Reference Section Research Articles

Examining Rate and Pattern of Author Self-Citation in Nepalese Journals

This bibliometric study has explored the frequency of the author self-citation, investigated the structure of author self-citation, and explored the association in terms of the number of authors, number of references, and author self-citation in the article from 18 journals published by different departments/campuses of eight faculties/institutes of Tribhuvan University. All the selected journals are indexed in the Nepal Journals Online (NepJOL) database, the only indexing of Nepal. The study incorporated the most recent five journal issues, proportionally selected based on the representation of disciplines indexed in the database, from three faculties and five institutes of Tribhuvan University. The Faculty of Law was excluded due to the unavailability of journals. However, The Forestry: Journal of the Institute of Forestry, Nepal, was included despite having only four issues, to ensure representation of the discipline rather than excluding it entirely. Through the process, the study included 1,115 articles from 18 journals for descriptive and inferential analyses. Necessary information was manually collected from the articles to analyze the interconnectivity among the number of author self-citations, author(s), and references in the references section. As a result, author self-citation in journals varies from 11% in engineering to 70% in science and technology. The overall author self-citation rate is 29.6% in these 1,115 articles. Moreover, it is inferred that author self-citation is positively correlated with the number of authors per article and the number of references listed, and the self-citation behavior differs significantly across journals and faculties. In instances, where journals exhibit a high rate of author self-citation, it is recommended that editors and reviewers conduct a thorough review of the submitted manuscripts. Additionally, the study calls for a qualitative investigation to explore the underlying dynamics of the author self-citation. This investigation should determine whether the observed self-citations are an inherent aspect of scholarly practice or if they are strategically inserted for citation purposes in specific contexts.

The problem of ammonoid substantiation of the Artinskian–Kungurian boundary in Western Verkhoyanie

Kungurian ammonoids had high taxonomic diversity, but were distinguished by an extremely high level of endemism and sharp geographic differentiation. Therefore, outside the regions containing the most important conodont taxa, the Artinskian-Kungurian boundary based on ammonoids must be established through indirect evidence due to the lack of common species with potential global stratotypes of the lower boundary of the Kungurian. A long-term study of the reference sections of the Echian and Tumarian regional stages and their ammonoids made it possible to change the understanding of the bio- and lithostratigraphy of the Artinskian-Kungurian boundary deposits of the Kuranakh structural-facies zone of Western Verkhoyanie. Clarification of the upper boundary of the Khabakh Formation in the stratotype section led to the fact that the ammonoids previously belonging to this formation began to be considered in the lower part of the Orol formation. They characterize the Paratumaroceras? sp. nov. biostratigraphic beds of the lower part of the Tumarian Regional Stage. At the current level of knowledge, the ammonoid substantiation of the Artinskian–Kungurian boundary in Verkhoyanie is difficult due to the existing hiatus corresponding to the Khabakh formation and its age analogues. However, the appearance at the base of the Tumarian Regional Stage of the first paragastrioceratids with a ventral sinus in transverse sculpture (Paratumaroceras? sp. nov.) suggests that the boundary in question is located near the base of the indicated regional stage or even combined with it. For further clearer identification of the Kungurian lower boundary in Verkhoyanie, new studies of the Echian–Tumarian boundary deposits in typical sections, independent of paleontology, are necessary. Such research should primarily include isotope-stratigraphic subdivision and high-precision U-Pb dating.

Eight years of thin noise reducing asphalt layer monitoring in an urban environment

The City of Antwerp initiated a pilot project on thin noise reducing asphalt layers in an urban environment with the aim to investigate the behavior of the asphalt layers from a noise perspective with respect to urban traffic without neglecting the mechanical durability. Five thin asphalt layers were selected and compared with a reference section. The pavements were constructed in October 2016 on two different test sites. The construction was followed up extensively. The acoustical quality of the thin asphalt layers is followed up in time. Close-ProXimity (CPX) measurements are performed according to ISO 11819-2 within certain time intervals after construction to follow up the evolution. Texture measurements according to ISO 13473 are linked to the noise measurement results. Visual inspections are performed at regular intervals. The results of eight years of monitoring are discussed. While some test sections are already partially replaced, others are still in acceptable condition. The major concern in the STOLA project is to learn about a good balance between the noise reducing capacity of the chosen thin asphalt layers, a limited degradation of the noise performance during its lifetime and a good mechanical performance delaying ravelling and texture changes as long as possible.

