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Deep coalbed methane (CBM) resources are abundant in China, and in the last few years, the country's search for and extraction of CBM have intensified, progressively moving from shallow to deep strata and from high-rank coal to medium- and low-rank coal. On the other hand, little is known about the gas content features of deep coal reservoirs in the eastern Junggar Basin, especially with regard to the gas content and the factors that affect it. Based on data from CBM drilling, logging, and seismic surveys, this study focuses on the gas content of Baijiahai Uplift's primary Jurassic coal seams through experiments on the microscopic components of coal, industrial analysis, isothermal adsorption, low-temperature CO2, low-temperature N2, and high-pressure mercury injection. A systematic investigation of the controlling factors, including the depth, thickness, and quality of the coal seam and pore structure; tectonics; and lithology and thickness of the roof, was conducted. The results indicate that the Xishanyao Formation in the Baijiahai Uplift usually has a larger gas content than that in the Badaowan Formation, with the Xishanyao Formation showing that free gas and adsorbed gas coexist, while the Badaowan Formation primarily consists of adsorbed gas. The coal seams in the Baijiahai Uplift are generally deep and thick, and the coal samples from the Xishanyao and Badawan formations have a high vitrinite content, which contributes to their strong gas generation capacity. Additionally, low moisture and ash contents enhance the adsorption capacity of the coal seams, facilitating the storage of CBM. The pore-specific surface area of the coal samples is primarily provided by micropores, which is beneficial for CBM adsorption. Furthermore, a fault connecting the Carboniferous and Permian systems (C-P) developed in the northeastern part of the Baijiahai Uplift allows gas to migrate into the Xishanyao and Badaowan formations, resulting in a higher gas content in the coal seams. The roof lithology is predominantly mudstone with significant thickness, effectively reducing the dissipation of coalbed methane and promoting its accumulation. [ABSTRACT FROM AUTHOR]

Abstract Pterosaurs were the first vertebrates to evolve active flight. The lack of many well-preserved pterosaur fossils limits our understanding of the functional anatomy and behavior of these flight pioneers, particularly from their early history (Triassic to Middle Jurassic). Here we describe in detail the osteology of an exceptionally preserved Middle Jurassic pterosaur, the holotype of Dearc sgiathanach from the Isle of Skye, Scotland. We identify new autapomorphies of the flight apparatus (humerus and sternum), which further support the distinctiveness of Dearc compared with other early-diverging pterosaurs and describe features, such as the vertebral morphology, shared with later-diverging pterosaurs that probably developed convergently to support a large body size or as a sign of modular evolution. We used extant phylogenetic bracketing to infer the principal cranial and antebrachial musculature, indicating that Dearc had large and anteriorly placed palatal musculature that compensated for weak temporal jaw adductors and wing musculature suggestive of flight style reliant on powerful adduction and protraction of the humerus. Comparisons with other pterosaurs revealed that non-pterodactyloids such as Dearc, despite their overall conservative bauplans, adapted various flight and feeding styles. The osteology and myology of Dearc are indicative of a large predator that flew and hunted above lagoons and nearshore environments of the Middle Jurassic.

Hydrogen sulphide (H2S) concentrations across three adjacent gas condensate fields in Southwestern Gissar produced from fractured Middle-Upper Jurassic reef-carbonates with anhydrite-bearing beds have been analysed. Wellsite testing measurements followed by iodometric titration showed concentrations of H2S below 0.2 mole%. Statistical analyses and cross plots of H2S vs. depth, reservoir temperature, porosity, anhydrite content, well tests and water saturation did not reveal linear correlations. Uniform gas condensate compositions and constant souring levels through time rule out secondary bacterial or/and technogenic processes, while temperatures bellow 90–110°С are against thermochemical sources. Low H2S values could result from mineral-fluid interactions within the host rock. However, low abundance of H2S and carbon dioxide (CO2) (

Foreland basins are rich in oil and gas resources, with most being concentrated in the foredeep zone. However, as breakthroughs in oil and gas exploration in post-uplift basins have been made, these types of basins gradually become a research hotspot. The hinterland of the Junggar Basin is a post-uplift basin, and the Jurassic Sangonghe Formation is an important oil and gas-bearing layer in this area. However, there is still a significant debate about the types of sedimentary facies in this formation. With the progress of exploration and the continuous enrichment of geological data, the types and evolution of the sedimentary facies in the Sangonghe Formation have gradually become clearer. To clarify the sedimentary facies types, distribution, and the differences from the foredeep zone in the post-uplift basins of the foreland basin system, the study analyzed geological profiles, cores, well logging, seismic data, and analytical test results. It provided a detailed analysis of the sedimentary facies types, distribution characteristics, and controlling factors of the Sangonghe Formation. The sedimentary facies types of the Sangonghe Formation include braided river delta facies, sublacustrine fan facies, and lacustrine facies. The braided river delta facies are further subdivided into the plain and front subfacies, which are mainly distributed in the Shixi and Mobei areas. The sublacustrine fan facies are mainly distributed in the west sag of well 1 in the basin, characterized by Bouma sequences, with "A" and "B" segments being mostly common. The sediment source for these fans came from the braided river delta in the eastern part of the study area. During the sedimentary period of the Sangonghe Formation, there were three sources in the study area, instead of only two sources from the northwest and northeast as previously believed. Stable heavy mineral analysis showed that the W36 sublacustrine fan was affected by the northeastern sediment source, while the W46 sublacustrine fan was affected by the southeastern source. Sediments in the foredeep zone of the foreland basin were coarse, with simple sedimentary facies types and structural oil and gas reservoirs as the primary trap types. However, sediments in the post-uplift basin had finer grain sizes, with more varied sedimentary facies types, and were dominated by tectonic-lithologic and lithologic oil and gas reservoirs.

Although China has abundant lacustrine shale oil resources, their exploitation is challenging. Investigating the various occurrence states of shale oil in shale reservoirs provides value for the exploration and development of shale oil resources. With the shale in the second submember of Da'anzhai Member of Jurassic Ziliujing Formation of the central Sichuan Basin (the Da2 submember) as the research object, the study reveals the occurrence modes of shale oil under different states in various medium pores, through the implementation of the multi-temperature pyrolysis experiment, the observation of pore development characteristics under the scanning electron microscope and the analysis of the pore size distribution before and after oil washing. In the Da2 submember, the shale oil is mainly in the free state (0.42 to 10.88 mg/g), followed by the adsorption state (0.30 to 1.95 mg/g), as revealed by thermal simulation recovery. The reservoir space of shale includes organic pores (pore size: 2 to 600 nm), pyrite intergranular pores (pore size: 10 to 700 nm), shell pores (pore size: 20 to 1 000 nm), quartz/feldspar intergranular pores (pore size: 4 to 500 nm) and clay mineral intergranular pores (pore size: 4 to 500 nm). After oil washing, the results of nitrogen adsorption and high pressure mercury injection demonstrated a significant increase in pores with sizes of 2 to 30 nm and 60 to 1 000 nm, where most of shale oil is stored. Meanwhile, it was demonstrated that the shale oil in the Da2 submember mainly occurs in organic matter and pyrite by establishing a heat map of the relationship between the occurrence state of shale oil and the medium in the rock. Lastly, by fitting the content of shale oil in different occurrence states with the oil volume obtained before and after oil washing, the pore size range for shale oil accumulation in the study area was determined. The free state of shale oil in the Da2 submember primarily accumulates in pores of organic matter and pyrite with pore size of 60 to 700 nm, and the adsorbed state of shale oil mainly accumulates in the organic matter pores with pore size of 2 to 6 nm. In conclusion, this study presents a thorough examination of the occurrence characteristics of shale oil in Da2 submember, and it will support shale oil exploitation efforts in the area.

