Paleozoic Research Articles

«Історична» колекція викопних безхребетних з нижньопалеозойських відкладів Богемського масиву (Чехія) як об’єкт наукової та культурної спадщини

The years 2022 marks the 95th anniversary of the foundation of the Geological Museum, the predecessor of the Department of Geology of the National Museum of Natural History NAS of Ukraine. However, the origins of its collections date back to the 19th century. The aim of the article is the ancient regional paleontological collection, which consists of fossil remains of various systematic groups of fauna and flora from the Lower Palaeozoic of the Bohemian Massif (Czech Republic) and is stored under #582. Various aspects of its value, primarily scientific and historical, were identified and characterised. The territory from which the collection originates is recognised as key in the knowledge of stratigraphy and palaeontology of the Lower Palaeozoic. The temporal range of fossils in the collection is Middle Cambrian to Middle Devonian. Fossil remains were collected from 45 localities, of which 2 are Cambrian, 15 are Ordovician, 16 are Silurian, and 12 are Devonian. The collection consists of two parts. The first contains 545 specimens of trilobite fossil remains. Trilobites in the collection are represented by all (11) currently known orders, 29 families, 105 genera, and 140 species (138 species according to the modern classification). The second part of the collection consists of 325 specimens of representatives of other characteristic faunal groups of the Lower Palaeozoic of the Bohemian Massif. This fauna associated with trilobites is represented in the collection by eight phyla (cnidarians, arthropods, molluscs, bryozoans, brachiopods, echinoderms, semichordates, and chordates) and 23 classes. The systematic composition of the second (non-trilobite) part of the collection includes more than 100 (!) species. A systematic catalogue of the collection, demonstrating its significant taxonomic diversity, has been compiled. The owner of the collection was the Mineralogical Cabinet of St. Volodymyr Imperial University of Kyiv, to which ‘the collection of Bohemian Silurian fossils’ in the amount of 1051 specimens arrived in 1874 ‘from the Bohemian Museum with the help of Prof. Jan Krejčí’ by purchase. The collection has an important scientific, educational, exhibitional, and historical value. Individual groups of the fauna of the collection are subject to revision and may become the object of research in numerous scientific works.

Evolution of an intermediate C4 photosynthesis in the non-foliar tissues of the Poaceae.

Carbon concentrating mechanisms (CCMs) in plants are abaptive features that have evolved to sustain plant growth in unfavorable environments, especially at low atmospheric carbon levels and high temperatures. Uptake of CO2 and its storage in the aerenchyma tissues of Lycopsids and diurnal acidity fluctuation in aquatic plants during the Palaeozoic era (ca. 300Ma.) would represent the earliest evolution of a CCM. The CCM parts of the dark reactions of photosynthesis have evolved many times, while the light reactions are conserved across plant lineages. A C4 type CCM, leaf C4 photosynthesis is evolved in the PACMAD clade of the Poaceae family. The evolution of C4 photosynthesis from C3 photosynthesis was an abaptation. Photosynthesis in reproductive tissues of sorghum and maize (PACMAD clade) has been shown to be of a weaker C4 type (high CO2 compensation point, low carbon isotope discrimination, and lack of Rubisco compartmentalization, when compared to the normal C4 types) than that in the leaves (normal C4 type). However, this does not fit well with the character polarity concept from an evolutionary perspective. In a recent model proposed for CCM evolution, the development of a rudimentary CCM prior to the evolution of a more efficient CCM (features contrasting to a weaker C4 type, leading to greater biomass production rate) has been suggested. An intermediate crassulacean acid metabolism (CAM) type of CCM (rudimentary) was reported in the genera, Brassia, Coryanthes, Eriopsis, Peristeria, of the orchids (well-known group of plants that display the CAM pathway). Similarly, we propose here the evolution of a rudimentary CCM (C4-like type pathway) in the non-foliar tissues of the Poaceae, prior to the evolution of the C4 pathway as identified in the leaves of the C4 species of the PACMAD clade.