The St. Meinrad Coal Member (Pennsylvanian)—Reference Sections from Spencer County, Indiana

The purpose of this study is to (a) specify locations in Indiana that can serve as reference sections for the St. Meinrad Coal Member (Pennsylvanian) and (b) acquire more data to better correlate this coal with its equivalents in the Illinois Basin. The work focused on 1) a core from Indiana Geological and Water Survey drill hole (SDH) 537, latitude 38.180721 N, longitude 86.83895 W); and 2) an outcrop of the St. Meinrad Coal Member (latitude 38.147652 N, longitude 86.808903 W), both in Spencer County, Indiana. The borehole was drilled in November 2023 and the core is archived at the Indiana Geological and Water Survey Core Research and Teaching Repository, Bloomington, Indiana, USA. The St. Meinrad Coal Member was encountered at a depth of 44.25 to 48.45 ft (13.49 to 14.77 m), with a total coal thickness of 4.20 ft (1.28 m). On a whole-seam basis, the coal has an ash yield of 1.27 wt % and is 3.92 wt % in total sulfur. Petrographically, the coal consists of moderate amounts of vitrinite (77.12 vol %), liptinite (15.84 vol %) and inertinite (7.04 vol %). Palynologically, the coal is dominated by lycopsid tree spores (74.12 vol %), with reduced amounts of small lycopsid (13.4 vol %) and tree fern (6.14 vol %) spores. Small fern (0.9 vol %) and calamite (4.17 vol %) spores are uncommon to rare, as is cordaite pollen (0.96 vol %). The outcrop location has a coal thickness of 3.15 ft (96 cm). In outcrop, the coal is relatively clean in the middle part and is enriched in mineral matter at the top and bottom parts of the seam. The coal is underlain by claystone. Palynologically, the coal has similar spore assemblage to that documented from the core. The common occurrence of Endosporites globiformis and other stratigraphically diagnostic taxa in both locations warrant assignment of the St. Meinrad Coal Member to the early Atokan NG (Microreticulatisporites nobilis - Endosporites globiformis) miospore zone of the Illinois Basin, which correlates with the early Duckmantian strata of western Europe and Middle-Late Bashkirian strata worldwide. The palynologic data also indicate that, within the Illinois Basin, the St. Meinrad Coal Member is coeval with the Hawesville and Bell coal beds in western Kentucky.

Magnetostratigraphy of the upper Jurassic and Lower Cretaceous deposits of the Bolshekhetskaya structural terrace

Relevance. The confinement of hydrocarbon deposits to certain stratigraphic horizons, poor knowledge of the northeast of Western Siberia and adjacent territories, including the magnetostratigraphic method, with their oil and gas potential (over the past 10 years, four unique hydrocarbon deposits have been discovered here), the boreal nature of the deposits, and the need for remote magnetostratigraphic correlations. Aim. To create a magnetostratigraphic reference section of the northeast of Western Siberia. Objects. Sections of deep wells of the Pendomayakhskaya, Vostochno Suzunskaya, Vostochno Lodochnaya and Gorchinskaya areas of the Bolshekhetskaya structural terrace, which exposed the Lower Cretaceous and upper parts of the Upper Jurassic (Yanovstan Formation) deposits. Methods. Paleomagnetic studies were carried out according to standard methods and included sampling of core samples with an "up-down" orientation, sample preparation (kappametry, marking of samples, photographing, sawing), measurement of magnetic susceptibility, temporary cleaning (the samples were located along the field during a week, then a week-against the field with determination of residual magnetization), complete demagnetization by alternating magnetic field, plotting of complete demagnetization, mass cleaning, determination of components of natural residual magnetization, assessment of paleomagnetic stability, identification of forward and reverse polarity zones, construction of paleomagnetic sections. To construct the magnetostratigraphic sections given in this article, the paleomagnetic and biostratigraphic data are linked. For this purpose, magnetochrons were identified using biostratigraphic analysis. Results. The authors have compiled a composite magnetostratigraphic section of the boundary Jurassic-Cretaceous deposits of the Bolshekhetskaya structural terrace and identified four magnetozones with subzones of direct and reverse polarity, compared with the Berriasian ammonite scale. The high information content of the results of magnetostratigraphy research under boreal conditions was noted.