To further reveal the development characteristics of Jurassic source rocks in the southwest depression of the Tarim Basin and their paleoenvironments, with the aim of guiding future shale oil exploration and development, the study integrated rock pyrolysis, maceral analysis, inorganic geochemistry, biomarker compounds, and carbon isotope analyzes.It explored the development characteristics and organic matter enrichment patterns of coal-bearing mudstones from the Lower Jurassic Kangsu Formation and mudstones and silty mudstones from the Middle Jurassic Yangye Formation in the Kekeya area of the southwest depression, Tarim Basin. The results showed that the total organic carbon (TOC) content in the source rocks of the Kangsu and Yangye formations was relatively higher, ranging from 1.7% to 63.5% (with an average of 24.4%), and 0.6% to 6.9% (with an average of 2.1%), respectively, indicating source rocks of good to excellent quality. Source rocks from both formations exhibited low maturity, being in the low-maturity to mature stage.In addition, carbon isotope analysis of kerogen, thin section observations, and biomarker compound analysis indicated that the parent material of the organic matter in the coal-bearing mudstones of the Kangsu Formation and the lower section of the Yangye Formation mainly derived from higher terrestrial plants, while the silty mudstones of the upper section of the Yangye Formation contained abundant planktonic algae. During the depositional period of the Kangsu Formation, the paleoclimate was warm and humid, and the water environment was freshwater, with suboxic and slightly oxidizing conditions. In the early depositional stages of the Yangye Formation, the paleoclimate was also hot and humid, and the depositional environment was similar to that of the Kangsu Formation, characterized by freshwater and suboxic conditions. With the gradual rise in lake level in the late depositional period of the Yangye Formation, the paleoenvironment transitioned to a brackish and suboxic environment. The hot and humid climate, coupled with increased salinity, was conducive to the reproduction of planktonic algae and other aquatic organisms, thereby affecting the organic matter supply in silty mudstones of the upper section of the Yangye Formation. Furthermore, the enhancement of water reducibility during this period was also beneficial for the preservation of organic matter. In summary, paleoclimate, paleosalinity, and depositional environment are important factors influencing the organic matter enrichment in the Jurassic lacustrine source rocks of the Kekeya area.

China's tight sandstone reservoirs possess immense hydrocarbon reserves with substantial development potential. Hydraulic fracturing in horizontal wells is a crucial enhancement method for developing these reservoirs. In tight sandstone reservoirs of the Jurassic Shaximiao Formation of the J gas field in the transitional zone between central and western Sichuan, differences in rock mechanical properties and geomechanical characteristics result in significant variations in fracturing effectiveness across wells despite similar fracturing processes. To enhance the effectiveness and specificity of fracturing, this study examined the impact of three geological factors—brittleness index, minimum horizontal principal stress, and differences between two horizontal principal stresses—on fracturing effectiveness. Based on the difference in horizontal principal stress, the geological conditions in the study area were classified into two categories, type Ⅰ and type Ⅱ, from favorable to less favorable. The influence of various engineering factors on fracturing effectiveness under these two types of geological conditions was analyzed, and optimal ranges for engineering parameters under these conditions were proposed. The Analytic Hierarchy Process (AHP) and Grey Relational Analysis (GRA) were employed to calculate the influence weight of each geological and engineering parameter on fracturing effectiveness, and then a quantitative evaluation model was established. Based on the correlation with fracturing effectiveness, the AHP-based model was selected as the optimal method to evaluate the fracturing effectiveness in the study area. It was also used to verify the rationality of the proposed ranges for engineering parameters outlined in the study and the applicability of the comprehensive evaluation model for fracturing effectiveness. This paper revealed significant differences in the suggested parameter ranges for horizontal well fracturing engineering under different geological conditions, with notably broader ranges for wells in more favorable conditions than those in less favorable ones. The AHP-based model was identified as the optimal geological and engineering comprehensive evaluation model for assessing the fracturing effectiveness in the study area.

The imbibition law of the Jurassic continental shale in Fuxing area is not clear， which brings great challenges to the production test after well shut-in. In addition， studies on the imbibition law and influencing factors of continental shale are insufficient. Therefore， the experiment on the imbibition law of the Jurassic continental shale in Fuxing area was conducted based on the low-field nuclear magnetic resonance （NMR）. First， the differences in physical properties of shale of Lianggaoshan Formation and Dongyuemiao Member in Ziliujing Formation were tested and analyzed. Then， the changes in permeability and porosity before and after the imbibition were set as the evaluation indexes， and the influences of lithology， fluid， fluid pressure， and clay content on the imbibition law of the continental shale were analyzed. Besides， the wettability of the continental shale was evaluated. The experimental results show that compared with that of Dongyuemiao Member， the average porosity of shale of Lianggaoshan Formation is smaller， and the average permeability is larger； the average brittle mineral content is higher， and the average clay mineral content is lower. During the imbibition process of the Jurassic continental shale in Fuxing area， micro-fractures are induced by clay hydration， which provides additional imbibition channels. However， the imbibition ability of limestone is weaker than that of shale， and there are no micro-fractures during the imbibition； in addition， the shell limestone interlayer in the reservoir may inhibit the imbibition and micro-fracture propagation in the shale. The oil phase will enhance the micro-fracture propagation after the shale induces micro-fractures in the aqueous phase， and the complicated oil-water phase imbibition may be beneficial to the permeability improvement in the shale reservoir. Compared with atmospheric imbibition， pressureed imbibition has a limited effect on inducing micro-fractures and improving permeability， and the imbibition rate is larger； the imbibition equilibrium is earlier， but the imbibition amount is smaller. The influence of confining pressure on imbibition should be considered during well shut-in. The micro-fractures induced by hydration in shale with high clay mineral content are more significant， and the effect of improving permeability is more obvious. The imbibition rate and imbibition amount of shale in the oil phase are smaller than those in the aqueous phase， and the wettability of shale is hydrophilic. The experiment reveals the imbibition law and the characteristics of micro-fractures induced by the hydration of the Jurassic continental shale in Fuxing area， which provides a theoretical basis for the well shut-in and production test of continental shale during flowback.

Abstract Switzerland is an ichthyosaur country: it has a rich record of marine reptile fossils, particularly the fish-shaped ichthyosaurs, and the according research. Here, we provide an overview over the 12 or more genera and at least 13 species plus numerous fragmentary remains of ichthyosaurs from the Triassic to the Cretaceous that have been discovered in twelve cantons thus far, of which four species are based on Swiss holotypes. This wealth of ichthyosaur species can be explained by their abundance in the Middle Triassic conservation deposits (Konservat Lagerstätte) of Monte San Giorgio, as well as occasional discoveries in strata of Middle Triassic to Early Cretaceous age. The moderate abundance of outcrops in reasonable conditions in combination with the long history of palaeontological research in Switzerland explains this good fossil record. In addition to this unique overview, we provide more data for further studies and update the knowledge of these taxa.

