Distribution pattern of the Ordovician black shale constrained by graptolite zonation in the western margin of the Ordos Block, North-West China

The graptolitic shale from the late Middle to early Late Ordovician along the western margin of the Ordos Block is a good target bed for shale gas exploration. The horizontal well Zhongping-1 drilled by the Changqing Oilfield Company in 2019 produces a daily gas output of 6.42Ã104 m3 and has proved the tremendous potential for shale gas exploration on the west margin of the Ordos Block. However, strong heterogeneity of total organic carbon (TOC), thickness, porosity and other parameters of the black shale have been revealed at different levels and localities. Therefore, a study of graptolite zonation, aiming to illustrate and predict the temporal and spatial distribution of the black shale in high resolution, is essential for shale gas exploration. A total of four wells were investigated carefully during the summer of 2022 and 102 samples were collected for the identification of graptolites. The well Qitan-9, the northernmost of the studied wells, is located in the Ordos Etok Banner, Inner Mongolia Autonomous Region. The graptolite faunas can be assigned into two biozones, the Pterograptus elegans Biozone and the Jiangxigraptus vagus Biozone. The latter is correlated with the Didymograptus murchisoni Biozone. The base of the J. vagus Biozone is defined at the first appearance datum (FAD) of J. vagus at the depth of 4741.42 m. The well Ren-16 is located in the Etok Front Banner, Inner Mongolia Autonomous Region. The Nemagraptus gracilis was found at the depth of 2880.06 m. Additionally, graptolites Pseudazygograptus incurvus, Cryptograptus tricornis and Reteograptus geinitzianus were collected from the level of 2881.93 m, showing also the characteristics of the N. gracilis Biozone. The boundary between the N. gracilis Biozone and J. vagus Biozone is tentatively placed at the depth of 2881.93 m. The well Li-105 is located in the Yanchi County, Wuzhong City, Ningxia Hui Autonomous Region. Graptolites are well preserved in this drill core. Some of them are preserved in 3D or half relief. N. gracilis was found at the depth of 4262.60 m while Climacograptus bicornis appears first 5.19 m above this depth. Accordingly, the base of C. bicornis Biozone is placed at the FAD of C. bicornis at the depth of 4257.41 m. The well Yintan-2, the southernmost of the studied wells, is located in the Huanxian County, Gansu Province. According to the graptolite fauna, two biozones can be distinguished, the Climaocograptus bicornis Biozone and the Nemagraptus gracilis Biozone. The boundary between these biozones is placed at the FAD of C. bicornis, i.e. at the depth of 3866.82 m. The spatial and temporal distribution of the black shale, as constrained from the graptolite zonation, shows that the black shale is strongly diachronous, getting younger southwards along the western margin of the Ordos Block. The base of black shale is diachronous from the P. elegansBiozone in well Qitan-9 to the J. vagus Biozone in well Ren-16 and the N. gracilis Biozone in wells Li-105 and Yintan-2. The top of the black shale is also diachronous from the J. vagus Biozone in the well Qitan-9 to the N. gracilis Biozone in the well Ren-16 and C. bicornis Biozone in the wells Li-105 and Yintan-2. The temporal and spatial distribution pattern of the black shale in the Ordos Region of North China shows that the sedimentary facies change from north to south and the depocenter has migrated southwards. This pattern differs significantly from the results of some former studies showing facies belts were being distributed westwards from the platform to shallow shelf, and further on to deep shelf and slope-basin. The distribution pattern of the black shale supports the hypothesis that the Alxa oldland thrust southwards is the driving force for southward migration of the depocenter during the foreland basin evolution process. Neither the peripheral foreland basin associated with the Ordovician arc-land collision event in the North Qinling orogenic belt nor the rift basin hypothesis is consistent with this pattern. The black shale distribution pattern as constrained from the graptolite zonation calls for a reconsideration of the tectonographic and palaeogeographic properties of the western margin of the Ordos Block

The Xiaoyangqiao section, Dayangcha, North China: the new global Auxiliary Boundary Stratotype Section and Point (ASSP) for the base of the Ordovician System