Astronomically paced climate evolution during the Late Paleozoic icehouse-to-greenhouse transition

Late Paleozoic deglaciation is Earth's first icehouse-to-greenhouse transition with extensive vegetation, but the response of tropical climate to this transition has not yet been fully addressed. Here, cyclostratigraphic analysis was conducted on the magnetic susceptibility (MS) record of a deep marine carbonate succession in South China to construct the astrochronology of late Cisuralian (Early Permian), and decipher the evolutionary response to the climate transition in the MS and δ13Ccarb time series. The constructed astronomical time scale indicates an age of 272.83 ± 0.2 Ma for the Cisuralian–Guadalupian boundary in South China. Synchronizing global records demonstrates a complicated linkage between low and high latitudes, involving secular changes in atmospheric pCO2, ice volume, tropical climate and carbon cycling. In the final stage of the Early Permian icehouse (~290–288.2 Ma), the delivery of moisture from low to high latitudes was reduced in comparison with that in the icehouse apex. A more humid climate facilitated the development of tropical coal forests and more storage of 12C on land. In a full greenhouse condition (~281–272 Ma), the tropical responses to a rise in atmospheric pCO2 involved continental drying and ocean stagnation. On a shorter time scale, the nodes of 1.36 Myr obliquity cycles triggered ice-sheet expansion and enhanced tropical precipitation during an icehouse condition. With the gradual transition to an arid greenhouse, the insolation-climate relationship began to change at ~285.1 Ma, and the obliquity nodes became associated instead with terrestrial aridity and marine anoxia. These results bring into a focus pattern of shifting dynamics involving Earth's astronomical parameters and climate change for icehouse and greenhouse worlds in the Late Paleozoic Era.

Terrestrial forcing of marine biodiversification

The diversification of the three major marine faunas during the Phanerozoic was intimately coupled to the evolution of the biogeochemical cycles of carbon and nutrients via nutrient runoff from land and the diversification of phosphorus-rich phytoplankton. Nutrient input to the oceans has previously been demonstrated to have occurred in response to orogeny and fueling marine diversification. Although volcanism has typically been associated with extinction, the eruption of continental Large Igneous Provinces (LIPs) is also a very significant, but previously overlooked, source of phosphorus involved in the diversification of the marine biosphere. We demonstrate that phosphorus input to the oceans peaked repeatedly following the eruption and weathering of LIPs, stimulating the diversification of nutrient-rich calcareous and siliceous phytoplankton at the base of marine food webs that in turn helped fuel diversification at higher levels. These developments were likely furthered by the evolution of terrestrial floras. Results for the Meso-Cenozoic hold implications for the Paleozoic Era. Early-to-middle Paleozoic diversity was, in contrast to the Meso-Cenozoic, limited by nutrient-poor phytoplankton resulting from less frequent tectonism and poorly-developed terrestrial floras. Nutrient runoff and primary productivity during the Permo-Carboniferous likely increased, based on widespread orogeny, the spread of deeper-rooting forests, the fossil record of phytoplankton, and biogeochemical indices. Our results suggest that marine biodiversity on geologic time scales is unbounded (unlimited), provided sufficient habitat, nutrients, and nutrient-rich phytoplankton are also available in optimal amounts and on optimal timescales.

Differential Accumulation of Metabolites and Transcripts Related to Flavonoid, Styrylpyrone, and Galactolipid Biosynthesis in Equisetum Species and Tissue Types.

Three species of the genus Equisetum (E. arvense, E. hyemale, and E. telmateia) were selected for an analysis of chemical diversity in an ancient land plant lineage. Principal component analysis of metabolomics data obtained with above-ground shoot and below-ground rhizome extracts enabled a separation of all sample types, indicating species- and organ-specific patterns of metabolite accumulation. Follow-up efforts indicated that galactolipids, carotenoids, and flavonoid glycosides contributed positively to the separation of shoot samples, while stryrylpyrone glycosides and phenolic glycosides were the most prominent positive contributors to the separation of rhizome samples. Consistent with metabolite data, genes coding for enzymes of flavonoid and galactolipid biosynthesis were found to be expressed at elevated levels in shoot samples, whereas a putative styrylpyrone synthase gene was expressed preferentially in rhizomes. The current study builds a foundation for future endeavors to further interrogate the organ and tissue specificity of metabolism in the last living genus of a fern family that was prevalent in the forests of the late Paleozoic era.

