Search Results (14)

An exposed sedimentary succession, ca 115 m of a total of 1000 m, from the Eastern Carpathian foredeep was, for the first time, analyzed using facies analysis and scale- and time-independent sequence stratigraphy methods to reveal the depositional environment and its cyclic sedimentation. The outcropping deposits, belonging to the Șomuz Formation, dated on the basis of molluscs, foraminifera, and ostracods, are uppermost Volhynian (upper Serravalian). The three recurrent facies associations we have distinguished indicate a storm-dominated shoreface–offshore transition environment. Five-decametre-thick high-frequency sequences (HFS1–5), at most of 4th order, bounded by maximum regressive surfaces, were defined in the studied interval. The maximum thickness of the Volhynian deposits in the area, known both from well sites and outcrops, allowed us to estimate the sedimentation rate at ca 1.5 m/kyr. The fossil content shows that the entire sedimentary succession was deposited in very shallow to shallow water during the whole Volhynian (12.65 - ca 12.01 Ma). The time interval we studied was estimated at ca 75 kyr, so the average time of one HFS is ca 15 kyr. At this scale, considering that both high subsidence and Eastern Paratethys sea-level rise added to accommodation, the sediment supply must have been the main control of cyclic sedimentation, which, in turn, must have been controlled by precession climatic changes in the source area. The estimated time of an HFS is shorter than a precession cycle, but better dating might support or refute this hypothesis. This paper may awaken the interest of the owners of better data, especially from subsurface (seismic, well logs), to complete the data from natural exposures. Full article

Coprolites from the Oligocene Menilite Formation of the Outer Carpathians in southeastern Poland were investigated to reveal the diversity of prey fishes consumed by coprolite producers. The material comprises 186 coprolites from seven localities. The coprolites are either sub-spherical, or elongate, and although classified into eight shape categories, display a morphological continuum. The phosphatic matrix is preserved in 28% of the specimens. Fish remains, including bones and scales, are preserved in 94% of the coprolite specimens. In 31% of specimens, these remains belong to the orders Perciformes, Gadiformes, Clupeiformes, and Aulopiformes. Prey sizes were estimated and compared to the sizes of fishes preserved as articulated skeletons from the same formation, that inhabited the Carpathian Basin of the Paratethys. The results demonstrate that coprolite analysis provides a significant paleontological data, which can be applied to infer fish diversity in other regions of the Paratethys, as well as in other sedimentary basins. Full article

A new species of the genus Niphargus Schiödte, 1849 (Crustacea: Amphipoda: Niphargidae), co-existing with other stygobiotic amphipods, Diasynurella kiwi Marin and Palatov, 2023 and Pontonyx donensis (Martynov, 1919) (Crangonyctidae), is described from a small spring on a shore of Kiziterinka River in Rostov-on-Don City in the mouth of the Don River. Two of the three species in the studied spring, D. kiwi and the discovered Niphargus, belong to microcrustaceans not exceeding the total body size of 3 mm. The new species, Niphargus rostovi sp. nov., represents one of the smallest species within the genus and is mostly related to the Greek Niphargus karkabounasi Ntakis, Anastasiadou, Zakšek and Fišer, 2015, which is also not reaching the body size of 3 mm. One more related undescribed species is found on the Crete Island by the molecular genetic data. These species represent a separate phylogenetic lineage within the “carpathicus” species complex, which diverged from the congeners in the Late Miocene for more than 10 Mya. At the same time, the speciation within the ingroup started about 5–6 Mya, obviously correlating with the drainage of the Euxinian basin of the Eastern Paratethys, connecting the lower Don and southern Greece areas. Niphargus potamophilus Birštein, 1954 is also first recorded from the mouth of the Belbek River in the Crimean Peninsula, closing the known area from the Kuban River delta to Rostov-on-Don area and further along the western coast of the Black Sea to Bulgaria. Analysis of the recent records of long-time lineages of endemic/subterranean/stygobiotic animals unable to disperse for long distances assumed that glacial refugium existed at the mouth of the Don River, along with the South Caucasus (Colchis) and the southern Caspian (Hyrcania), where many species have survived several periods of glaciation since the late Miocene. Full article