In 2019 the Sub-Commission on the Ordovician System approved the Xiaoyangqiao section, North China as a new ASSP section for the base of the Ordovician System. The sedimentary succession of the section is exposed in a natural outcrop near the Dayangcha Village at a position of 42°3'24''N, 126°42'21''E. It has a well-preserved, abundant and diverse fossil record across the boundary with key markers (conodonts and graptolites), which provide improved intercontinental correlation of the Cambrian– Ordovician boundary. The appearance of the first planktonic graptolites is immediately below the base of the Cordylodus lindstromi Conodont Zone. Other fossils, including acritarchs, brachiopods and trilobites are also present in the Xiaoyangqiao ASSP section. Non-biotic secondary global markers near the base of the Ordovician System include a positive carbon isotopic excursion with the maximum peak (named HSS) below the boundary, a prominent unnamed negative peak immediately below the boundary and a prominent carbon isotope excursion with positive peaks above the boundary. The latter excursion is associated with the appearance of the planktonic graptolites in the Ordovician. The strength of the Xiaoyangqiao ASSP section is the correlation between the conodonts and graptolites, correspondence of sea-level lowstands, and the matches of geochemical parameters

Upper Ordovician (Hirnantian) to Lower Silurian (Telychian, Llandovery) graptolite biostratigraphy of the Tielugou section, Shennongjia anticline, Hubei Province, China

The Tielugou section, Shennongjia Anticline, Hubei Province (China) includes a relatively complete succession of Hirnantian (latest Ordovician) to basal Telychian (Llandovery, early Silurian) graptolite faunas. The section shows the first record of a fauna of the late Aeronian Stimulograptus halli Biozone from South China, even though the index species was not reported. The Stimulograptus sedgwickii Biozone may not be represented, indicating a possible gap at the base of the Stimulograptus halli Biozone. The interval yields a number of taxa that are elsewhere reported to originate only in the Stimulograptus halli Biozone. The youngest graptolitic levels are included in the Spirograptus guerichi Biozone based on specimens of Parapetalolithus dignus and Parapetalolithus palmeus not known from earlier intervals. Spirograptus guerichi is not represented in the section. The Tielugou section provides the first detailed information on the faunas and thickness of the encountered biostratigraphic units for the Shennongija region

Numerical analysis of the dynamic evolution of mining-induced stresses and fractures in multilayered rock strata using continuum-based discrete element methods

In this study, the continuum-based discrete element method (CDEM) was adopted to simulate the evolution of mining-induced stress and fracturing during roadway tunnelling and mining in multilayered heterogeneous rock strata. The CDEM integrates the finite element method (FEM) and the discrete element method (DEM) to characterize the mining-induced stress evolution, the discontinuous fractures, separations, and caving that occur in the interfaces between multilayered rock strata. The maximum tensile-stress criterion and the Mohr-Coulomb strength criterion were used to evaluate the tensile and shear failure of the material elements. The CDEM model for rock strata was constructed by employing image processing and reconstruction approaches, using the geometrical and physical parameters that were measured from a real coal mining site. The stress evolution and compression deformation of the roof and floor strata were computed to evaluate the criticality of mining-induced disasters. The constructed model was employed to simulate and analyse the immediate roof collapse, immediate floor bulges, and the compaction of the collapse blocks, as well as the large deformation, separation, and collapse between the immediate roof and the main roof during coal seam mining. It was shown that the proposed method could predict ranges for the caving zone and fracture zone in the rock roofs that were in good agreement with the observation results from the real coal mining site

Supplementing Oregano Essential Oil in a Reduced-Protein Diet Improves Growth Performance and Nutrient Digestibility by Modulating Intestinal Bacteria, Intestinal Morphology, and Antioxidative Capacity of Growing-Finishing Pigs

This study investigated the effects of supplementing oregano essential oil (OEO) to a reduced-protein diet on growth performance, nutrient digestibility, intestinal bacteria, intestinal morphology, and antioxidative capacity of growing-finishing pigs. Forty-eight barrows were randomly allotted to four treatments including normal-protein diet (NPD), reduced-protein, amino acid-supplemented diet (RPD), the same RPD supplemented with chlortetracycline (RPA), and RPD supplemented with OEO (RPO). The data showed that dietary OEO supplementation increased the average daily gain of pigs compared with NPD and RPD. The gain:feed in RPO- and NPD-fed pigs was higher than those in RPD- and RPA-fed pigs. Increased average daily feed intake and 10th-rib backfat thickness were detected in RPA-fed pigs. Pigs fed the RPO had higher apparent total tract digestibility (ATTD) of crude protein than those fed the other diets. The RPD and RPA treatments showed reduced counts of Lactobacillus spp. in ileal digesta of pigs. The RPA and RPO treatments also showed lower Escherichia coli counts in ileal digesta than the NPD and RPD treatments. Dietary OEO supplementation increased villous height of the jejunum and the ileal and plasma total antioxidative capacity of pigs. In conclusion, dietary OEO supplementation could improve the growth performance and nutrient digestibility of pigs by modulating intestinal bacteria, intestinal morphology, and antioxidative capacity

First report of a Late Triassic dinosaur track from the Zigui Basin, Middle Yangtze region, China.