Palaeobiogeographical analysis of the Mississippian (early Carboniferous) brachiopod fauna in the Tibetan Plateau

The Tibetan Plateau comprises several allochthonous terranes/blocks originated from the northern margins of eastern Gondwana. Brachiopod faunas from different terranes were referred either to Gondwana province or Cathaysia province through the Late Palaeozoic. They are very important in studying the palaeobiogeography regarding the early development of the Palaeotethys Ocean. However, due to tectonic complexity and uneven research in fossil groups through time, the palaeobiogeographical connections and geodynamic history of these terranes in the Mississippian (early Carboniferous) remain ambiguous. In this study, the brachiopod dataset was compiled and reviewed at three critical intervals in the Mississippian (Tournaisian, early Viséan, and late Viséan), based on material from 13 sections in the Tibetan Plateau (the Himalaya, Lhasa, North Qiangtang, and Qamdo) and those from adjacent areas in the Qaidam terrane, Baoshan terrane, Kashmir, Alborz Mountains, and western Australia. We utilized a community detection approach from network theory that incorporates presence-absence patterns of brachiopod genera. The results demonstrated increasing provinciality and endemicity through Tournaisian-Viséan, and supported a trend for the North Qiangtang and Qamdo terranes from the transition zone in the Tournaisian and early Viséan to a station far from the northern Gondwana margins since the late Viséan. This evidence further proves that the Longmu Co-Shuanghu suture zone serves as an effective palaeobiogeographic barrier and represents the main branch of the Palaeotethys Ocean during the Mississippian. The remarkable palaeogeographical reconfiguration represented by the significant palaeobiogeographical fragmentation appropriately indicates a moderate to low palaeolatitude for the North Qiangtang and Qamdo terranes regarding a persistently widening eastern Palaeotethys Ocean in the late Viséan.

The moldic pore evolution of the Middle Ordovician sabkha dolostone in Ordos Basin, China: A study based on the petrographic and geochemical characteristics of pore fillings

In the Ordos Basin, the sabkha dolostone reservoir with moldic pores of the fifth Member in the Middle Ordovician Majiagou Formation (M5) dominated the gas production of the Lower Palaeozoic. Recent research studies revealed the complex history of the moldic pore evolution, which intensively affected the reservoir potential evaluation. The moldic pores were formed by dissolution of the gypsum concretion and then experienced a different extent of multi‐phase filling. In order to understand the evolution of the moldic pores and explain its affection on the development of reservoirs, comprehensive petrographic and geochemical analysis including the cathodoluminescent, scanning electron microscope, trace and rare earth elements in situ, and strontium isotopes have been utilized to study the moldic pore fillings. The results reveal the moldic pore evolution: (a) the gypsum concretions were dissolved and the moldic pores were formed in the early diagenetic stage; (b) the calcite fillings formed in the vadose zone and phreatic zone during the early diagenetic stage in the sabkha environment; (c) the ferroan dolomites formed during the process of conversion of montmorillonite to illite at the burial diagenesis stage, at the burial depth of 3,500 m–4,000 m in the middle‐Late Jurassic. Significantly, filling in the late burial period is more conducive to the pore preservation compared with the filling in the early diagenetic stage, and the formation of the sabkha dolostone reservoir lies in the preservation of pores in the early diagenetic stage. Consequently, the results of this study provide a framework to differentiate the petrographic and geochemical characteristics of kinds of pore fillings and to understand the moldic pore evolution and its affection on the development of reservoirs in similar sedimentary environments.