Medical Students’ Satisfaction with References Services in Afe Babalola University, Ado Ekiti

The study was conducted on the medical students’ satisfaction with references services in Afe Babalola University, Ado Ekiti, Nigeria, while the data collected for the study were analyzed using frequency tables and percentage. Observation was used to determine the types of reference services and it was found that five (5) out of seven (7) reference services are provided in the library. these include CAS, user educator, Reprographic services, select dissemination of information, computerized reference sources and it was discovered that purpose of using reference section is that it enhancing the use of the resources and services of the library, it save precious time of the readers, supporting research and learning, leisure and recreation and it helps readers in locating the sources of information relevant to their needs, the study further discovered that referral services, Selective Dissemination of Information (SDI) Current awareness services, and Photocopying services that are used on a daily basis while it also discovered that inability of reference librarians to utilize new technologies to provide reference services, lack of policy implementation, lack of policy implementation, inadequate qualified staff and poor internet connectivity were the major problems affecting the provision of reference services. In conclusion the study made some recommendations which include that: management of the libraries should look toward the implementation of other medium of reference service delivery which has not been implemented in their libraries and there should be constant training and retraining of library personnel in the reference section to upskill and learn the new method of reference service delivery; and Library policies must be updated regularly.

Corticosteroids for Managing Pediatric Sepsis and Septic Shock: A Systematic Review and Meta-analysis.

To assess the efficacy and safety of corticosteroids for the management of pediatric sepsis and septic shock. Ovid MEDLINE, Ovid Embase, CENTRAL, Web of Science (Core Collection) and China National Knowledge Infrastructure were systematically searched up to September 2023. Preprint servers, clinical trial registries and the reference sections of previous reviews were hand-searched. Randomized controlled trials that enrolled pediatric sepsis, septic shock or systemic inflammatory response syndrome patients, compared the use of corticosteroid regimens against standard sepsis care and reported eligible outcomes were included. Title/abstract and full-text screening were conducted in-duplicate. Eligible articles were extracted using a standardized form in-duplicate. Outcomes extracted include mortality incidence, hospital and pediatric intensive care unit length of stay, duration of shock, incidence of adverse events and serious adverse events and incidence of corticosteroid-related adverse events. The risk of bias was assessed using the Revised Cochrane Risk of Bias Tool for Assessing Randomized Trials. Random-effects meta-analyses were conducted, and the quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach. Sixteen randomized controlled trials (N = 973) were included. Corticosteroid use may be associated with reduced mortality risks (risk ratio: 0.65, 95% CI: 0.50-0.85), shorter length of hospital stay (MD: -3.76 days, 95% CI: -6.66 to -0.86), and shorter pediatric intensive care unit length of stay (MD -2.34 days, 95% CI: -3.14 to -1.53 days). Corticosteroid use may be associated with gastrointestinal bleeding but not a higher risk of secondary infection. No studies reported on serious adverse events. All findings were based on low to very low quality of evidence. While corticosteroids show promise for managing pediatric sepsis and septic shock, the question of how to select the best candidate and the most optimal regimen remains unanswered. Future trials need to focus on assessing corticosteroid-related adverse events and stratifying patient inclusion by sepsis subphenotypes.

THE DEMISE OF THE MESSINIAN SALINITY CRISIS AND THE BEGINNING OF THE ZANCLEAN IN THE NORTHERN MEDITERRANEAN BASIN: INSIGHT FROM HIGH-RESOLUTION BIOMAGNETOSTRATIGRAPHY (POLLENZO SECTION, NW ITALY)