The pulmonate gastropod genus Ellobium has its greatest diversity in the modern Indo-West Pacific Region (IWP). Its origin, however, is traced to the Early Oligocene of the Northeastern Atlantic and the Western Tethys Region. Two Ellobium species are documented from the Rupelian of France and Italy and a new species is recorded from the Chattian of Hungary: Ellobium kerwaensis nov. sp. The first records in the IWP are known from the Early Miocene, suggesting an eastward range expansion of the genus around the Oligocene/Miocene boundary, when Ellobium became extinct in the European seas. Extant Ellobium species are bound to habitats above the high tide line in salt marshes and mangroves. Comparable environmental requirements are expected for the fossil congeners. Ellobium may derive from Eocene ancestors, such as the Bartonian Eoellobium heberti from the Northeastern Atlantic. Eoellobium is introduced in this paper as a new genus. Full article

A new species of the genus Niphargus Schiödte, 1849 (Crustacea: Amphipoda), co-occurring with water louse Asellus cf. aquaticus (Linnaeus, 1758) (Crustacea: Isopoda) in deep wells, is described from the Tarkhankut Upland, located in the northwestern part of the Crimean Peninsula. Niphargus tarkhankuticus sp. nov. corresponds to a separate phylogenetic lineage (the “tarkhankuticus” ingroup), also including several undescribed species from the coastal habitats of the Black Sea (the Crimean Peninsula, the southern Caucasus and the northern coast of Turkey), which is related to the paraphyletic European “stygius-longicaudatus” group. The divergence of the “tarkhankuticus” ingroup from the related European species probably appeared in the Late Miocene age, about 11–10 Mya, related to the separation of the Eastern Paratethys for different basins (Euxinian, Alpine and Pannopian). At the same time, the speciation within the ingroup started in Pliocene, about 5.76–3.6 Mya, and correlated with the Black Sea leveling and the drainage of coastal marine carbonate accumulations, including the Tarkhankut Upland. Intraspecific values of COI mtDNA gene markers (p-distances) for N. tarkhankuticus sp. nov. are about 2%, showing that the division into a number of isolated subpopulations, probably associated with local tectonic movements, the active formation of the river network, and further karst processes in the Tarkhankut Upland occurred during the Pleistocene (since 2.58 Mya). Analysis of stable isotopes (δ¹³C/δ¹⁵N) revealed that only discovered macrocrustaceans in the studied wells of the Tarkhankut Upland have non-overlapping trophic niches, with A. cf. aquaticus possibly feeding on algae/periphyton, while the trophic position of N. tarkhankuticus sp. nov. is close to predators. Full article

A total of 205 COI sequences and 310 cyt b sequences of the threespine stickleback (Gasterosteus aculeatus) from basins of all seas throughout the vast range of this species were analyzed. Median networks of haplotypes constructed in this study, combined with the results of reconstruction of paleogeographic conditions, led to the conclusion that the threespine stickleback emerged as a species in the Pacific Ocean basin and spread to Europe from the south, populating the system of water bodies that existed in the Oligocene. The main water body was the Paratethys Ocean (Sea), which existed 5–34 Mya. In the area of the modern North Sea, stickleback populations, part of which later migrated to the eastern and western coasts of North America, gave rise to the group of haplotypes that has the widest distribution in northern Europe. The stickleback populations belonging to the lineage that dispersed along the Arctic and western coasts of North America displaced the carriers of the haplotypes of the ancient phylogenetic lineage that inhabited the Pacific coast. The ancestors of G. wheatlandi dispersed from the Pacific to the Atlantic Ocean via the Arctic to meet G. aculeatus, which circled the globe from east to west. Full article

Juniperus L. is the second-largest genus of conifers, having the widest distribution of all conifer genera. Its phytogeographic history is, however, obscure due to its very poor fossil record. We described a wood of Juniperus sp. from the lower Maeotian sediments of the Popov Kamen section, Taman Peninsula, South Russia, in order to clarify its taxonomic position shedding light on the phytogeographic history of the genus. This fossil wood was well-preserved by mummification, which allowed for it to be studied by the same methods as used for the anatomical examination of modern woods. The wood from the Popov Kamen section shows the greatest similarity to the extant Mediterranean species J. excelsa, belonging to the section Sabina. This is the first reliable macrofossil evidence of the sect. Sabina from Eurasia convincingly dated to the Miocene. The age of the mummified wood from the Popov Kamen section is consistent with molecular dating of diversification of the lineage comprising juniper species of the sect. Sabina from Europe, Asia and eastern Africa. The wood of Juniperus sp. has not been buried in situ, as it was found in the relatively deep-water marine sediments. The available coeval pollen series and macrofossils of Cupressaceae from the surrounding regions suggest that this wood was likely transferred by sea current from the northwestern side of the Black Sea, which was a part of the Eastern Paratethys. Full article