Mechanism for the formation of natural fractures and their effects on shale oil accumulation in Junggar Basin, NW China

Despite the importance of natural fractures in shales, few techniques are currently available to examine their formation mechanism and effects on shale oil accumulation directly. The Middle Permian Lucaogou Formation in the Jimsar Sag of the Junggar Basin is a typical fractured shale. The Jimsar Sag has experienced multiple phases of tectonic movement since the Paleozoic Era, forming numerous natural fractures. However, controversy still surrounds the timing of formation, genetic mechanisms, and effects on shale oil accumulation of these fractures. Based on C-O-Nd isotopes, rare earth elements, fluid inclusions, SmNd isochron dating of fracture cements, rock acoustic emission, and triaxial rheological experiment, this study precisely define the fracture formation time, trace the provenances of fluids filling the fractures, elucidate the genetic mechanism of fractures and their effects on shale oil accumulation. The results suggest that these fractures were mainly formed in the Late Permian, Late Jurassic, and Early Cretaceous. Palaeotectonic stress field simulations further show that the tectonic movements in the Late Permian formed nearly N-S-trending fractures due to severe north-south extrusion. High-temperature fluids originating from the post-collision mantle intruded the Lucaogou Formation between ~258.1 Ma and ~ 257.6 Ma. Subsequently, tectonic movements in the Tianshan Mountains during the Late Jurassic resulted in extrusion from southwest to northeast, forming NEE-trending fractures. During this tectonic event, basin fluids intruded the Lucaogou Formation between ~150.2 Ma and ~ 146.5 Ma. The persistent fold rollback that occurred in the Bogda piedmont foreland sag in the Early Cretaceous subjected the Jimsar Sag to severe extrusion, forming NNW-trending fractures. This tectonic event influenced the intrusion of basin fluids into the Lucaogou Formation between ~123.0 Ma and ~ 120.3 Ma. The Late Jurassic and Early Cretaceous fractures coincided with the peak of oil generation and expulsion in the Lucaogou shale and created conduits and reservoir volumes for the migration and accumulation of shale oil. Our study introduces a new approach that integrates geophysical and geochemical data to investigate the formation processes of fracture and their impact on shale oil accumulation.

Whole-Rock Geochemistry, Zircon U-Pb geochronology and Lu-Hf isotopic constraints on metasedimentary rocks (Paragneisses) in Stornes Peninsula, Larsemann Hills，East Antarctica

ABSTRACT Understanding the geological history of the Larsemann Hills and other exposures along the southeastern coast of Prydz Bay is essential for reconstructing the formation and evolution of the East Gondwana continent. This research involves analyses of the major elements, trace elements, REE, U-Pb and Lu-Hf isotopes of zircons from the metasedimentary rocks found in the Larsemann Hills. The results suggest that the provenance of the metasedimentary rocks within the Larsemann Hills is mainly Mesoproterozoic to early Neoproterozoic magmatic rocks. The age of the protolith of the metasedimentary rocks is between ~1019 and ~970 Ma. Our data show that at least two tectono-metamorphic events at ~913 Ma and ~552–555 Ma affected the metasedimentary rocks. Furthermore, Prydz Bay has been an integral whole since before the Palaeozoic era and was subsequently reactivated by Pan-African tectonic events. The thickened crust stretched and thinned, accompanied by partial melting of lithospheric mantle into the lower crust. The real Prydz Bay Pan-African collision orogenic belt should be located under the ice sheet east of the Grove Mountains and strikes close to north-northeast.

A trans-Iapetus transform fault control for the evolution of the Rheic Ocean: Implications for an early Paleozoic transition of accretionary tectonics

AbstractThe Paleozoic era begins with the final assembly of Gondwana and ends with the amalgamation of the supercontinent Pangea. Although this tectonic progression is generally well documented, one fundamental but under-studied phenomenon during this era is the transition from two-way to one-way (northward) migration of peripheral terranes between Gondwana and Laurentia-Baltica from Cambrian to Ordovician time. The two-way terrane accretion was likely initiated during the opening of the Rheic Ocean at ca. 510 Ma when several Gondwana-derived terranes comprising Carolinia, Ganderia, Avalonia, and Meguma sequentially drifted from the northern margin of Gondwana and eventually collided with Laurentia or Baltica. Over the same time interval, the Laurentia-derived Cuyania terrane (a.k.a., the “Precordillera terrane” is commonly believed to have accreted to the proto-Andean margin of Gondwana, whereas the peri-Laurentian/Dashwoods ribbon continent separated from, then re-accreted to, the Laurentian margin after being trapped during the collision of the Taconic arc. Alternatively, the Cuyania terrane is suggested to have remained attached to the Ouachita Embayment throughout the Cambrian–Ordovician, and then passed onto Gondwana during the collision between the proto-Andean margin and the hypothesized Texas Plateau at the leading edge of Cuyania. Here we explain the enigmatic, pene-contemporaneous migration of these peripheral terranes by a trans-Iapetus transform fault that was likely active between 510 and 450 Ma and extended from the proto-Appalachian margin of Laurentia to the proto-Andean margin of Gondwana. The trans-Iapetus transform fault terminated after the respective accretion of Carolinia and Ganderia to the proto-Appalachian margin and of Cuyania to the proto-Andean margin. We interpret the development of the trans-Iapetus transform during the Cambrian–Ordovician to be a consequence of the global geodynamic transition from the break-up of Rodinia (continents/terranes drifting away from Laurentia) to Pangea amalgamation (continents/terranes drifting toward assembling Laurussia).