Copyright of Petroleum Geology & Experiment is the property of Petroleum Geology & Experiment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Experiment is the property of Petroleum Geology & Experiment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Experiment is the property of Petroleum Geology & Experiment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Experiment is the property of Petroleum Geology & Experiment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The superorder Forcipulatacea is a major clade of sea stars with approximately 400 extant species across three orders (Forcipulatida, Brisingida, Zorocallida). Over the past century, the systematics of Forcipulatacea have undergone multiple revisions by various authors, with some considering numerous families such as Asteriidae, Zoroasteridae, Pedicellasteridae, Stichasteridae, Heliasteridae, Labidiasteridae, and Neomorphasteridae, while others recognized only two families (i.e., Asteriidae and Zoroasteridae). Recent molecular analyses have shown the artificial nature of some of these groupings. Notably, four well-supported clades (Zorocallida, Brisingida, Stichasteridae, and Asteriidae) emerged from a synthesis of morphological and molecular evidence. The majority of extinct forcipulatacean species have been placed in modern families. However, many of these fossil species are in need of revision, especially those species placed within the Asteriidae, the largest of all forcipulatacean families. Methods: In light of recent advancements in forcipulatacean systematics, we comprehensively reassess six well-preserved Jurassic forcipulatacean taxa, including the earliest crown-group members from the Hettangian (∼201.4 Ma), and also describe two new Jurassic genera, Forbesasterias gen. nov. and Marbleaster gen. nov. We assembled the largest and most comprehensive phylogenetic matrix for this group, sampling 42 fossil and extant forcipulatacean species for 120 morphological characters. To infer phylogenetic relationships and construct an evolutionary timeline for the diversification of major clades, we conducted a Bayesian tip-dating analysis incorporating the fossilized birth-death process. A total of 13 fossil species were sampled in our analysis, including six taxonomically revaluated herein, two recently reappraised species from the Jurassic, and five additional species from the Cretaceous and Miocene. Results: Contrary to prior assumptions, our results indicate that none of the Jurassic taxa investigated belong to Asteriidae or any other modern families, and instead represent stem-forcipulatids. Furthermore, our phylogenetic results suggest that Asteriidae likely originated during the late Cretaceous. Our findings highlight a greater early diversity within the Forcipulatacea than previously presumed, challenging existing perceptions of the evolutionary history of this significant clade of marine invertebrates. [ABSTRACT FROM AUTHOR]

A causal mechanism for the Volgian Isotopic Carbon Excursion (VOICE) remains enigmatic. Elemental geochemical profiles of the Deer Bay Formation, Sverdrup Basin, Arctic Canada that record the VOICE and contemporaneous strata are herein examined to provide insight into depositional environments during Late Jurassic‐Early Cretaceous time. Silver (Ag) and Cadmium (Cd) are enriched across the VOICE at localities on Axel Heiberg Island, and in Tithonian (∼Volgian) strata of Ellef Ringnes Island. Other redox‐sensitive trace elements do not exhibit spatially or temporally consistent patterns and indicate oxic conditions. A lack of relationship across the VOICE between Ag and the quality, quantity, and isotopic composition of organic matter suggests that the negative isotope excursion and interval of Ag enrichment are not merely functions of changes in organic matter source or amount, while a lack of spatially consistent change in geochemical indices of weathering similarly excludes climate change and/or sediment provenance as a driver. Therefore, in a ventilated setting and without marked changes in organic matter content, Ag enrichment may be due to hydrothermal activity. Contemporaneous Ag enrichment in strata from Svalbard suggests that a source of hot fluid sufficient to produce Ag‐rich seawater may have been related to rifting in the adjacent proto‐Amerasia Basin. Hydrothermal activity may also have been a widespread source of isotopically depleted carbon. This work develops new geochemical fingerprints that may be used to trace the spatial extent of hydrothermal events that do not leave an extinction pattern but may nonetheless have a far‐reaching influence on biogeochemical systems. Plain Language Summary: Silver (Ag) is enriched in marine sedimentary strata of Tithonian age, and in particular, across the Volgian Isotopic Carbon Excursion in Arctic Canada. However, other redox‐sensitive trace elements do not exhibit spatially or temporally consistent patterns, and collectively suggest oxygenated conditions near the seafloor during this time. Contemporaneous Ag enrichment in strata from Svalbard suggests that a source of hot fluid sufficient to produce Ag‐rich seawater may have been related to rifting in the adjacent proto‐Amerasia Basin. Hydrothermal activity may also have been a widespread source of isotopically depleted carbon. This work develops new geochemical fingerprints that may be used to trace the spatial extent of hydrothermal events that do not leave an extinction pattern but may nonetheless have a far‐reaching influence on biogeochemical systems. Key Points: Silver is enriched across the Volgian Isotopic Carbon Excursion (VOICE) in the Canadian ArcticOther redox‐sensitive trace elements do not exhibit spatially or temporally consistent patterns and indicate oxic conditionsRifting in the proto‐Amerasia Basin may have resulted in hydrothermal activity that caused the silver enrichment [ABSTRACT FROM AUTHOR]

New Mesozoic (Kimmeridgian to Albian) corals from northern Mexico (Mexican states Coahuila, Durango and Sonora), that were established by Imlay and Wells between 1940 and 1946, are revised on the basis of the type material kept at the Museum of Paleontology of the University of Michigan in Ann Arbor (Mich., USA). From the six new species, only one may remain in use, and the other five species are considered to be synonyms of older taxa. [ABSTRACT FROM AUTHOR]

Our revision of the type material of Liodesmus led to significant adjustments in our understanding of the taxon when the original type specimen of Pholidophorus gracilis, which was later determined as the type species of the genus Liodesmus, was recently found in the collection in Berlin. It had been confused with a specimen that was described as the type specimen of the species Liodesmus gracilis in the collection in Munich. Moreover, the Munich specimen was mistakenly considered by all authors who have studied Liodesmus as a type specimen for the genus Liodesmus. However, the original holotype of Pholidophorus gracilis and this Munich specimen of Liodesmus gracilis belong to two different families. Caturus brevicostatus, whose holotype was recently found in Berlin as well, is described in detail here for the first time. Liodesmus sprattiformis is now described under the new genus Nasrinsotoudehichthys outside Caturidae but within the Caturoidea. Since all specimens that have been described so far under Liodesmus either belong to other, previously described genera, belong to new genera clearly outside the description of the genus Liodesmus, or are nomina dubia (including the type species Pholidophorus gracilis), the genus Liodesmus and the Liodesmidae are nomina dubia as well. [ABSTRACT FROM AUTHOR]

Switzerland is an ichthyosaur country: it has a rich record of marine reptile fossils, particularly the fish-shaped ichthyosaurs, and the according research. Here, we provide an overview over the 12 or more genera and at least 13 species plus numerous fragmentary remains of ichthyosaurs from the Triassic to the Cretaceous that have been discovered in twelve cantons thus far, of which four species are based on Swiss holotypes. This wealth of ichthyosaur species can be explained by their abundance in the Middle Triassic conservation deposits (Konservat Lagerstätte) of Monte San Giorgio, as well as occasional discoveries in strata of Middle Triassic to Early Cretaceous age. The moderate abundance of outcrops in reasonable conditions in combination with the long history of palaeontological research in Switzerland explains this good fossil record. In addition to this unique overview, we provide more data for further studies and update the knowledge of these taxa. [ABSTRACT FROM AUTHOR]

Establishing the temporal sequence of the Middle-Late Jurassic Yanliao Biota is essential as it anchors the timing of many key evolutionary innovations in vertebrates. Lack of sufficiently reliable high-precision ages of fossil-bearing horizons hinders our ability to reconstruct the tempo and mode of vertebrate evolution. Here, we frame a temporal sequence of Yanliao Biota with precise age constraints for iconic vertebrates, proposing that the major vertebrate-bearing strata span from 164 Ma to 157 Ma in age. The increasing ecological diversity of mammaliaforms is well illustrated by the Middle-Late Jurassic Yanliao Biota and Early Cretaceous Jehol Biota. Incorporation of the updated temporal frameworks in Bayesian tip-dated mammaliaform phylogeny reveals that Triassic haramiyidans are separate from Jurassic taxa and unrelated to crown Mammalia. Tip-dated phylogeny supports a long-fuse model for mammal evolution, featured by a Late Triassic root and Middle-Late Jurassic interordinal diversification of crown Mammalia, showing consistency with molecular-based timetrees in divergence timing.

