are currently restricted to tropical areas, are not found in the area after the Calabrian possibly because of the disappearance of the psychrosphere. The extant Mediterranean echinoid fauna mainly derives from the Late Miocene fauna, reduced after several climatic changes by about 43% at the genus level. The recent increase of the sea surface temperatures allowed the entrance of the Lessepsian Diadema seto sum and confined the deep-water species of Holanthus to the coldest areas of the basin, making this genus endangered.

Trace fossils Phymatoderma melvillensis isp. nov., Thalassinoides isp., ?Nereites isp. and Planolites isp. are reported from the glacio−marine sediments of the Cape Melville Formation (Lower Miocene) of King George Island, West Antarctica. Their occurrence and strong bioturbation of sediments point to an offshore or deeper (outer shelf or upper slope) en− vironment. Deep marine crab Antarctidromia inflata Förster, 1985, has been found in Thalassinoides isp. The tracemaker (?crustacean) of Phymatodermamelvillensis re−reworked pelletal sediments probably during times of food deficiency.

In this study some of the experimental results of water shut-off treatments in oil and gas production wells were presented. The effect of water saturation of Miocene rocks of the Carpathian Foredeep on the relative permeability to gas was analyzed. Also, wide review of the worldwide publications from the point of view of the results obtained in water shut-off treatments in oil and gas formation was presented. Based on experimental results efficiency of relative permeability modification of sandstone from Szydłowiec to brine and nitrogen by four selected chemicals polymers and microgels was evaluated. Experimental results indicated that trend changes of permeability modification strongly depends on the fluid used in the RPM treatment. Moreover, efficiency of permeability modification to brine depends on flow rate of brine through the core - the lower brine flow rate the higher efficiency of the RPM treatment. RPM product number 1 caused significant loss of permeability to brine ca. 60% and slight permeability modification to gas ca. 18%. This permeability change to brine and gas was obtained by modification of formation wettability what affects well productivity. In the case of product number 2 which is based on microgels technology, also significant modification of selective permeability to brine was observed. Loss of permeability to brine was in the range of 65 to 90% while to gas ca. 50%.