Major Early-Middle Devonian oceanic oxygenation linked to early land plant evolution detected using high-resolution U isotopes of marine limestones

The middle Paleozoic (∼420-350 Myr) records a major increase in ocean-atmosphere oxygen levels; however, the timing and pattern of oxygenation are poorly constrained. Two well-dated North American locations in Nevada and Illinois were used to generate a high-resolution U-isotopic profile (δ238U) spanning ∼70 Myr of the middle Paleozoic. Stratigraphic and geochemical data support the interpretation that the Nevada profile represents a near-primary record of global-ocean redox variations. First-order δ238U trends indicate strongly reducing oceans during the late Silurian and Early Devonian, terminated by a major oxygenation event near the Emsian-Eifelian boundary (∼395 Ma). More oxic seawater conditions persisted for the next 30+ Myr, but were punctuated by multiple Myr-scale anoxic events during the Middle-Late Devonian and Early Mississippian that correlate with known global biotic crises, positive δ13C excursions, and widespread organic-rich facies deposition. The timing of the ∼395 Ma oxygenation event suggests that the O2 rise was the result of increased photosynthesis and organic carbon burial linked to diversification of late Silurian to earliest Middle Devonian terrestrial plants, rather than to subsequent Devonian increases in terrestrial plant root depth, tree height, lignin content, or seed reproduction. These findings demonstrate that early colonization of continents by relatively small, shallowly rooted plants with geographically limited ranges was sufficient to drive long-term oxygenation of the ocean-atmosphere system, paving the way for the evolution of large, mobile animals that have dominated the Earth's surface since the middle Paleozoic.

Zircon U-Pb Dating for Paragneiss in the Xinxian Area in the Dabie–Sulu Orogenic Belt and Its Geochemical Characteristics

In order to understand the subduction of the Yangtze block and its collision with the North China Craton, we performed the elements analysis and zircon U-Pb dating on paragneiss from Xinxian area, which located along the west edge of the Dabie-Sulu ultrahigh-pressure (UHP) metamorphic belt. The major elements analysis showed SiO2, Al2O3, and K2O were enriched and the rare-earth element (REE) analysis showed the paragneiss had a high content of REEs, especially light rare Earth elements (LREEs). The elements analysis suggest that the protolith of paragneiss may be formed by terrestrial materials. As reflected by cathode luminescence (CL), zircon in rocks was metomorphic and had a core-edge microstructure. The edge of zircon was dated by LA-ICP-MS at 233 ± 24 Ma, which suggests that the paragneiss was formed later than the Triassic. The inherited zircon had a large age range of 456–1,727 Ma, mainly in the range of 705–811 Ma. The wide range of ages suggests that the protolith of paragneiss was sedimentary rocks formed no earlier than the Paleozoic. And the paragneiss from Xinxian area were generated in the Dabie-Sulu ocean basin or abortive ocean basin in the Paleozoic era.

Embryos, cancers, and parasites: Potential applications to the study of reproductive biology in view of their similarity as biological phenomena.