The Messinian-Zanclean boundary in the Mediterranean basin marks the end of the Messinian salinity crisis (MSC) at approximately 5.33 Ma. The mechanism behind the return to normal marine conditions after the MSC are debated, with two main hypotheses proposed: an instantaneous reflooding of the Mediterranean at the base of the Zanclean, following its near-complete desiccation, or a gradual sea level rise in a non-desiccated basin during the late MSC phase (Lago-Mare). Our objectives are to refine the age model of the Pollenzo section in the Piedmont basin, Italy, and to elucidate environmental variability during this phase. We employ high-resolution biomagnetostratigraphic and cyclostratigraphic analyses, integrated with statistical multivariate and cluster analyses, and tie the results with other Italian Mediterranean reference sections of the basal Zanclean. The proposed age model is based on biostratigraphic markers (planktic foraminifera and calcareous nannofossils), alongside the identification of the base of the Thvera subchron. Although no astrochronological tuning was proposed, the influence of orbital parameters variation on calcareous plankton was noted, especially at tie of eccentricity maxima. Our results indicate a gradual restoration of open marine conditions after the MSC, spanning from 5.33 to 5.23 Ma. We observe a transition from a more marginal environment to more open marine conditions at the termination of MSC. Our findings challenge the notion of an abrupt transition at the end of the MSC, emphasizing the gradual nature of environmental change in the northernmost Mediterranean basin, from the late Messinian to the early Zanclean.

The Opioid Crisis, Impact on Children, and Mitigation Strategies

The opioid epidemic continues to make a significant impact on public health across multiple domains. While patients with opioid use disorders (OUD) remain in the face of this epidemic, the effect of the opioid epidemic, including on children and families, remains unheard. The impact of the opioid crisis is felt the most by individuals who do not use opioids themselves, with children being the most vulnerable victims of the opioid epidemic, an aspect of this epidemic that receives far less attention. The socio-ecological model approach is used to increase awareness of the lived experiences of children growing up in households with OUD and to promote the incorporation of treatment considerations based on available research. A literature review was conducted using computer-based searches using PubMed, PsycINFO, Medline, and Google Scholar databases. This entailed searching according to the following keywords (or stems when possible): opioids, opioid overdose, parental opioid use, child maltreatment, resilience, and adverse childhood experiences. Keywords were combined by using the Boolean operators "AND" and "OR.". Additionally, the ancestry approach, where potential studies were identified from the reference sections of existing reviews on the association between opioids and children, was used. Given that prenatal opioid use is extensively studied, and our focus was on lived experiences, studies focused solely on the effects of prenatal opioid use were excluded. Selected studies were varied in scope and methodologies. We reviewed the bibliographies of identified studies for additional studies and used both forward and backward searching. The economic cost of OUD and fatal opioid overdose is staggering and estimated to be about $1.02 trillion. Exposure to parental opioid use in childhood can have a significant impact on children's current and future lives. Conversely, for parents with OUD, children often provide a strong motivation for treatment. Children of adults with OUD are at higher risk of early exposure and initiation of opioid misuse. Opioid exposure in childhood, in turn, is associated with adult opioid misuse and OUD. Screening at healthcare visits is advocated to detect and mitigate the impact of OUD on children. The odds of using school-based mental health services are greater in boys compared to girls. Emerging evidence suggests that boys manifest less resiliency in the face of parental opioid exposure. This indicates a more nuanced understanding of the developmental outcomes of parental opioid exposure.

Estimating the number of Canadians suffering from fecal incontinence using pooled prevalence data from meta-analysis

Background and aimFecal incontinence (FI) is defined as the unintended loss of solid or liquid stool. FI adversely affects the patient’s quality of life. However, due to stigma, lack of awareness, and underdiagnosis, there is a notable gap in the knowledge regarding its prevalence. This study aimed to conduct a systematic review and meta-analysis of published literature reporting on FI prevalence and estimate the number of people afflicted by FI.MethodsA systematic review was conducted following the PRISMA 2020 guidelines, using the Embase, MEDLINE, CINHAL, and PubMed databases to identify relevant publications in the English language. Two reviewers independently screened the articles and extracted data. The reference sections and content of the review papers were also evaluated. Thirty-two articles were selected and included. A meta-analysis of proportions was performed using RStudio software. A sub-analysis was conducted to account for the variation between sample population age groups to minimize heterogeneity. The pooled prevalence was extrapolated to the Canadian population and a sample of ten densely populated countries to estimate the number of people affected by FI.ResultsThe Mean pooled FI prevalence in men and women was 7% (95% CI: 6-9%) and 10% (95% CI: 8-12%), respectively. The sub-analysis mean pooled prevalence of FI in men and women was 8% (95% CI: 6-10%) and 10% (95% CI: 8-12%), respectively. The authors estimate that between 1 and 1.5 million Canadians and 320 to 500 million people in the ten most populous countries suffer from FI.ConclusionFecal incontinence is a prevalent underdiagnosed condition requiring appropriate and timely treatment to improve a patient’s quality of life.