Yinlong downsi, the earliest known ceratopsian, is represented by dozens of specimens of different sizes collected from the Upper Jurassic of the Junggar Basin, northwestern China. Here, we present the first comprehensive study on the bone histology of Yinlong downsi based on ten specimens varying in size. Four ontogenetic stages are recognized: early juvenile, late juvenile, subadult, and adult. The reconstructed growth curve suggests that Yinlong may reach sexual maturity at 6 years old, which is earlier than that of the well-studied early-diverging ceratopsian Psittacosaurus (9 years old) but later than ceratopsids (about 3 to 5 years old). This may indicate that sexual maturity begins earlier during the evolution of ceratopsians, and that the giant size of ceratopsids is acquired by accelerating growth rates. The cortex of the tibia mainly consists of fibrolamellar bone tissues, but parallel-fibered bone and lines of arrested growth (LAGs) are very common throughout ontogeny, suggesting a moderate growth rate. Quantitative analysis indicates that Yinlong has a maximum growth rate similar to those of other small-sized dinosaurs such as Psittacosaurus, Dysalotosaurus, and Troodon, and their maximum growth rates are higher than those of extant squamates and crocodiles but lower than those of extant mammals and large dinosaurs. This suggests that body size plays a more important role in growth rate than other factors such as phylogenetic position and/or diet among non-avian dinosaurs.

As the first group of tetrapods to achieve powered flight, pterosaurs first appeared in the Late Triassic. They proliferated globally, and by the Late Jurassic through the Cretaceous, the majority of these taxa belonged to the clade Monofenestrata (which includes the well-known Pterodactyloidea as its major subclade), typified by their single undivided fenestra anterior to the orbit. Here, a new taxon Melkamter pateko gen. et sp. nov., represented by the specimen MPEF-PV 11530 (comprising a partial cranium and associated postcranial elements), is reported from the latest Early Jurassic (Toarcian) locality of Queso Rallado (Cañadón Asfalto Formation) and referred to the clade Monofenestrata, increasing our previously known taxonomic and geographic representations, and temporal range for this clade. This occurrence marks the oldest record of Monofenestrata globally and helps to shed critical light on the evolutionary processes undergone during the ‘non-pterodactyloid’-to-pterodactyloid transition within the Pterosauria. In addition, another single isolated tooth from the same locality shows ctenochasmatid affinities. These finds further elucidate the still-poor Gondwanan Jurassic pterosaur fossil record, underscoring that most of our current ideas about the timing and modes of pterosaur evolution during that period are largely based on (and biased by) the pterosaur fossil record of the Northern Hemisphere.

Abstract The Alborz Mountains in north Iran underwent several tectono-metamorphic events during opening and closure of the Palaeotethys and Neotethys Oceans. These events are recorded by rare and discontinuously exposed metamorphic rocks, such as the HP-LT Asalem-Shanderman Complex and the Gasht Metamorphic Complex (GMC), that are considered to have been metamorphosed during the closure of the Palaeotethys Ocean. The GMC comprises poorly exposed metasediments and amphibolites metamorphosed under greenschist- to amphibolite-facies conditions, along with smaller volumes of granites. Different dating methods were applied to selected samples of the GMC basement to constrain the geological evolution of this part of the Alborz Mountains. A metagranite yielded two LA-ICP-MS U–Pb zircon ages of 638.4 ± 4.1 Ma and 590.3 ± 4.8 Ma that possibly date protolith crystallisation and later deformation and metamorphism, respectively, and a granite yielded a late Ediacaran 551 ± 2.5 Ma U–Pb zircon crystallisation age. A northern provenance from the basement to the South Caspian Basin can neither be established nor ruled out because no age data are available for this unit. Derivation of the GMC from Turan Block basement is unlikely, as this has a different crustal makeup and is probably composed of Paleoproterozoic and early Neoproterozoic material. The zircon ages are similar to published ages from the Arabian-Nubian Shield, indicating that this part of the Alborz basement may have belonged to the northern margin of Gondwana in the Neoproterozoic before rifting and drifting away along with other Iranian blocks (the Cimmerian terranes) during opening of the Neotethys Ocean. Chemical Th-U-total Pb ages for metamorphic monazites from two metapelite samples yielded a very large range of spot ages, of which c. 80% falls between 200 and 250 Ma, that do not allow to distinguish between Eo-Cimmerian and Main Cimmerian events in the GMC. However, they may indicate that the amphibolite-facies peak metamorphism of the GMC occurred sometime in the Triassic, in any case much later than the Carboniferous metamorphism in the neighbouring Asalem-Shanderman Metamorphic Complex to the north. Peak-metamorphic amphibole from amphibolite, retrograde white mica and foliation-defining biotite from metapelites and magmatic white mica from granite yielded much younger 175.1 ± 0.5 to 177.0 ± 0.4 Ma 40Ar/39Ar plateau ages. The Toarcian 40Ar/39Ar ages for minerals with different nominal closure temperatures reflect very rapid cooling of GMC basement below the Shemshak Group due to extension-triggered uplift. This late Toarcian to Aalenian extension event can be correlated with the regional Mid-Cimmerian unconformity of mid-Bajocian age (c. 170 Ma) that resulted from the tectonic movements causing rapid uplift and erosion. Extension probably started in the western Alborz Mountains in the Toarcian, migrated eastward, and culminated in the Aalenian in the eastern Alborz with the formation of a deep-marine basin. It was probably triggered by the onset of the subduction of Neotethys oceanic crust beneath the Central Iranian Microcontinent.

Abstract The biology of extinct animals is usually reconstructed from external morphological characters and comparison with present-day analogues. Internal soft organs are very rarely preserved in fossils and require high-tech approaches for visualization. Here, we report the internal anatomy of a female and male of the ~ 162 Myr-old lobster Eryma ventrosum from the Jurassic La Voulte-sur-Rhône Konservat-Lagerstätte in France using X-ray synchrotron tomography. The Erymidae is an extinct, species-rich, widespread and ecologically important Mesozoic family of decapod crustaceans. Our investigation revealed the anatomy of the locomotory, respiratory, circulatory, excretory, digestive, nervous and sensory, and reproductive systems at a resolution resembling low-magnification histology. Particularly notable is the detailed preservation of the small brain and the fragile hepatopancreas, the main metabolic organ of decapods that decays rapidly post-mortem. The remarkable preservation shows that the internal anatomy of Eryma ventrosum is closer to that of Nephropidae (clawed lobsters) than Astacidae (freshwater crayfish), their closest living relatives based on skeletal morphology. The microanatomy of the gonads and hepatopancreas indicates that the two specimens investigated were a young, well-nourished female and male prior to sexual maturity. The analysis of the soft anatomy reveals remarkable conservatism over 160 Myr and offers new insights into feeding, reproduction, life history and lifestyle of an important component of the macrozoobenthos of Middle Jurassic seas.

