Bryozoans represent a dominant faunal element in the Lower Permian of Western Australia. Here, three new trepostome species are described from the Callytharra Formation (Sakmarian – Artinskian): Nikiforopora haigi sp. nov., Iraidina dendroidea sp. nov., and I. multicava sp. nov. The genera Nikiforopora and Iraidina were previously unknown from the Permian deposits of Australia. The genera have no contemporary equivalents from other areas, so their use for stratigraphic correlation and palaeobiogeography remains limited. Intensive studies of the Permian Bryozoa from Australia appear necessary to better understand the Gondwanan distributions of the genera and species.

A new representative of the roachoid family Necymylacridae (stem group Dictyoptera) and associated vegetation with insect interactions from the Shanxi Formation (lower Permian), China

The Shawan Sag and its adjacent areas are rich in hydrocarbon resources. Moreover, the genesis and evolution patterns of zeolite cements in the sandy conglomerate reservoirs have resulted in diverse types of reservoir spaces, a complex composition, and significant heterogeneity. To investigate their impact on reservoir quality, this study integrates core observations, thin-section petrography, scanning electron microscopy (SEM), whole-rock X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) for macro–micro comparative analysis of zeolite cement types, formation mechanisms, and pore systems in the Lower Permian strata of the Shawan Sag and adjacent areas. Research demonstrates that provenance exerts a control on type and origin of the diagenetic zeolites: In the Shawan Sag, zeolites form through hydration of volcanic glass in tuff, while adjacent areas develop zeolites via albitization of plagioclase derived from andesite. This genetic divergence drives pore differentiation: Zeolite (heulandite and laumontite) evolution in the Sag generates grain-edge fractures through cement volume shrinkage and crystalline water release. In contrast, the adjacent areas exhibit reservoir spaces dominated by dissolution pores, resulting from the dissolution of laumontite and calcite, along with a relatively higher overall rock porosity.

Terrestrial tetrapods originated during the Middle Devonian, and the group rapidly diversified throughout the subsequent Carboniferous and Permian periods. Feeding in air rather than water is expected to require changes to tetrapod mandibular form and function. Previous biomechanical studies on jaw evolution, however, found that the increase in functional disparity lagged behind terrestrialisation by approximately 70 Myr, coinciding with the origin of amniotes and herbivory. We expand on a previous dataset composed primarily of non-amniote tetrapods to identify the drivers of this diversification, including representatives of all major amniote clades from the Permo-Carboniferous. First, we measured nine biomechanical traits from 111 tetrapod jaws in medial view. Second, we performed an Elliptical Fourier Analysis on 198 jaws in lateral view and 73 jaws in occlusal view. The first peak in jaw disparity, during the Pennsylvanian, occurs in carnivorous non-amniote tetrapods. However, the jaws of amniotes, particularly those inferred as herbivorous, are consistently more disparate than non-amniote tetrapods from the early Permian, especially in terms of jaw depth, symphysial length and force transmission. Functional and shape disparity of Palaeozoic tetrapod jaws follow a similar pattern that is explained by large-scale faunal turnovers and ecosystem structures.

Analysis of pyrobitumen in reservoirs can yield key information about hydrocarbon evolution, which may provide vital insights for deep- to ultra-deep hydrocarbon exploration in high- to over-mature petroliferous deep basins. The Ediacaran Dengying Formation in the Penglai area of the Sichuan Basin contains large-scale gas reservoirs, where pyrobitumen is extensively present. To understand the hydrocarbon accumulation and alteration processes in these reservoirs, in this study, we systematically investigated the characteristics of the reservoir pyrobitumen using detailed petrographic analysis and laser Raman spectroscopy. The results indicated that four types of reservoir pyrobitumen are present: pyrobitumen with isotropic (type I), mosaic (type II), fibrous (type III), and honeycomb (type IV) textures. Pyrobitumen in the dolomite reservoirs of the Deng 2 and Deng 4 members of the Dengying Formation often co-occurs with hydrothermal minerals, including saddle dolomite, quartz, and fluorite. The equivalent vitrinite reflectance (Rmc Ro%) calculated indicated that the pyrobitumen is over-mature, with Rmc Ro% values ranging from 3.46% to 3.89%. In addition, significant differences were observed in the Raman parameters between the four types of pyrobitumen: type IV shows the greatest degree of structural ordering, while type II exhibits the highest level of disordering, with types I and III exhibiting intermediate structural ordering. Finally, the spatial distribution of the four types of pyrobitumen indicated that hydrothermal pulses driven by the Emeishan Large Igneous Province toward the end of the Permian Period may be primarily responsible for the extensive cracking of paleo-oil pools, causing the development of types II–IV pyrobitumen and gas generation.