The Late Miocene evolution of the Eastern Paratethys Sea was marked by significant palaeogeographical transformations. The knowledge of them should be improved with the information from the peripheral parts of this semi-enclosed marine basin. The study area corresponds to the Rostov Dome where the northern shore of the Eastern Paratethys is widely documented. The information from the previously published work, going back to the beginning of the 20th century, is collected. Its analysis allows us to document the spatial distribution of Middle Sarmatian–Late Maeotian (Tortonian–Messinian) deposits. The results shed light into the palaeogeographical changes in the Tanais Bay of the Eastern Paratethys Sea, which included the short-term hiatus at the Middle/Late Sarmatian boundary, the Early Maeotian regression, and the gradual Late Maeotian ingression when the bay re-established, but with a different configuration. These changes and the overall spatial distribution of the studied deposits cannot be explained by only the fluctuations in the level of the Eastern Paratethys and the desiccation episodes established in its central part. Most probably, the local tectonic uplifts were an important driver of the Late Miocene evolution of the Tanais Bay. Full article

Lithostratigraphy and isotopes of Paleogene sequences consisting mainly of terrestrial clastics and limestone were examined in the northern Fergana Basin of Uzbekistan. The studied sections consisted of two facies: the lower sequence coarse-grained terrestrial clastics and the upper sequence limestone clastics characterized by limestone beds. The sulfur isotopic composition of the bivalve obtained from the lower sequence was relatively low, namely, 14.94–16.82‰, which is equivalent to the Early Cretaceous; however, it is possible that the isotopic composition differed from that obtained in open seawater due to the presence of terrestrial clastics and the freshwater effect. In contrast, the sulfur isotopic composition of limestone from the upper sequence was relatively high, namely, 19.37–21.19‰, thereby indicating that they were likely to originate from the Early to Middle Eocene. Furthermore, the strontium isotopic compositions of the lower and upper sequences were 0.707772–0.707875‰ and 0.707812–0.708063‰, respectively. These values are more similar to those of the Paleogene than the Cretaceous. Finally, lithostratigraphy and age determination allowed us to correlate the upper sequence with representative limestone from the fourth transgression of the proto-Paratethys Sea, whilst the limestone beds were deduced to be remnants of the Eocene marine incursion of the proto-Paratethys Sea. Full article

(1) The ancient Paratethys Sea was a spacious inland salt-water basin, extending from the Alps, over Central Europe, to Central Asia. The southwestern part of its central area, the Croatian part of the Pannonian Basin System (CPBS), is generally known for shallow-water deposition and biota. The main purpose of this paper is to emphasize the significance of its less widespread deeper-water deposits in environmental and applied geology. (2) The authors consulted the previously published data, combined with their own results, obtained from the paleontological and sedimentological research, seismic stratigraphy and well-log analyses. (3) During our research in the CPBS, we noticed the connection between the tectonic structures and deep marine canyons and depressions within the Paratethyan shallows. Such structures can be recognized on well-logs and seismic or surface outcrops. They are situated along the faults, and deposits are characterized by the domination of pelagic over the benthic biota, sometimes with visible selective dissolution of aragonite/calcite tests. (4) Studied sedimentary sequences from these structures proved to be a precious source of data on the transgressive-regressive cycles, ancient migrations, modes of deposition and hydrocarbon formation during the Miocene Epoch in the CPBS. Full article

The introduction of modern methods for the mathematical processing of geological data is one of the promising areas of study and development in the field of geosciences. For example, today mathematical geology makes it possible to reliably identify astronomical cycles by measuring the scalar magnetic parameters of rocks (magnetic susceptibility). The main aim of this study is to develop a mathematical tool for identifying stable oscillation cycles (periods) in the dataset of the magnetic susceptibility of rocks in a geological section. The author’s method (algorithm) is based on the concept of discrete mathematical analysis—an innovative mathematical approach to the analysis of discrete geological and geophysical data. Its reliability is also demonstrated, by comparison with the results obtained by classical methods: Fourier analysis, Lomb periodogram, and REDFIT. The proposed algorithm was applied by the authors to analyze the material of field geological studies of the Zhelezny Rog section (Taman Peninsula). As a result, stable cycles were determined for the Pontian and Lower Maeotian sedimentary strata of the Black Sea Basin (Paratethys). Full article