Objective The good oil test results of Taiye 1 and Xingye L1 wells in the Jurassic Lianggaoshan Formation shale indicate the breakthrough of shale oil/gas exploration in the Jurassic continental shale in the Fuxing area of the eastern Sichuan Basin. To further clarify the oil/gas exploration potential and the organic matter enrichment mechanism of the Jurassic Lianggaoshan Formation shale, utilizing logging and core data of two typical wells Xingye X and Xingye Y, the whole-rock X-ray diffraction, organic carbon, major and trace elements were analyzed. Methods The Liang-2 lower submember was deposited in the environment of warm-wet (moderate weathering conditions) and freshwater, and there was no obvious difference in palaeoclimates of different unit formations. The La-Co data suggests a semi-deep to deep lake environment with a palaeowater depth ranging from 10.9 to 56.1 m; the anoxic reducing environment persisted on the lake floor despite the lake level fluctuation, but the palaeoproductivity was vertically increased. The shale interval is rich in sandy laminae, but the deposition rate of the shale layer is lower than that of the sandstone layer. Results According to the correlation analysis between sedimentary environment parameters and organic carbon content (TOC), the organic matter enrichment in the Liang-2 lower submember shale was mainly controlled by factors of palaeowater depth, palaeoredox environment, deposition rate, and palaeoproductivity, and slightly affected by the palaeosalinity and palaeoclimate conditions. The variation in the deposition environment resulted in the vertical heterogeneity of shale. Conclusion The shale facies of Unit 6, formed in the good conditions for the organic matter enrichment referring to an anoxic environment in deep water, with a low deposition rate, a high palaeoproductivity, and the slight influence of terrigenous sources, was a favorable target layer for exploration.

The morphology of stony corals (Scleractinia) remains the only means to reconstruct the most inclusive evolutionary history of the clade comprising both extant and extinct species. The definitions of morphological characters and their associated trait states are critical for assembling a dataset that could be analysed for phylogenetic reconstruction. Here, we present coral morphological data that consist of more than a hundred characters reviewed by the Corallosphere working group. These characters would eventually form the basis of a data matrix used to reconstruct the phylogeny of all extinct and extant scleractinian families. The initial results obtained by the working group comprise poorly resolved trees, which are biased by the complexity of the multiple character states and the multiplicity of researchers involved in the coding process. When the analysis is restricted to matrices consisting of families from the Triassic and Jurassic periods and coded by a single person, resolution increased, allowing for further exploration of various ingroups and outgroups. The results presented here represent analyses of (i) a data matrix with all families represented by their type genus; (ii) a data matrix with selected families represented by their solitary or phaceloid genera; (iii) a data matrix with only Triassic corals; (iv) a data matrix with only Jurassic corals; (v) a data matrix with Triassic and Jurassic corals; and (vi) data matrices with several outgroups. Well-resolved trees have been obtained in several cases. Phylogenetic rela-tionships among basal, robust and complex groups established using molecular data are discussed in the context of the morphological phylogeny obtained here.

The Alborz Mountains in north Iran underwent several tectono-metamorphic events during opening and closure of the Palaeotethys and Neotethys Oceans. These events are recorded by rare and discontinuously exposed metamorphic rocks, such as the HP-LT Asalem-Shanderman Complex and the Gasht Metamorphic Complex (GMC), that are considered to have been metamorphosed during the closure of the Palaeotethys Ocean. The GMC comprises poorly exposed metasediments and amphibolites metamorphosed under greenschist- to amphibolite-facies conditions, along with smaller volumes of granites. Different dating methods were applied to selected samples of the GMC basement to constrain the geological evolution of this part of the Alborz Mountains. A metagranite yielded two LA-ICP-MS U–Pb zircon ages of 638.4 ± 4.1 Ma and 590.3 ± 4.8 Ma that possibly date protolith crystallisation and later deformation and metamorphism, respectively, and a granite yielded a late Ediacaran 551 ± 2.5 Ma U–Pb zircon crystallisation age. A northern provenance from the basement to the South Caspian Basin can neither be established nor ruled out because no age data are available for this unit. Derivation of the GMC from Turan Block basement is unlikely, as this has a different crustal makeup and is probably composed of Paleoproterozoic and early Neoproterozoic material. The zircon ages are similar to published ages from the Arabian-Nubian Shield, indicating that this part of the Alborz basement may have belonged to the northern margin of Gondwana in the Neoproterozoic before rifting and drifting away along with other Iranian blocks (the Cimmerian terranes) during opening of the Neotethys Ocean. Chemical Th-U-total Pb ages for metamorphic monazites from two metapelite samples yielded a very large range of spot ages, of which c. 80% falls between 200 and 250 Ma, that do not allow to distinguish between Eo-Cimmerian and Main Cimmerian events in the GMC. However, they may indicate that the amphibolite-facies peak metamorphism of the GMC occurred sometime in the Triassic, in any case much later than the Carboniferous metamorphism in the neighbouring Asalem-Shanderman Metamorphic Complex to the north. Peak-metamorphic amphibole from amphibolite, retrograde white mica and foliation-defining biotite from metapelites and magmatic white mica from granite yielded much younger 175.1 ± 0.5 to 177.0 ± 0.4 Ma 40Ar/39Ar plateau ages. The Toarcian 40Ar/39Ar ages for minerals with different nominal closure temperatures reflect very rapid cooling of GMC basement below the Shemshak Group due to extension-triggered uplift. This late Toarcian to Aalenian extension event can be correlated with the regional Mid-Cimmerian unconformity of mid-Bajocian age (c. 170 Ma) that resulted from the tectonic movements causing rapid uplift and erosion. Extension probably started in the western Alborz Mountains in the Toarcian, migrated eastward, and culminated in the Aalenian in the eastern Alborz with the formation of a deep-marine basin. It was probably triggered by the onset of the subduction of Neotethys oceanic crust beneath the Central Iranian Microcontinent. [ABSTRACT FROM AUTHOR]

Enclosed ovules are a reproductive feature restricted to angiosperms. Although this feature can be used as a criterion for identifying fossil angiosperms, how ovules are enclosed and the nature of the placenta are still foci of debates. A reason underlying these controversies is the lack of reproductive organ fossils shedding light on these issues. These controversies hinder a clear understanding of angiosperm evolution and systematics. Here, we report a new fossil ovary, Xenofructus dabuensis gen. et sp. nov, from the Middle Jurassic of Liaoning, China. Our fossil clearly demonstrates the existence of ovules in Xenofructus that has a free central placentation. This new feature implies that a placenta in angiosperm gynoecia is homologous to an ovule/seed-bearing axis, and free central placentation is one of the early developed placentations. This discovery is apparently at odds with the current understanding of placentation and its evolution. Apparently, the understanding of angiosperms and their gynoecia should be updated with newly available palaeobotanical data. [ABSTRACT FROM AUTHOR]

The basal macronarian sauropod Europasaurus holgeri is known only from the Late Jurassic of the Langenberg Quarry near Goslar, Lower Saxony, Germany. Europasaurus has been identified as an insular dwarf and shows a clear resemblance to Camarasaurus and Giraffatitan. This study provides a detailed description of the dentition of Europasaurus based on an array of fossils outstanding in their abundance, variety of preservation, and ontogenetic range. Dental morphology for the replacement and functional dentitions, the tooth replacement pattern, and implications for food intake are described for the Europasaurus dentition, which is characterized by broad-crowned teeth. Characteristic features for Europasaurus are the presence of denticles on replacement teeth, the wrinkled enamel, and large wear facets both on the apex and on the carinae of the tooth crowns. The partially articulated skull SNHM-2207-R and isolated tooth rows DfmMh/FV 580.1 and DfmMh/FV 896.7 suggest the presence of strong connective tissue partially covering the teeth. This connective tissue would have provided stability and protection for the teeth. Evidence for this connective tissue include exposed tooth necks, in-situ teeth with strongly resorbed roots which no longer would have been connected to the jaw bone, and wrinkled enamel and its surface pattern. The same features can be observed in other sauropod taxa as well. We therefore suggest that eusauropods in general possessed this connective tissue structure, which may be an autapomorphy of the group. Possibly, this hypothetical structure is homologous to the rhamphotheca in birds and some non-avian theropods, which, however rarely, show such a close integration of keratinous tissue and teeth that we hypothesize here. [ABSTRACT FROM AUTHOR]