Determining the timing of hidden faults that terminate beneath the subsurface remains a significant challenge. For this contribution, seismic fault interpretation, fracture diagenesis analysis, and U-Pb dating of fracture cements are integrated to constrain the activity of hidden thrust faults in the southeastern Sichuan Basin. The results show that the EW- and NW-trending hidden thrust faults developed in the Permian, while the NE-trending faults have inherited later fault activity till the Cenozoic. The hidden thrust fault propagates upward from the top of the Upper Permian to the Lower Triassic strata. Fault inversion within the Permian is firstly identified by the thickness variation between the two fault walls. Core-based fracture diagenesis analysis indicates that multiple fractures and associated dissolution porosity developed within the tight matrix reservoir. In situ U-Pb dating of fracture cements yields ages of 247.4 ± 2 Ma and 234.8 ± 9.1 Ma, indicating that the hidden fault activity predates the Early Triassic. The absence of strata, evidence of structural uplift, and fault inversion collectively suggest that the first faulting in the eastern Sichuan Basin occurred at the end of the Middle Permian. The findings highlight that fracture–cave reservoir along the hidden thrust fault zone has been controlled by the coupling of the fracturing and karstification at the end of the Middle Permian, and is the key target for high gas production.

Organic pores serve as crucial storage spaces for shale gas, whose morphology and structure vary significantly among different types of organic matter, directly influencing the storage and seepage capacity of shale gas. The Upper Permian shale in the Western Hubei Trough formed in diverse sedimentary facies and has undergone multiple geological activities, resulting in strong heterogeneity of organic pores across different strata and regions. To figure out the heterogeneous characteristics of organic pores and the forming reason, the occurrence state of organic matter, pore morphology, and structural parameters (pore size, specific surface area, pore volume, and fractal dimension) of the Upper Permian shale in Western Hubei, have been discussed in detail, based on the data of field emission scanning electron microscopy and low-temperature nitrogen adsorption experiments conducted on the extracted organic matter. On this basis, fractal dimension theory was applied to discuss the heterogeneity of organic pores in different layers, and the reason for heterogeneity has been analyzed in detail. The results indicate that the occurrence mode of organic matter in different layers presents various characteristics: in the Gufeng Formation, the organic matters distribute primarily dispersed in flocculent state; at the bottom of Wujiaping Formation, they occur as isolated individuals, while the organic matters turn into discontinuous laminated distribution in the middle and upper Wujiaping Formation; in the Dalong Formation, the organic matters show continuous parallel banded distribution. Moreover, the morphology and structural parameters of organic pores exhibit obvious changes from the Gufeng Formation to the Dalong Formation: (a) the pore morphology shows the changed trend as extremely complex-simple-complex; (b) the specific surface area and pore volume follow the trend as large-small-large; (c) the pore size distribution displays in the pattern of bimodal-unimodal-bimodal; (d) the data of fractal dimension show the variation of high–low–high. Overall, the various sedimentary environments during the Upper Permian shale depositional period determined the differences in organic sources, which dominated the heterogeneity of organic pores in shale. These data clarify the development and variation characteristics of organic matter pores under different depositional environments, providing a theoretical basis for shale gas exploration and development during the transition from marine to marine–continental facies.

The present paper describes stoneflies Vyazonemoura storozhenkoi gen. et sp. nov. of the Palaeonemouridae family from the Upper Permian (Severodvinian Stage, Vyazovka Formation) locality of Vyazovka, Orenburg Region, Russia. The peculiar structure of the very narrow Vyazonemoura wing and some similarities in venation with Triassic stoneflies are discussed.

Cherts, as chemical sedimentary formations, serve as repositories of historical evolutionary data encompassing paleotectonics, paleogeography, and paleoclimate. Furthermore, they play a crucial role as geological foundations for oil and gas exploration. In the Upper Yangtze region, the origin and underlying genesis mechanisms of unstratified cherts from the Permian period have been subject to ongoing debate. This study employs lithological analyses including outcrop profiles and thin-section observations alongside geochemical analyses of macronutrients, trace elements, and rare earth elements to investigate the depositional environment of laminated cherts from the Permian era. Additionally explored are the siliciclastic origins of non-laminated cherts and the diagenetic mechanisms at play in this area. The findings indicate that stratified chert in the Middle and Upper Yangtze regions originate from basin sedimentation below the carbonate compensation depth interface while unstratified chert primarily form through dissolution of carbonates attributable to both hydrothermal activity and seawater processes. This comprehensive investigation provides a robust geological foundation for oil and gas exploration within this study area while also serving as a valuable reference for future research on studies related to chert.

