Hydrocarbon migration mechanism into a reservoir is one of the most controversial in oil and gas geology. The research aimed to study the effect of supercritical carbon dioxide (СО2) on the permeability of sedimentary rocks (carbonates, argillite, oil shale), which was assessed by the yield of chloroform extracts and gas permeability (carbonate, argillite) before and after the treatment of rocks with supercritical СО2. An increase in the permeability of dense potentially oil-source rocks has been noted, which is explained by the dissolution of carbonates to bicarbonates due to the high chemical activity of supercritical СО2 and water dissolved in it. Similarly, in geological processes, the introduction of deep supercritical fluid into sedimentary rocks can increase the permeability and, possibly, the porosity of rocks, which will facilitate the primary migration of hydrocarbons and improve the reservoir properties of the rocks. The considered mechanism of hydrocarbon migration in the flow of deep supercritical fluid makes it possible to revise the time and duration of the formation of gas–oil deposits decreasingly, as well as to explain features in the formation of various sources of hydrocarbons and observed inflow of oil into operating and exhausted wells.

During the Upper Ordovician–Lower Silurian, chert was widely distributed in the Zhongbao Formation in the eastern part of the North Qilian Orogen. The origin and the tectonic setting of these chert were largely unknown. In order to analyse the material provenance, sedimentary environment, their formation and the tectonic setting, we present petrology and geochemical research on chert samples collected from Shihuigou Section. The evidence provided by radiolarite occurrences, Aluminium (Al)–iron (Fe)–manganese diagram and the silicon(Si)/Si + Al + Fe + calcium ratios suggesting a non-hydrothermal input and the biogenic origin chert. The geochemical features and the petrographic signatures have shown that the chert was also influenced by a terrigenous origin. It is considered that the deposition of the Late Ordovician chert is mainly affected by tectonic collision and volcanic ash events. During the Late Ordovician–Early Silurian transition, huge amounts of volcanic ash were released by massive volcanic activity that fell into the ocean, triggering the proliferation of radiolarians. Finally, in the Late Ordovician–Lower Silurian the tectonic setting of the North Qilian Orogen was not a typical deep-water basin, nor a typical continental margin, but a multi-island deep-water basin, which is closed to the mainland.

Pareiasaurs were globally distributed, abundant, herbivorous parareptiles with the basal-most members found only in the mid-Permian of South Africa. These basal forms form a monophyletic group and were locally abundant and became extinct at the top of the Tapinocephalus Assemblage Zone at the end of the Guadalupian. Four species of basal pareiasaurs are currently recognised: Bradysaurus baini, B. seeleyi, Embrithosaurus schwarzi and Nochelesaurus alexanderi, but they are all poorly understood and there remains historic uncertainty as to their validity. In this paper, our second contribution designed to improve understanding of the basal group, we present the first detailed cranial description and updated diagnosis for Nochelesaurus alexanderi and demonstrate that it is a distinct taxon based on one cranial autapomorphy, a large transversely wide postparietal, and a combination of cranial characters. Within the local group of mid-Permian pareiasaurs, we recognise new dental features of Nochelesaurus alexanderi: non-symmetrical marginal cusp arrangements on upper and lower teeth resulting from an extra basal mesial cusp; an incipient horizontal cingulum on lower jaw teeth, sometimes with one or two tiny medial cingular cusps; and up to ten marginal cusps. Our study demonstrates that tooth morphology and orientation, cranial ornamentation, morphology of the cheek bosses, shape of the postfrontal and postparietal, and morphology of the distal paroccipital process of the opisthotic are the most useful to identify South African mid-Permian pareiasaurs.

Antibiotic residues have entered into the environment owing to the unreasonable use and disposal of antibiotics. The emergence of antibiotic resistance poses a huge threat to ecosystems and human health. In this study, the network analysis method was used to compare publications on antibiotics in water, soil and sediment from the aspects of countries, institutes, journals, subject categories and keywords based on Web of Science Core Collection. The results indicated that the United States of America and China had dominant positions of studies on antibiotics. The Chinese Academy of Sciences published the most articles on antibiotic research. ‘Chemosphere’, ‘Science of the Total Environment’, ‘Environmental Science and Technology’ and ‘Applied and Environmental Microbiology’ all appeared in the top six journals. ‘Environmental Sciences and Ecology’ was the core subject category of antibiotic research. Further analysis results depicted that ‘Antibiotics’, ‘Tetracycline’ and ‘Antibiotic Resistance’ were found as the research hotspots. Tetracycline and oxytetracycline all showed in the top 50 keywords of antibiotics research in water, soil and sediment. However, chlortetracycline, sulfadiazine and tylosin all emerged only in the top 50 keywords of antibiotics study in soil. In future, more attention should be paid to antibiotic resistance genes and antibiotic resistance bacteria in antibiotics research.