The biology of extinct animals is usually reconstructed from external morphological characters and comparison with present-day analogues. Internal soft organs are very rarely preserved in fossils and require high-tech approaches for visualization. Here, we report the internal anatomy of a female and male of the ~ 162 Myr-old lobster Eryma ventrosum from the Jurassic La Voulte-sur-Rhône Konservat-Lagerstätte in France using X-ray synchrotron tomography. The Erymidae is an extinct, species-rich, widespread and ecologically important Mesozoic family of decapod crustaceans. Our investigation revealed the anatomy of the locomotory, respiratory, circulatory, excretory, digestive, nervous and sensory, and reproductive systems at a resolution resembling low-magnification histology. Particularly notable is the detailed preservation of the small brain and the fragile hepatopancreas, the main metabolic organ of decapods that decays rapidly post-mortem. The remarkable preservation shows that the internal anatomy of Eryma ventrosum is closer to that of Nephropidae (clawed lobsters) than Astacidae (freshwater crayfish), their closest living relatives based on skeletal morphology. The microanatomy of the gonads and hepatopancreas indicates that the two specimens investigated were a young, well-nourished female and male prior to sexual maturity. The analysis of the soft anatomy reveals remarkable conservatism over 160 Myr and offers new insights into feeding, reproduction, life history and lifestyle of an important component of the macrozoobenthos of Middle Jurassic seas. [ABSTRACT FROM AUTHOR]

The Rhomaleosauridae were a clade of Jurassic plesiosaurians, characterized by triangular skulls, an elongated preorbital region, marked premaxillary-maxillary constriction, and intermediate body proportions that fall between pliosauromorphs and plesiosauromorphs. Despite recent progress in the study of dental replacement in plesiosaurians, the replacement features in rhomaleosaurids have not been studied yet. Here, the dental features of the rhomaleosaurid Maresaurus coccai Gasparini, 1997 are described and analyzed based on the holotype specimen. Regarding symmetry, it was determined that M. coccai shows symmetrical replacement in the maxillary-premaxillary and asymmetrical replacement in the dentary. Additionally, the tooth replacement cycle period (TRCP) of two alveoli was determined for the dental series, except for the anterior part of the left mandibular ramus, which presents an TRCP of three, an asymmetry considered here as teratology. This result indicates that the replacement cycle period (TRCP) of the two alveoli would correspond to a primitive character for Plesiosauria, displaying an increase of TRCP from two to three alveoli in taxa comparatively more derived within Pliosauridae. [ABSTRACT FROM AUTHOR]

The Aalenian–Bajocian (early Middle Jurassic) cooling event (ABCE) was a significant global climate disturbance during the Jurassic. Our analysis of sporopollen fossils from 18 mudstone and silty mudstone samples, collected from the lacustrine-terrestrial succession Xishanyao Formation in the Santanghu Basin, Northwest China, revealed a total of 191 species belonging to 53 genera. We identified an assemblage, the Cyathidites–Deltoidospora–Osmundacidites–Cycadopites assemblage, which dates to the Aalenian–Bajocian (early Middle Jurassic). This assemblage can be further divided into three subassemblages in stratigraphic order: the Cyathidites–Osmundacidites–Cycadopites subassemblage, the Cyathidites–Cycadopites–Psophosphaera subassemblage, and the Cyathidites–Deltoidospora–Osmundacidites subassemblage. We applied the Sporomorph EcoGroup (SEG) model to interpret the paleoclimate features. The sporopollen fossils indicate that the Santanghu Basin underwent a shift in vegetation types, from ground cover vegetation as the dominant form to canopy trees and then back to ground cover vegetation as the primary vegetation during the Aalenian–Bajocian. The SEG model analysis demonstrates that the CCP subassemblage is characterized by a low lowland SEG/upland SEG ratio, low wetter/drier ratio within the lowland SEG, and a low warmer/cooler ratio within the lowland SEG. These characteristics reflect the vegetation's response to the ABCE in the Santanghu Basin. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi National Journal of Earth Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: We investigated the mining mode of insect feeding, involving larval consumption of a plant's internal tissues, from the Middle Jurassic (165 million years ago) Daohugou locality of Northeastern China. Documentation of mining from the Jurassic Period is virtually unknown, and results from this time interval would address mining evolution during the temporal gap of mine–seed plant diversifications from the previous Late Triassic to the subsequent Early Cretaceous.Plant fossils were examined with standard microscopic procedures for herbivory and used the standard functional feeding group–damage‐type system of categorizing damage. All fossil mines were photographed and databased.We examined 2014 plant specimens, of which 27 occurrences on 14 specimens resulted in eight, new, mine damage types (DTs) present on six genera of bennettitalean, ginkgoalean, and pinalean gymnosperms.Three conclusions emerge from this study. First, these mid‐Mesozoic mines are morphologically conservative and track plant host anatomical structure rather than plant phylogeny. Second, likely insect fabricators of these mines were three basal lineages of polyphagan beetles, four basal lineages of monotrysian moths, and a basal lineage tenthredinoid sawflies. Third, the nutrition hypothesis, indicating that miners had greater access to nutritious, inner tissues of new plant lineages, best explains mine evolution during the mid‐Mesozoic. See also the Commentary on this article by McLoughlin & Santos, 242: 2391–2393. [ABSTRACT FROM AUTHOR]

The Early‐Middle Jurassic is one of the crucial coal‐forming geologic periods in the world and an important target for hydrocarbon exploration in the Turpan‐Hami Basin, China. The paleoenvironment and vegetation reconstruction of the Early‐Middle Jurassic have been investigated using elemental geochemistry and palynological analysis to reveal paleoclimate evolution. A total of 48 genera of pteridophyte spore and 35 genera of gymnosperm pollen were identified, and 5 palynological assemblages were longitudinally divided, which showed significant differences in geochemical behaviours. The paleoenvironment was a transition from suboxidation to anoxia and then to an oxidation environment under freshwater conditions. The paleowater in the northern Taibei Sag was deeper than that in the southern part during the Middle Jurassic, which coincided with the sedimentary background of the sublacustrine fan in the north and the shallow braided river delta in the south. The paleovegetation evolved from mixed lowland–upland forest in the Hettangian‐Toarcian, to lowland fern forest in the Aalenian‐Bajocian, to upland conifers forest in the early Bathonian, to upland Cheirolepidiaceae forest in the late Bathonian‐Callovian. The Toarcian and Bathonian‐Callovian arid climate and the Hettangian‐Pliensbachian and Aalenian‐Bajocian warm‐humid climate were responses to the continued global warming events and the intensification of the East Asian monsoon circulation, respectively. The influence of the Bathonian‐Callovian aridification event on the sedimentary response in the southern Taibei Sag will be delayed due to the gradual southward migration of the depositional centre. [ABSTRACT FROM AUTHOR]

Our understanding of pre-Cretaceous dinosaur reproduction is hindered by a scarcity of evidence within fossil records. Here we report three adult skeletons and five clutches of embryo-containing eggs of a new sauropodomorph from the Lower Jurassic of southwestern China, displaying several significant reproductive features that are either unknown or unlike other early-diverging sauropodomorphs, such as relatively large eggs with a relatively thick calcareous shell formed by prominent mammillary cones, synchronous hatching and a transitional prehatching posture between the crocodilians and living birds. Most significantly, these Early Jurassic fossils provide strong evidence for the earliest known leathery eggs. Our comprehensive quantitative analyses demonstrate that the first dinosaur eggs were probably leathery, elliptical and relatively small, but with relatively long eggshell units, and that along the line to living birds, the most significant change in reptilian egg morphology occurred early in theropod evolution rather than near the origin of Aves. [ABSTRACT FROM AUTHOR]