International audienceTrace fossils offer a great potential to enhance our understanding of the rise of dinosaurs and their interactions with the environment. Here, we report a Rhaetian theropod footprint found in the Shazhenxi Formation of the Zigui Basin, representing the stratigraphically oldest dinosaur track recorded from the Middle Yangtze region and has great significance for understanding the Late Triassic theropods and their distribution across East Asia. The tridactyl track is assigned to cf. Eubrontes isp. and shows a similar morphology with some tracks from the Sichuan Basin, indicating that Eubrontes had a wider spatial distribution in the Upper Triassic than previously thought. This work highlights the great interest and importance of palaeoichnological prospecting in the Triassic deposits of the Zigui Basin

Effect of oregano essential oil and benzoic acid supplementation to a low-protein diet on meat quality, fatty acid composition, and lipid stability of longissimus thoracis muscle in pigs

Abstract Background Consumers are becoming increasingly interested in food containing appropriately high concentration of intramuscular fat (IMF) and polyunsaturated fatty acids (PUFA). The supplementation of feed with antioxidants decreases degradation of lipids in muscles thereby enhances nutritional and sensory properties of meat. Two experiments were conducted to determine the effects of adding oregano essential oil (OEO) and benzoic acid (BA) to low-protein, amino acid-supplemented diets on meat quality, sensory profile, fatty acid composition, and lipid oxidation of longissimus thoracis (LT) muscle in pigs. Methods In Exp. 1, 21 barrows were housed in metabolism cages and randomly allotted to 1 of 3 diets. The three diets were normal protein diet (NPD), medium protein diet (MPD) and low protein diet (LPD) with 1% and 2% less than NPD, respectively. In Exp. 2, 36 barrows were randomly divided into three experimental groups, namely, NPD, LPD, and identical LPD supplemented with blends of OEO (250 mg/kg feed) and BA (1000 mg/kg feed) (LPOB) groups. Results No significant effects of diets on meat quality were observed in Exp. 1. The b*45min, tenderness, and IMF content in LPD muscle were higher than those in NPD and LPOB muscle. The LT muscle in LPD group contained a higher percentage of oleic acid (C18:1n-9) and a lower percentage of linoleic acid (C18:2n-6) than those in NPD group. Dietary LPOB improved oxidative stability, total superoxide dismutase, and glutathione peroxidase but decreased drip loss in LT muscle. Conclusions These findings suggest that growing-finishing pigs fed with a low-protein, amino acid-supplemented diet show a high content of intramuscular fat in the longissimus thoracis muscle. Dietary LPOB enhances the anti-oxidative status by improving antioxidative capacity but deteriorates the sensory attributes by decreasing IMF content of meat

Induced neural stem cells suppressed neuroinflammation by inhibiting the microglial pyroptotic pathway in intracerebral hemorrhage rats

Summary: Intracerebral hemorrhage usually manifests as strong neuroinflammation and neurological deficits. There is an urgent need to explore effective methods for the treatment of intracerebral hemorrhage. The therapeutic effect and the possible mechanism of induced neural stem cell transplantation in an intracerebral hemorrhage rat model are still unclear. Our results showed that transplantation of induced neural stem cells could improve neurological deficits by inhibiting inflammation in an intracerebral hemorrhage rat model. Additionally, induced neural stem cell treatment could effectively suppress microglial pyroptosis, which might occur through inhibiting the NF-κB signaling pathway. Induced neural stem cells could also regulate the polarization of microglia and promote the transition of microglia from pro-inflammatory phenotypes to anti-inflammatory phenotypes to exert their anti-inflammatory effects. Overall, induced neural stem cells may be a promising tool for the treatment of intracerebral hemorrhage and other neuroinflammatory diseases