Brizziite, a rare sodium antimonate (NaSb⁵⁺O₃), and fluorcalcioroméite ((Ca,Na)₂Sb⁵⁺₂O₆F), have been identified in two boreholes (Pasternik and Włosienica) which are situated 50 km apart. Both wells are located west of Krakow, Poland, and were drilled in the Miocene strata of the Paratethys Sea (a remnant of the Tethys Ocean). The Sb minerals are scattered in a solidified light blue silica gel within marls and layered clays. They occur most often as anhedral grains up to 20 μm in size. The presence of these phases was confirmed by Raman spectroscopy (RS) and X-ray diffraction (XRD). The brizziite from this study represents a secondary mineral after the alteration of roméite within a supergene zone, or crystallization from Sb-rich solutions derived by the leaching of the weathered primary roméite. Hence, the calcium and fluorine admixtures in their composition, determined by EPMA, indicate intergrowths of brizziite and roméite on the micro- to crypto-scale. The presence of the antimony in the study area is related to rejuvenated Old-Paleozoic polymetallic ore-mineralization occurring in the basement of the Krakow-Silesia Monocline. The phenomenon of the repeatability of brizziite in Pasternik and Włosienica, distant by several tens of kilometers, can be explained by the following three steps: (i) the penetration of the chloride ions from the drying up seawaters of the Paratethys Sea into the Miocene groundwater system, (ii) the mobilization of Sb⁵⁺ in the form of chloride complexes, and, finally, (iii) the transportation of the Sb-bearing solutions within the marly and clay sediments. Full article

In 2016, an extensive fossil forest was discovered near Meshgin Shahr, northwest Iran. Silicified tree trunks occur in Miocene fluvial sediments and at multiple stratigraphic levels within a 27-m thick sequence of Pleistocene volcaniclastics. The Miocene trunks likely represent stream transport. Pleistocene examples originated during repeated eruptive events when volcaniclastic sediments buried a standing forest. The site, informally named Meshgin Shahr Fossil Forest, was registered in 2017 as a national natural monument by the Iranian Cultural, Handicraft and Tourism Organization. To date, 16 fossilized trunks have been found, all but one of them representing gymnosperms. The ancient coniferous forest was very different from modern forests in Iran and adjacent Azerbaijan, a result of climatic changes that were principally caused by the demise of the Paratethys Sea and by rain shadow effects caused by the uplift of the Alborz and Zagros mountain ranges. X-ray diffraction patterns reveal that woods from the fossil forest contain three types of silica: opal-CT, pure quartz, and a mixture of opal-CT and quartz. In addition, optical photomicrographs show the abundant presence of amorphous opal-A. Mineralogic variations occur among different fossil trees and within a single trunk. These silica polymorphs resulted from a combination of processes: silica minerals precipitated in multiple episodes under differing geochemical conditions and the diagenetic transformation of an opaline parent material. Full article

The Late Mesozoic–Cenozoic topographic and climate evolution of Central Asia remains highly debated. The final retreat of the proto-Paratethys Sea from the western Tarim Basin is thought to correspond in time with the onset of tectonic uplift in the Pamir, Tian Shan and Altai ranges, as well as with regional aridification. The oxygen and carbon isotope compositions of the sediment deposits in the various Central Asian basins have already been used to decipher both the topographic and climatic changes that occurred in that region during the Cenozoic, generally concentrating on one sedimentary section and/or on a limited time range and either using multiple-type samples including sandstone calcitic cements, marine carbonates, fossils, or paleosols. In order to get a homogeneous dataset, minimizing variations in the isotopic composition of the material depending on its type and/or depositional environment, we selected only calcareous paleosols sampled in several continuous sections covering a wide time range from the Late Jurassic to the Pliocene. Our sampling also covers a wide area encompassing the whole Tian Shan region, which allows detecting regional variations in the δ¹⁸O and δ¹³C values. We show that the influence of the distance to the proto-Paratethys Sea on the paleosol δ¹⁸O record was not significant. Besides local factors such as the occurrence of large lakes that can have a significant effect on the isotopic composition of the calcareous paleosols, the long-term evolution of both the δ¹⁸O and δ¹³C values possibly reflects the hypsometry of the river drainage systems that bring water to the basins. However, as it is commonly accepted that the δ¹⁸O of soil carbonates is controlled by the δ¹⁸O of in-situ precipitation, this last conclusion remains to be further investigated. Full article