Geoheritage is an important resource for contemporary society, and the inventory of geosites remains an urgent task, especially in geologically rich, but poorly known regions. The present study offers a systematic description of the Partisan Glade geosite, which is a large, elongated locality in the western Greater Caucasus. There, tourist activities have accelerated significantly in the past decade. This geosite represents Lower-Middle Jurassic deep-marine siliciclastics, and it shows Upper Jurassic carbonates, unusual landforms, landslides, and tectonic structures. The geosite is heterogeneous, and it consists of five parts with different properties. The Partisan Glade geosite is important for geological research and education. It can also be employed in geotourism development. The multiple scenic views and fascinating landscape contribute to the importance of this geosite as a rising tourist attraction. Some practical implications concerning conservation and planning issues are specified. [ABSTRACT FROM AUTHOR]

Eight fossil tetrapod footprints from lake-shore deposits in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site (SGDS) in southwestern Utah cannot be assigned to the prevalent dinosaurian (Anomoepus, Eubrontes, Gigandipus, Grallator, Kayentapus) or crocodyliform (Batrachopus) ichnotaxa at the site. The tridactyl and tetradactyl footprints are incomplete, consisting of digit- and digit-tip-only imprints. Seven of the eight are likely pes prints; the remaining specimen is a possible manus print. The pes prints have digit imprint morphologies and similar anterior projections and divarication angles to those of Brasilichnium, an ichnotaxon found primarily in eolian paleoenvironments attributed to eucynodont synapsids. Although their incompleteness prevents clear referral to Brasilichnium, the SGDS tracks nevertheless suggest a eucynodont track maker and thus represent a rare, Early Mesozoic occurrence of such tracks outside of an eolian paleoenvironment. [ABSTRACT FROM AUTHOR]

[Objective] The Jurassic was a period of typical fluctuating greenhouse climate that resulted in the deposition of sediments in terrestrial basins. In China, a number of large terrestrial basins were formed during the Jurassic, and the discrepancies in sedimentation records have been preserved in several basins. This study focused on the Middle-Upper Jurassic terrestrial redbeds in the northeastern Sichuan Basin to determine changes in the sedimentary environment and paleoclimate. [Methods] Based on the observation of outcrops, analyses of microscopic clastic composition and C-O isotopes, and to estimate the atmospheric CO2 concentration in this area. [Results] Medium-to-fine clastic rocks are the predominant lithologies, and five sandstones are further classified by composition and lithological content. Three sedimentary environmental units are recognized: meandering river, lake, and paleosol, which represents a simpler system than in the western Sichuan Basin. The upwards facies sequence is pedogenic, beginning with low sand/mud ratio meandering mudrocks in the Middle Jurassic Shaximiao Formation, lacustrine mudrocks with siltstones in the lower Suining Formation of the lower Upper Jurassic, and upward-coarsening and thickening high sand/mud ratio meandering sandstones in the upper Suining and Penglaizhen Formations of the Middle-Upper Jurassic. Two and a half cycles of semi-arid and arid climate were distinguished in the Middle-Upper Jurassic sequence by F/Q and F/L indices, corresponding to the lower Shaximiao Formation, the upper Shaximiao Formation + lower Suining Formation, and the upper Suining Formation + Penglaizhen Formation, respectively. From the pCO2, it is postulated that the Middle Jurassic was relatively cool, becoming warmer in the early Late Jurassic and hot in the middle-to-late Late Jurassic, roughly consistent with the framework of global marine climates. [Conclusion] The climate was (semi-) arid overall in northeastern Sichuan, similar to that in other regions of the Sichuan Basin. It will be necessary to further verify that an intermittent semi-wet climate occurred in western Sichuan and that a hot climate prevailed in northeastern Sichuan. [ABSTRACT FROM AUTHOR]

Copyright of Spanish Journal of Palaeontology is the property of Socieadad Espanola de Paleontologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Mary Anning Rocks charity started as a campaign to raise a statue for the noted early paleontologist and fossil collector Mary Anning in her hometown, Lyme Regis. Now, after the statue was raised, the campaign is still a vibrant and engaging example of how to connect with communities, especially with school-age children. This inclusive and creative campaign ignited far-reaching engagement across a multitude of demographics, but in particular, young women who saw themselves represented in the field of geosciences for the first time. By leveraging Anning's legacy this way, Mary Anning Rocks has helped numerous museums and educators by drawing footfall and helping them open their doors to new audiences. Through the creative use of art, social media, and community engagement, they have harnessed Anning's story to encourage interest and learning in the geosciences, forging connections between scientific discovery, cultural heritage, and local communities.

The Linha São Luiz Geosite is one of the most remarkable outcrops from the central region of Rio Grande do Sul state, southern Brazil. With more than 20 meters of vertical exposure, the locality preserves records of distinct sedimentary episodes, and one of the richest fossil assemblages known in southern Brazil. After a quarter of a century from the first expeditions to the site, the Linha São Luiz still yields new discoveries, registering exquisitely preserved fossils from micro and macrovertebrates, invertebrates, and plants, as well as trace fossils generated by these groups. In this contribution, we assembled representatives from distinct fields of paleontological study to provide a summary of the fossil assemblage from this site. We also briefly discuss the history of research and report geoconservation strategies, which are being implemented at the locality, in order to preserve this important window to the Brazilian Mesozoic.

Abstract A causal mechanism for the Volgian Isotopic Carbon Excursion (VOICE) remains enigmatic. Elemental geochemical profiles of the Deer Bay Formation, Sverdrup Basin, Arctic Canada that record the VOICE and contemporaneous strata are herein examined to provide insight into depositional environments during Late Jurassic‐Early Cretaceous time. Silver (Ag) and Cadmium (Cd) are enriched across the VOICE at localities on Axel Heiberg Island, and in Tithonian (∼Volgian) strata of Ellef Ringnes Island. Other redox‐sensitive trace elements do not exhibit spatially or temporally consistent patterns and indicate oxic conditions. A lack of relationship across the VOICE between Ag and the quality, quantity, and isotopic composition of organic matter suggests that the negative isotope excursion and interval of Ag enrichment are not merely functions of changes in organic matter source or amount, while a lack of spatially consistent change in geochemical indices of weathering similarly excludes climate change and/or sediment provenance as a driver. Therefore, in a ventilated setting and without marked changes in organic matter content, Ag enrichment may be due to hydrothermal activity. Contemporaneous Ag enrichment in strata from Svalbard suggests that a source of hot fluid sufficient to produce Ag‐rich seawater may have been related to rifting in the adjacent proto‐Amerasia Basin. Hydrothermal activity may also have been a widespread source of isotopically depleted carbon. This work develops new geochemical fingerprints that may be used to trace the spatial extent of hydrothermal events that do not leave an extinction pattern but may nonetheless have a far‐reaching influence on biogeochemical systems.