Lithofacial analysis of carbonate rocks of the Upper Carboniferous and Lower Permian in the stratotypic section of the Usolka showed the presence of several types of sediments differing in composition and mechanism of formation. Background sediments include fine grained limestones – wackstones with radiolarians and sponge spicules of LFT1, LTF2, and LTF3 lithofacies and their dolomitized and phosphatized differences. They indicate the quietness and depth of the sedimentary basin in this zone of the Preuralian foredeep. The sediments with introduced components include granular limestones – grainstones and rudstones LTF4 with fragments of reef fauna and calcareous siltstones LFT5 with tuff (ash) material. The intermediate type of precipitation is dark gray pelitic clay-siliceous-carbonate deposits – marls and argillites or mudstones LTF6. They contain background siliceous-carbonate mud with an admixture of introduced clay material. The irregular alternation of these types of sediments in the Usolka section indicates the conditions of the slope of a deep-sea basin into which clastic and volcanogenic ash material was pulsed. The main removal of carbonate fragments in the rudstones and grainstones of LTF4 occurred as a result of earthquakes from the reef zone bordering the western side of the Preuralian foredeep. The facies environment corresponds to the area of transition from the deep-sea shelf of the western part of the Preuralian foredeep to the central zone of the basin.

Spectroscopic and SEM-EDS studies of gymnosperm wood from the Upper Permian Tacuary Formation, Paraguay

This study presents a comprehensive geochemical investigation of the undeveloped Pb-Zn mineral deposits in the My Duc area of Quang Binh Province, central Vietnam. The regional geology includes the upper Silurian to lower Devonian Dai Giang Formation (limestone, mudstone, sandstone, and schist), the upper Devonian Co Bai Formation, the lower Carboniferous La Khe Formation (limestone), and the upper Carboniferous to lower Permian Muong Long Formation (recrystallized limestone), with Cretaceous lamprophyre intrusions. The Pb-Zn ore bodies are primarily hosted in dolomitized and recrystallized limestone and are classified into primary and oxidized zones. The main ore minerals are sphalerite, galena, smithsonite, and associated sulfide and carbonate minerals. A total of 31 rock and ore samples were collected from ore bodies and surrounding rocks, followed by X-ray diffraction (XRD), electron probe micro analysis (EPMA), and chemical analyses. Sphalerite from Dong Tri Mountain shows high Zn contents (64.5-67.7 wt.%), low Fe, and moderate Cd concentrations, indicating high purity. The average Zn and Pb concentrations in ore bodies were 1,230 ppm and 27,700 ppm, respectively, with Zn reaching up to 16,000 ppm in high-grade ores. Geochemical anomalies of Cd, Sb, As, and Ag were also detected. Additionally, a regional geochemical survey was conducted over an area of 180 km<sup>2</sup>, using 90 stream sediment and 90 heavy mineral samples. Anomalous zones were identified near the Tau A and Len Dong Areas, where multielement enrichment indicates hydrothermal vein-type mineralization. These zones are considered promising targets for future exploration. The findings suggest that the My Duc Pb- Zn deposits exhibit strong geochemical signatures typical of epithermal processes, and further trenching, drilling, and geophysical surveys are recommended to define economically viable ore zones.

For more than a century there has been controversy as to the circumstances during the Carboniferous and Permian periods which made flight possible for giant dragonflies. Higher air density and elevated oxygen levels have been suggested, however, increased metabolic rates would lead to heat-exchange problems. Recently, Alan E. R. Cannell concluded from engineering investigations that higher air density, in the range 1.5-1.6 bar, would aid in thermal regulation, which would as well enhance flight aerodynamics. Contrary to plate tectonics, my new indivisible geoscience paradigm, Whole-Earth Decompression Dynamics, leads in a logical, causally-related manner to higher air density during the time giant dragonflies flourished. Even within the limitations of these simple calculations, the results suggest that during the Carboniferous and Permian periods only about half of the surface area comprising deep-ocean basins had opened.