Study of the hydraulic characteristics of an airfoil‐shaped weir trough measurement and control integrated facility combined with numerical simulation

AbstractIn this study, an integrated measurement and control facility with an airfoil weir as the primary overcurrent structure is proposed by considering the flow characteristics over different shapes of weir trough facilities as well as the approach of merging measurement and control functions. The incomplete self‐similarity theory and dimensional analysis are used to derive the stage‐discharge relationship. The hydraulic characteristics of the facility under different shape‐related parameters, weir crest heights (rotation angles), and flows are studied by combining model testing and numerical simulation. The findings demonstrate that changes in shape‐ related parameters and rotation angle do not affect the linear relationship between the water depths in the critical and reference sections. The mean error in the discharge formula derived by dimensional analysis is 2%. The Froude number is less than 0.25 under all the working conditions. From the backwater height and head loss, it can be seen that the larger the P/C (the maximum airfoil thickness P to the chord length C ratio) value of the facility under the premise of unifying the weir crest height, the better the overflow capacity. When the height of the weir crest is 0.3778 m, the negative pressure on the surface of the airfoil weir increases with increasing P/C value.

COVID-19-Related Risk Factors for Developing Occupational Contact Dermatitis Along With Its Incidence, Prevention, and Management: A Systematic Review.

Occupational contact dermatitis (OCD) is an eczematous local inflammatory skin irritation caused by repeated use of hand sanitizer and other chemical substances. Occupational irritant contact dermatitis (OICD) and occupational allergic contact dermatitis (OACD) are the two variants of CD that cannot be identified clinically. Hand dermatitis (HD) is typically assessed as a clinical consequence because it affects the hands most frequently at work as per epidemiological studies on OCD. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 standards were followed when conducting this umbrella review. We used the search terms "Occupational Contact Dermatitis AND COVID-19" to search forthe most pertinent papers in full text on the databasesPubMed/MedLine, ScienceDirect, and PubMed Central (PMC). Additionally, the reference section of the papers was used to find more articles. A total of 11,646results were found, and eight papers remained after applying the inclusion criteria (full-text papers, English language, studies published in the previous 10 years, involving humans, and only systematic reviews). After completing the title and abstract screening, we obtained five papers. Next, the full-text screening and AMSTAR quality check were completed, yielding the same five papers. After searching ScienceDirect, five papers that met the inclusion criteria were included, and six papers were selected from the references, yielding a total of 11 papers. The causes of occupational dermatitis from protective face masks are discussed in this review. We anticipate an increase in the incidence of occupational dermatitis linked to face mask use given that a large segment of healthcare workers (HCWs) wear protective face masks. To understand the prevalence and available therapies for mask-related occupational dermatitis, further well-designed research is required.

Biochronostratigraphy and palaeobiogeography of Echioceratidae (Ammonitina) from the Raricostatum Zone (Aplanatum Subzone) in NW Iberia

This paper examines the uppermost Sinemurian and lowermost Pliensbachian ammonite fauna recorded in NW Iberia with a special focus on Echioceratidae from the Aplanatum Subzone. In total, 852 specimens have been collected bed-by-bed from five reference sections from the Asturian, Basque-Cantabrian, and Lusitanian basins. Echioceratidae, namely Paltechioceras genus, represent 86.2% of the sample, Polymorphitidae (Leptonotoceras genus) the 10%, and less than 4% of the specimens are Eoderoceratidae, Phricodoceratidae, or Oxynoticeratidae. This study describes five species of Paltechioceras, namely P. tardecrescens, P. oosteri, P. recticostatum, P. elicitum, and P. romanicum. They allow a biochronostratigraphic division for the studied basins and its worldwide correlation. One of the species, P. romanicum, is the latest one registered in all the studied sections, occurring directly below the Sinemurian–Pliensbachian boundary. The disappearance of this widely distributed species marks the echioceratids extinction. This work reviews the global events described around the Sinemurian–Pliensbachian transition (the Sinemurian–Pliensbachian boundary event). Finally, we present a palaeobiogeographical analysis of the Paltechioceras species described, giving more information to discuss the opening of the Hispanic Corridor during the late Sinemurian.