BackgroundAt present, there are so many living things on the earth. Most of these organisms have a reproductive strategy called sexual reproduction. Among organisms that reproduce sexually, mammals have an extremely complex and seemingly unnatural method of reproduction, or viviparity.MethodsAs an approach to understanding the nature of viviparity, the author have tried to outline the common life phenomena of embryos, cancers, and parasites based on the literature to date, with internal parasites as the keyword.Main findingsEmbryo, cancer, and parasite are constituted as a systemic interaction with the host (mother). Based on these facts, the author proposed the hypothesis that in the case of mammals, "the fetus is essentially harmful to the mother", and that the parasitic fetus grows by skillfully evading the mother's foreign body exclusion mechanism.ConclusionComparative studies of "embryos", "cancers", and "parasites" as foreign bodies have the potential to produce unexpected discoveries in their respective fields. It is important to consider the evolutionary time axis that the basic structure of our mammalian body arose over 200 million years from the Mesozoic Triassic, the period immediately after the Paleozoic Era, when life on Earth became massively extinct.

DISCOVERING THE KRAYAN HIGHLAND GEODIVERSITY AND GEOTOURISM POTENTIAL INDONESIA


 
 
 
 The Krayan Highland located in the west of Nunukan Regency, North Kalimantan Province, with a history of the earth dating since the Paleozoic era 570-251 million years ago. The area has a beautiful landscape of mountains and hills, home to the local indigenous people called the Dayak Lundayeh Tribe. Krayan Highland is rich in geodiversity, biodiversity and culture diversity. The area has been least developed in terms of infrastructure compared to other areas in the country. The research aims to find and map the geodiversity and geotourism potential of the Krayan Highland. The research method is qualitative method, which data collection is conducted through desk study and field survey. Descriptive, map analysis and content analysis is conducted during this research. The research discovers rich geodiversity in the area, one of them in the Kubah Garam (salt Dome). The Dayak people utilize the salt in the mountain and develop it into a geoproduct with their local indigeneous knowledge. The Krayan Highland has the potentital to be further developed into an aspiring geopark in the future.
 
 
 

Newly discovered late Devonian and early Carboniferous ophiolite fragments in the Diyanmiao mélange in southeastern Inner Mongolia: Implications for the late Paleozoic tectonic evolution of the southeastern Central Asian Orogenic Belt

The Late Paleozoic tectonic evolution of the southeastern Central Asian Orogenic Belt (CAOB) has long been controversial, and one of the most contentious issues has been whether there was a collisional orogenic event during the Middle Paleozoic. Here we report the discovery of a Late Devonian (373.5 ± 6.8 Ma) ophiolite fragment in the Diyanmiao mélange of southeastern Inner Mongolia. This fragment, coupled with previously reported Carboniferous ophiolites in the same region, confirm the former presence of a Late Devonian ocean basin that evolved into the Carboniferous basin. The geochemical characteristics of the Devonian and Carboniferous mafic rocks in the ophiolites are consistent with evolutionary trends from mid-ocean ridge (MOR)-like to supra-subduction zone (SSZ) compositions. The presence of a Late Devonian-Carboniferous trench-arc-basin system in the region, which is represented by the Daqing-Diyanmiao and Bayan'aobao-Hongger ophiolite belts, the Baolidao arc, and the Erenhot-Hegenshan Oceanic Basin (EHB), confirms the presence of a late Devonian-Carboniferous orogenic belt in the southeastern CAOB. The western segment of the Baolidao arc was developed on continental basement (the Xilin Gol complex), whereas the eastern segment was formed on oceanic basement. This tectonic configuration is similar to that of the modern Aleutian arc, Kamchatka-Kuril Islands and Japan-Ryukyu arc system in the northern and western Pacific Ocean. During the early Permian the oceanic basin represented by the Erenhot-Hegenshan basin closed, and the Baolidao arc was accreted onto the southern continental margin of the Southern Mongolian continental block.