Abstract Numerous oligochaete cocoons, previously interpreted as cladoceran crustaceans, are described from the upper Permian (Lopingian) freshwater Karaungir Lagerstätte in eastern Kazakhstan. The cocoons appear as small, wrinkled, ovoid capsules, prolonged into a neck at one pole and a long slender stalk at the other; both extensions are covered with minute ridges forming a striated pattern. By their size range and distinct (although limited) morphological features, the cocoons are identical to those of the extant freshwater genus Rhynchelmis Hoffmeister, 1843 (Oligochaeta: Lumbriculidae) and thus represent the oldest undoubted record of the Clitellata. We interpret Archedaphnia Smirnov, 1970 (= Propleuroxus Smirnov, 1970, n. syn.) as a genus for fossil microdrile oligochaete cocoons similar to those of Rhynchelmis, and synonymize all five species described in Archedaphnia and Propleuroxus under Archedaphnia kazakhstanica Smirnov, 1970 sensu lato.

Northern Xinjiang, China, hosts globally recognized Carboniferous–Permian super basins with abundant hydrocarbon resources. However, previous research has predominantly focused on the northwestern region, while the eastern part, despite its significant exploration potential, remains underexplored. Guided by the exploration concept of the “Northern Xinjiang Megalake”, this study investigates key basins in eastern Northern Xinjiang, including the eastern Junggar Basin, Santanghu Basin, and Turpan–Hami Basin. Results indicate that the Lucaogou Formation in the Santanghu Basin and the Pingdiquan Formation in the Junggar Basin share similar characteristics. Both represent good to excellent source rocks dominated by Type II 1 kerogen, currently at the mature stage, with high hydrocarbon generation potential and significant shale oil prospects. Their organic matter is primarily derived from microbial-algal sources, especially Tasmanites and algal mats, with low contributions from higher plants, and deposited under anoxic, slightly brackish to saline conditions. In contrast, the Taodonggou Group in the Turpan-Hami Basin comprises medium to very good quality source rocks, with mixed Type II 1 –III kerogen, also in the mature stage, capable of generating both oil and gas. The organic matter has a complex origin, with contributions from both microbial-algal communities and higher plants, and was deposited in relatively lower salinity waters. Marine source rocks of the Shiqiantan Formation in the Junggar Basin are of medium to very good quality, dominated by Type III kerogen, and are also in the mature stage. Their organic matter is mainly sourced from higher plants, indicating gas-prone characteristics. This study provides the first systematic comparison of source rocks across these basins, offering valuable insights into regional hydrocarbon exploration, as well as into the mechanisms of organic matter enrichment and source rock development in the Carboniferous–Permian systems of Northern Xinjiang.

ABSTRACT Tetrapod footprints are abundant and morphologically diverse throughout the Permian. However, the morphological similarities among ichnogenera often lead to misidentification or taxonomic confusion. In this study, we reanalysed eight slabs from the Rio do Rasto Formation (upper Permian) of southern Brazil, previously attributed to Dicynodontipus penugnu, Procolophonichnium isp. and Rhynchosauroides gangresci. Through detailed examination of dactyl morphology, gradial structure, digit proportions, and the relative position of digit V, we reinterpret these footprints as belonging to the ichnospecies Batrachichnus salamandroides and Procolophonichnium nopcsai. Additionally, a newly analysed specimen is described here for the first time and assigned to the ichnospecies B. salamandroides. These findings extend the temporal range of these ichnogenera into the Wuchiapingian, providing new insights into the palaeoecology and evolutionary history of late Permian tetrapods. urn:lsid:zoobank.org:pub:230854F1-B0BC-4713-B77D-1C5219EC7656