Evaluation of Minimum Axial Airway Area and Airway Volume in Orthognathic Surgery Patients.

The aim of this study was to compare preoperative and postoperative linear, planar, and volumetric measurements in the pharyngeal airway in orthognathic surgery patients. Preoperative and postoperative cone beam computed tomography (CBCT) images of 60 patients, who underwent maxillary advancement with mandibular setback (Group I, n=25) and bimaxillary advancement (Group II, n=35), were compared. The airway was divided into 3 regions as nasopharynx, oropharynx, and hypopharynx. Linear and planar measurements were made on the reference sections of each region. The minimum axial airway area, the volume of 3 regions, and total airway volume were also measured. Regarding the linear, planar, and volumetric measurements, while there was a statistically significant increase in the measurements for all three regions in Group II, in Group I only the measurements in the nasopharyngeal region demonstrated a statistically significant increase postoperatively ( P <0.05). There was an increase in minimum axial airway areas in both groups; however, it was only statistically significant in Group II ( P <0.05). There was a statistically significant increase in total airway volumes in both groups ( P <0.05). A positive and good correlation was found between the percent increase in the minimum axial area and the percent increase in the total volume ( P <0.05). While bimaxillary advancement surgery results in a significant increase in the pharyngeal airway, mandibular setback with maxillary advancement caused an increase in the total airway. Changes that may occur in the airway should be considered while planning orthognathic surgery.

Flexural Behavior of Galvanized Iron Based Cold-Formed Steel Back-to-Back Built-Up Beams at Elevated Temperatures

Cold-formed steel (CFS) sections have become popular in construction due to several advantages over structural steel. However, research on the performance of galvanized iron (GI)-based CFS under high temperatures, especially regarding its flexural behavior, has been limited. This study extensively investigates how GI-based CFS beams with varying spans behave under elevated temperatures and subsequent cooling using air and water. This study examines the impact of temperature loading and compares the effectiveness of air- and water-cooling methods. Experimental results are validated and analyzed alongside findings from finite element modeling (FEM) using ABAQUS (2019_09_13-23.19.31) and the Direct Strength Method (DSM). Additionally, this study conducts a parametric investigation to assess how beam span influences flexural capacity. Among beams heated to the same temperature, those cooled with water show slightly lower load capacities compared to those cooled with air. The highest load capacity observed is 64.3 kN for the reference specimen, while the lowest is 26.2 kN for the specimen heated for 90 min and cooled with water, a 59.27% difference between them. Stiffness decreases as heating duration increases, with the reference section exhibiting significantly higher stiffness compared to the section heated for 90 min and cooled with water, with a 92.76% difference in stiffness. As heating duration increases, ductility also increases. Various failure modes are observed based on different heating and cooling conditions across different beam spans. This study provides insights into how GI-based CFS beams perform under temperature stress and different cooling scenarios, contributing valuable data for structural design and safety considerations in construction.

Fundamental Barriers to Green Energy Production in Selected EU Countries

Most EU countries are trying to develop new sources of energy to meet local power requirements due to energy shortages. The most popular renewable energy developments include biogas stations, wind turbines, water turbines, and solar systems. This article focuses on reviewing studies concerning the utilization of solar energy systems, especially photovoltaic (PV) ones, in European countries such as Germany, Italy, Spain, and Poland, which are leaders in PV installations. The review identifies factors influencing the development of PV investments and the energy situation in these countries. Economic, market, environmental, and infrastructural barriers, as well as driving factors, are presented. In all countries, the majority of installations were in the prosumer sector, with only a very small percentage in the state-owned sector. The methodology of the study covered the mentioned barriers, which were identified using scientific databases such as Scopus, Web of Science, and branch organizations websites like the International Renewable Energy Agency (IRENA). The novelty of the article lies in its examination of special barriers concerning green energy production in chosen EU countries. Normally, when reading articles on PV installations, as presented in the References section, one primarily observes a description of the construction process without deep involvement in the presented ideas.