The formation of metrology as government regulated activity in France

The article has discussed the historical process of development of metrological activity in France. It was revealed that the history of metrology is considered as an auxiliary historical and ethnographic discipline from a social and philosophical point of view as the evolution of scientific approaches to the definition of individual units of physical quantities and branches of metrology. However, in the scientific literature, the little attention is paid to the process of a development of a centralized institutional metrology system that is the organizational basis for ensuring the uniformity of measurements. It was shown that traditionally there are two periods of development of metrology based on the unification of weights and measures: the association under Charlemagne and the introduction of the decimal metric system during the French Revolution. Because this division has a mixed scientific and organizational basis, a new periodization of the development of French metrology from the position of state regulation was proposed. The highlighted stages include the primitive period and the first city-states, the time of the domination of the Roman Empire, the era of the coexistence of many measures, the chapters of Charlemagne, the feudal practices of the Middle Ages, the creation of royal standards under Henry II, the introduction and dissemination of the decimal metric system, the emergence of metrological institutes, laboratories, centers. At the State level the first step in organizing a centralized institutional metrology system was the creation of a testing laboratory, the second was the creation of National Metrological Bureau, national bodies for metrology, and the third was reorganization of the system and appointment of the National Testing Laboratory as the governing metrological body of France. Thus, the French metrology system has experienced many crises and upheavals in the process of its formation. However, France today is one of the most experienced and respected countries in the field of metrology, and at the international level, it was the one who laid the foundations for new metrological agreements, as well as the social, philosophical, scientific, political and geographical area of the new system of measures and weights.

NATURAL RECREATIONAL RESOURCES OF CHORTKIV DISTRICT OF TERNOPIL REGION

The article presents a component-by-component analysis of natural recreational resources of the newly created territorial and administrative unit –Chortkiv district of Ternopil region. Geomorphological, water, biotic recreational resources are described. It is proposed to allocate the Chortkiv recreational area, which will include three recreational complexes: Monastyrysk and Buchach, Borshchiv and Zalishchyky, Chortkiv and Husyatyn. For the selected recreational complexes and nodes the types of recreational occupations according to the main groups of recreational resources are offered.The Monastyrysk and Buchach recreational complex has recreationally interesting landscapes that are part of the Dniester Canyon Landscape park, in particular the cascades of Rusylivsky and Sokiletsky waterfalls, the Zholoby cave (for cognitive recreation), and the mass recreation territory in the area of ​​the Lisova camp site, as well as the valley of the Strypa River from the village of Skomorohy (Buchach territorial community) to the village of Lytychi (Zalishchyky territorial community) for water tourism. Borshchiv and Zalishchyky recreational complex includes Borshchiv and Zalishchyky recreation centers and is characterized by very high recreational potential due to the aesthetic appeal of landscapes, a large number of living and inanimate objects, high climate comfort. The Dniester canyon, saturated with natural protection objects along its entire length, is favorable for the development of ecotourism, tourist and excursion cognitive recreation.Zalishchyky recreational center. Within the valley of the Dniester River in the vicinity of the village Khmelev, the valley of the river Dzhuryn near the village Nyrkiv and village Nahoryany (Chervonogorod waterfall) of Tovste territorial community, areas for mass recreation. The development of cognitive tourist and excursion recreation is promoted by Zhyzhavsk and Obizhevsk botanical reserves of national importance, in which forest and meadow and steppe groups with valuable relict shrubs are protected: Polish spiraea, Cyticus Podilskyy, dwarf cherry. Kasperivtsi Landscape Reserve of national importance with unique natural complexes in the valley of the Seret River with a picturesque reservoir, the presence of geological, paleontological and botanical objects of nature is a place of short-term recreation. In the valley of the Dniester and its tributaries there are ways to the surface of mineral waters – sulfate, chloride, like "Naftusya" or "Druskininkai" (Zalishchyky, Tovste), as well as medicinal peat bog (Tovste), which, in combination with a warm climate (climatotherapy), is the basis for the development of health and recreation.The unique flora of Western Podilsk Transdnistria is represented in Zhyzhavsk, Obizhevsk, Shutromyntsi, tract "Hlody" botanical nature reserves, can be the object of scientific and cognitive tourism for botanists, teachers, students, students of profile and secondary schools.Borshchiv recreation center also has a high recreational potential. Extremely interesting for the development of scientific and cognitive tourism are the outcrops of sediments belonging to the Paleozoic era (Trubchyn tract, Dzvenyhorodsk Silurian outcrops, Silurian and Devonian deposits in the Dniester, Khudykivsk outcrops of Lower Cretaceous deposits). In terms of completeness, number of fossil fauna and flora, accessibility for observation, most of them are of international importance and are stratotypes for the Eastern European platform.Chortkiv and Husyatyn recreation complex includes Husyatyn and Chortkiv recreation centers. Husyatyn recreation center specializes in the development of health and recreation. Husyatyn is a balneological resort with the use of low-mineralized water with a high content of organic substances such as "Naftusya" called "Novozbruchanska" and brines of high mineralization such as "Druskininkai" called "Husyatynska". Chortkiv recreational center specializes in short-term recreation, development of sports and recreation, which is facilitated by areas of river floodplains, slopes covered with forests, the river Seret for various types of water tourism.Key words: recreational resources, administrative district, recreational district, recreational complex.