ABSTRACT Traditional models suggest that the final closure of the Paleo-Asian Ocean (PAO) occurred during the Late Permian to Triassic. However, the timing of the closure remains a topic of considerable debate. The widespread distribution of A-type granites dating from the Carboniferous to Permian periods indicates that closure may have occurred earlier, potentially as far back as the Late Carboniferous to Early Permian or even the Late Devonian. The granitoids with ages from the Late Carboniferous to Early Permian in northeastern Erenhot, within the Xing’an-Mongolian Orogenic Belt (XMOB), offer insightful perspectives on the complicated tectonic history related to the eventual closure of the PAO. By studying zircon U-Pb ages, Hf isotopic composition, and whole-rock geochemical composition of granitoids from the Zhunsujihua Granitic Belt (ZGB) and Baolage Granitic Belt (BGB) in northeastern Erenhot, we aim to gain a better understanding of their petrogenesis and tectonic settings while also constraining the closure time of the PAO. Zircon U-Pb ages of the ZGB and BGB granitoids span from 288 to 317 Ma and from 275 to 295 Ma, respectively. These granitoids have compositional ranges of 70.16–78.04 wt% SiO2, 3.73–5.02 wt% K2O, and 10.48–15.65 wt% Al2O3, and show light rare earth element (LREE) enrichment and negative Eu anomalies. The ZGB alkali-feldspar granite exhibits adakitic characteristics, whereas other ZGB granitoids show I-type features. The BGB granitoids display A-type signatures. Zircon εHf(t) values vary from + 10.05 to + 15.48, with young two-stage Hf model ages (TDM2) spanning from 332 to 656 Ma, suggesting that both the ZGB and BGB granitoids have originated from partial melting of juvenile crustal materials. These findings suggest that the granitoids formed during the transition from subduction to post-collisional extension, which implies that the PAO in the northeastern region of Erenhot had closed at the latest by the Early Permian.

Martínez Catalán et al. (2024) present a comprehensive review of the origin of both observed and hypothetical arcuate structures located within the European and North African segments of the Variscan belt. They conclude that all studied arcs are secondary in nature, having formed during the mid to late Carboniferous and early Permian periods (330–290 Ma). These arcs developed through a combination of several mechanisms, operating over different time intervals, with varying significance across the arcs. The main mechanisms include transcurrent shearing and rigid-plastic indentation, aligning with a combination of the dextral mega-shear model proposed by Martínez Catalán et al. (2007) and the indenter model previously suggested by Julivert and Arboleya (1984), Sánchez-García et al. (2003), and others.

ABSTRACTThermal history of the subsea permafrost in the sedimentary section of the Rusanovskaya‐2 well in the South Kara sedimentary basin has been numerically reconstructed using the ICE2020 software package, which is a part of the GALO flat basin modeling system. The thermal evolution of the sedimentary section during the last 3.5 My is considered as a final stage of the basin evolution, which began with continental rifting in the Upper Permian. The basin history of the last 3.5 My included repeated periods of sea transgressions and regressions. The thickness of permafrost could decrease to 30–40 m during the transgressions and increase to 300–600 m in the time of the sea regressions. The simulation results suggest that the thickness of permafrost increased during the last period of maximum cooling, reaching a maximal depth of 312 m about 14.5 Ky. After that, the permafrost degraded in response to marine transgression and climate warming. The depth of the base of current permafrost is estimated to be 152 m, and the permafrost is degrading from below at a rate of about 12 m/1000 years.

The Zhina coalfield in Guizhou Province possesses substantialcoalbedmethane (CBM) resources. The Upper Permian Longtan Formation featuresmultiple thin coal seams with well-developed cleats and microfractures,while the overlying coal seams display complex coal-body characteristics.Wellbore instability issues, such as spalling and collapse, are particularlypronounced during drilling operations within the upper coal-bearingformations. A plugging-type solid-free drilling fluid system can enhancethe wellbore stability and mitigate coal seam damage. This study employedX-ray diffraction (XRD), scanning electron microscopy (SEM), hydrationstability, and mechanical property tests on coal seam and adjacentstrata cores from the Zhangjiawan block of the Zhina coalfield toelucidate potential reservoir damage mechanisms in CBM drilling. Tominimize fluid loss and enhance sealing, a fluid loss reducer andviscosifier, AMSN, were developed. AMSN, with a relative molecularmass of 4.81 × 106, forms a three-dimensional spatialnetwork structure in solution, characterized by circular or hexagonalconfigurations. At a concentration of 300 mg/L, the AMSN solutionexhibits a significant increase in apparent viscosity accompaniedby the formation of numerous structural entities. The AMSN solutiondemonstrates excellent thermal resistance, effective plugging capability,and lubricity, maintaining an apparent viscosity retention rate above47% at 95 °C. Sand bed plugging tests indicate a filtration volumeof 0 mL at 3 min. The friction coefficient of the 0.3% AMSN solutionwas reduced to 13.2 N/m2. Based on the developed AMSN,the plugging agent and antiwater blocking agent were optimized, anda plugging-type solid-free drilling fluid system was formulated. Thissystem exhibits superior rheological properties, plugging capacity,and reservoir protection performance. Field application results demonstratethat the drilling fluid system effectively reduces wellbore enlargementin collapse-prone upper coal seams, thereby enhancing the wellborestability and improving the cementing quality of the CBM wells.