Background The superorder Forcipulatacea is a major clade of sea stars with approximately 400 extant species across three orders (Forcipulatida, Brisingida, Zorocallida). Over the past century, the systematics of Forcipulatacea have undergone multiple revisions by various authors, with some considering numerous families such as Asteriidae, Zoroasteridae, Pedicellasteridae, Stichasteridae, Heliasteridae, Labidiasteridae, and Neomorphasteridae, while others recognized only two families (i.e., Asteriidae and Zoroasteridae). Recent molecular analyses have shown the artificial nature of some of these groupings. Notably, four well-supported clades (Zorocallida, Brisingida, Stichasteridae, and Asteriidae) emerged from a synthesis of morphological and molecular evidence. The majority of extinct forcipulatacean species have been placed in modern families. However, many of these fossil species are in need of revision, especially those species placed within the Asteriidae, the largest of all forcipulatacean families. Methods In light of recent advancements in forcipulatacean systematics, we comprehensively reassess six well-preserved Jurassic forcipulatacean taxa, including the earliest crown-group members from the Hettangian (∼201.4 Ma), and also describe two new Jurassic genera, Forbesasterias gen. nov. and Marbleaster gen. nov. We assembled the largest and most comprehensive phylogenetic matrix for this group, sampling 42 fossil and extant forcipulatacean species for 120 morphological characters. To infer phylogenetic relationships and construct an evolutionary timeline for the diversification of major clades, we conducted a Bayesian tip-dating analysis incorporating the fossilized birth-death process. A total of 13 fossil species were sampled in our analysis, including six taxonomically revaluated herein, two recently reappraised species from the Jurassic, and five additional species from the Cretaceous and Miocene. Results Contrary to prior assumptions, our results indicate that none of the Jurassic taxa investigated belong to Asteriidae or any other modern families, and instead represent stem-forcipulatids. Furthermore, our phylogenetic results suggest that Asteriidae likely originated during the late Cretaceous. Our findings highlight a greater early diversity within the Forcipulatacea than previously presumed, challenging existing perceptions of the evolutionary history of this significant clade of marine invertebrates.

Geoheritage is an important resource for contemporary society, and the inventory of geosites remains an urgent task, especially in geologically rich, but poorly known regions. The present study offers a systematic description of the Partisan Glade geosite, which is a large, elongated locality in the western Greater Caucasus. There, tourist activities have accelerated significantly in the past decade. This geosite represents Lower–Middle Jurassic deep-marine siliciclastics, and it shows Upper Jurassic carbonates, unusual landforms, landslides, and tectonic structures. The geosite is heterogeneous, and it consists of five parts with different properties. The Partisan Glade geosite is important for geological research and education. It can also be employed in geotourism development. The multiple scenic views and fascinating landscape contribute to the importance of this geosite as a rising tourist attraction. Some practical implications concerning conservation and planning issues are specified.

A modern seismic interpretation of coastalcontinental deposits in the Jurassic complex of one of the fields in the north of the West Siberian Oil and Gas Province, including simultaneous stochastic inversion of seismic data was performed. The main object of the study was the interval of the group of J2 reservoirs. Petro-elastic modeling was carried out on the project. Modelling includes six wells with geophysical well logs. Feasibility study shows possibility of predicting lithology by stochastic inversion. In addition, optimal parametrization of elastic properties was determined to separate water-saturated and gas-saturated reservoirs from clay deposits. Interpretation of well and seismic data, as well as the results of stochastic inversion, made it possible to identify play zones in target interval. Probability cubes of gas-saturated reservoirs, made it possible to map the lenticular structure of the reservoirs and substantiate hydrodynamic barriers between individual gas plays.

The shale oil and gas exploration potential of the Jurassic Qianfoya Formation in the Sichuan Basin is promising. However, there is still a lack of understanding regarding the basic sedimentary characteristics and development patterns of fine-grained sedimentary rocks. Therefore, utilizing the principles of fine-grained sedimentology, this study thoroughly examines the geological features of the fine-grained sedimentary rock reservoir in the second member of the Qianfoya Formation in the Yuanba area. This investigation includes the analysis of material composition, sedimentary structures, reservoir space types, and classification of lithofacies types. Subsequently, the physical characteristics and reservoir space types of the main lithofacies reservoirs are compared and analyzed. Finally, the study predicts the favorable intervals for development. The results reveal that the fine-grained sedimentary rocks in the second member of the Qianfoya Formation in the Yuanba area consist of two rock types: clay rock and siltstone, with a total of 15 rock facies types. Organic-rich massive clay rock, organic-rich massive silty clay rock, organic-rich laminated silty clay rock, organic-rich banded silty clay rock, organic-rich massive silty clay rock, and organic-rich laminated silty clay rock are the six major lithofacies types of fine-grained sedimentary rock. Additionally, various types of reservoir spaces exist, such as interlayer fractures among clay minerals, shale bedding fractures, intercrystalline pores among clay minerals, intercrys-talline pores among iron pyrite, dissolved pores, and organic matter pores. Among these, intercrystalline pores of clay minerals are the most widely distributed. The average porosity and permeability of the six major lithofacies types were found to be 2% and 0.023×10-3 μm2, respectively. The lithofacies of organic-rich laminated silty clay rock, organic-rich laminated silty clay rock, and organic-rich massive silty clay rock exhibit rich reservoir space types, wide distribution, large quantity, higher porosity and permeability compared to other lithofacies, as well as higher TOC values, making them the most favorable reservoir lithofacies types. The dominant stratum of the second member of the Qianfoya Formation in the study area is situated in substratum 1, the bottom of substratum 2, and the middle and lower parts of substratum 3.

The Fuxing area of the Sichuan Basin is known for its multiple sets of organic-rich shale in the Jurassic period, with several wells yielding significant amounts of industrial oil and gas. Understanding the characteristics and factors influencing the enrichment of different shale facies sedimentary reservoirs is crucial for effective exploration. Through detailed rock core descriptions, experimental analysis, and drilling exploration, the author has classified and compared fine-grained sedimentary rock facies in terrestrial strata, characterized reservoirs, identified types of oil and gas reservoirs, and analyzed the main factors influencing enrichment and productivity. The study reveals that the Jurassic strata in the Fuxing area contain two sets of high-quality shale with semi-deep lacustrine facies: the first sub-section of the Dongyuemiao section of the Ziliujing Formation and the lower sub-section of the second section of the Lianggaoshan Formation. These shale layers exhibit multi-layer stacking, moderate TOC content, well-developed bedding, integrated source storage, and high gas/oil ratio characteristics. The lithology of these target shale layers is complex, leading to the establishment of a four-element lithofacies classification scheme based on "color-TOC-sedimentary structure-mineral composition". This scheme identifies the gray-black high carbon sand-laminated clay shale as the favorable lithofacies for the lower sub-section of the second section of the Lianggaoshan Formation, and the gray-black high carbon medium debris-laminated and fine sand medium debris-laminated clay shale as the favorable lithofacies for the eastern sub-section. The three lithofacies in the study area are horizontally distributed in a stable manner. The gray-black high carbon fine sand layer, medium debris layer, and fine sand-medium debris layer type clay shale exhibit reservoir characteristics of "porous coexistence, large pores and throats, and integrated pores and fractures". These reservoir properties, including good permeability, facilitate the efficient storage and flow of shale oil and gas in the pore-fracture storage system. The first sub-section of the Dongyuemiao section is a condensate gas reservoir, while the lower sub-section of the Lianggaoshan Formation's second section is a volatile oil reservoir. Key factors contributing to the enrichment of continental shale oil and gas have been identified, including medium to high hydrocarbon generation potential and strong retention rates supporting the accumulation of laminated shale oil and gas. A favorable hydrocarbon-diagenesis-reservoir formation configuration promotes oil and gas accumulation. Additionally, the development of micro cracks and suitable thermal evolution aids in hydrocarbon enrichment and flow, while large, wide, gentle synclines and high-pressure overpressure conditions support the sustained preservation of hydrocarbons.