Reference Section of the Сampanian Stage of the Southwestern Crimea: Problems of Substage Subdivision and Global Correlation

Reference Section of the Сampanian Stage of the Southwestern Crimea: Problems of Substage Subdivision and Global Correlation

New insight on upper Silurian-lowermost Devonian conodont biostratigraphy of the Argentine Precordillera and its palaeogeographic implications for the SW Gondwana margin

ABSTRACT The Cerro del Fuerte section, located in the Central Precordillera of San Juan Province, is considered a reference section to the study of Silurian-Devonian conodont biostratigraphy from Argentina and South America. The conodont association recovered in this section comprises twenty-five conodont taxa (species and sub-species) belonging to ten genera which allowed to record six conodont biozones from the Ludlow, Pridoli, and the Early Devonian (Lochkovian). Based on this new conodont biostratigraphy we propose constraining the brachiopod biostratigraphy reported in the same section. The Lau Event is probably recorded in the middle levels of the Los Espejos Formation where a change in the conodont fauna is verified. Despite that during the late Silurian and Early Devonian, the Argentina Precordillera was located at high southern latitudes in southwest Gondwana, the conodont fauna studied are composed of geographically widespread taxa supporting that the late Silurian – early Devonian was a time interval with minimal conodont provincialism.

Carbonate-siliciclastic deposits of the Lower Uk Subformation (Neoproterozoic) in the stratotype section and its correlation within Bashkirian Mega-Anticlinorium of the Southern Urals

Research subject. Carbonate-siliciclastic deposits of the Lower Uk Subformation were thoroughly studied in the section along the Yuryuzan river (near Ust-Katav town, Chelyabinsk region) and correlated with subformation sections along the Basu, Zilim and Bolshoy Inzer rivers. Material and methods. A detailed description of the stratotype section was carried out; sandstones, siltstones and limestones were studied in thin sections. The sections were correlated with each other. Results. Relationships between the Lower Uk Subformation and the underlying deposits are studied. The petrographic characteristics of rocks are presented. The Lower Uk Subformation sequences are traced between sections of various structural-tectonic zones of the Bashkirian Mega-anticlinorium (BMA). Conclusions. The set of features supports the idea about the presence of a sedimentary hiatus at the base of the formation, even in the most complete sequences (which contain the locally developed Shubino Member of the Minyar Formation). In the stratotype and in other reference sections, the Lower Uk Subformation has a pronounced three-membered structure; it is subdivided into the lower (siliciclastic) Yamashta, middle (substantially carbonate) Akkostyak, and upper (siliciclastic-carbonate) Avdyrdak members. The lithofacies analysis results suggest a change in environments from coastal-marine siliciclastic to shallow-marine siliciclastic-carbonate (middle and inner ramps) due to fluctuations in the relative sea level and, probably, climate change. It was established that the area of the Suleimanovo anticline at latest Riphean corresponded to the distal sedimentary environments in comparison with the southern and western zones (Alatau anticlinorium) of the BMA.

СLIMATIC AND PHYTOCENOTIC EVENTS OF THE LATE PLEISTOCENE (MIS 5-MIS 3) AT THE SOUTHEASTERN COAST OF THE GULF OF FINLAND

The paper analyses a debatable issue concerning the ranking of climatic-stratigraphic units within two marine isotope stages (MIS) - MIS 5 and MIS 4. Palynological records from the Mikulino interglacial sections of the northwestern Russian Plain which are most critical for correlations are reviewed. A representative series of numerical dates obtained by the IR-OSL method, and detailed palynological records enabled a detailed climatic-chronostratigraphic division of the Late Pleistocene sequence of the Voka reference section on the southeastern coast of the Gulf of Finland. The representative palynological spectra provide strong evidence of a warm interval of interglacial rank in the latter half of MIS 5, corresponding to the standard M6, M7, and M8 Mikulino palynozones. Additionally, they highlight a period of significant cooling during MIS 4, characterized by the dominance of periglacial vegetation formations in the study area. This challenges the viewpoint of the extensive Kalinin glaciation during that time, believed to have spread many hundreds of kilometers south of the Gulf of Finland. Data for MIS 3 reveal a two-fold alternation of interstadial and stadial (periglacial) climate intervals during the period between 39 ka and 33 ka.For the first time, detailed reconstructions and datings of climate-phytocenotic successions of paleoclimatic events approximately between 100 ka and 30 ka have been provided for the territory of the East European Plain (and Northern Eurasia as a whole). These events correspond to the latter half of MIS 5, MIS 4, and an interval between 39 ka and 33 ka during MIS 3.