Geochemistry of upper Palaeozoic ‘thin-layer’ limestones in the southern North China Craton: implications for closure of the northeastern Palaeotethys Ocean

AbstractDuring the late Palaeozoic Era, a series of related marine strata dominated by multi-layer limestones were deposited in the southern North China Craton. In order to gain new insights into the systematic geochemistry of the carbonate succession of the representative formation (Taiyuan Formation), we examined 59 limestone samples collected from the Huaibei Coal Basin (HCB), with a view towards quantitatively determining the major and trace elements and stable isotope compositions. The data obtained can provide essential evidence for reconstruction of the depositional palaeo-environment and tectonic setting of the Taiyuan Formation. Both X-ray diffraction analyses and palaeoredox proxies (e.g. V/Cr, V/(V + Ni) and authigenic U) indicated that the limestone layers were deposited in an oxic–dysoxic zone, with calcite as the main component. Moreover, palaeomagnetic evidence provided support for the conclusion that these limestones were laid down within an epicontinental sea depositional environment under a warm or hot palaeoclimate during the transition between late Carboniferous and early Permian time. Additionally, evidence obtained from our analyses of trace and rare earth elements revealed that the tectonic setting of the Taiyuan Formation (L1–L5) in the HCB transited from an open ocean to a passive continental margin, thereby indicating that this transformation stemmed from the subduction closure of the northeastern Palaeotethys Ocean. The findings of this study would be of interest to those working on the upper Palaeozoic marine strata in the southern North China Craton.

A ‘hermit’ shell-dwelling lifestyle in a Cambrian priapulan worm

The Cambrian 'explosion', about 530 million years ago, marks a rapid diversification of the major animal lineages1. A concomitant increase in the complexity of ecosystems is believed to have accelerated this evolutionary radiation2, but direct evidence of the ecological modes of Cambrian taxa is nevertheless scarce - even in exceptional Burgess Shale-type deposits3. Here, we present new fossil material from the Cambrian (Stage 4) Guanshan biota in southern China that reveals the consistent occurrence of the priapulan worm ?Eximipriapulus4 within the conical shells of hyoliths. This represents the first direct evidence of a 'hermiting' life strategy - the adoption of a different organism's exoskeleton - in the priapulans and within the Palaeozoic era. It highlights the intense degree of convergent evolution during the Cambrian radiation. Hermiting behaviour has previously been linked with the escalation of predation pressure during the Mesozoic marine revolution5; such intensity of predation may also have characterised early Cambrian oceans.

Trichinellosis among the human population in Vojvodina

The origin of the parasites of Trichinella species goes back to very ancient times–as far as the Paleozoic era, and the organism has been present in the territory of today’s Europe for millions of years. The first epidemic in the region of Serbia was reported in Zemun in 1923. Trichinellosis is the most important parasitic food borne disease in our country. In Vojvodina alone, 58 epidemic outbreaks were reported in the period 2015-2019 with 853 affected patients. The average incidence was 3.5 diseased individuals per 100 000 population. High morbidity and hospitalization rates and the occurrence of lethal outcomes qualifies trichinellosis as belonging to the category of relatively severe human diseases in Serbia. However, there are promising data indicating that implementation of relevant control measures and improvement of the awareness of the population have led to a statistically significant decrease in the number of diseased persons with trichinellosis in both Vojvodina and the entire country.