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Storm deposits in marine facies are distributed widely across all geological periods, greatly extending the historical record of storms and providing valuable insights into the ongoing debate regarding the link between tropical cyclone activity and global climate change. This paper reviews the processes for identifying, interpreting, and analyzing the evidence of paleostorms across various depositional environments. We developed a range of regional storm deposit models and contributed to paleostorm reconstruction efforts, including studies on distinguishing storm deposits from tsunami deposits. Research has indicated that the sedimentary characteristics of storm deposits, such as lithology, sedimentary structures, and palaeontological markers, are effective in identifying storm events. This paper presents examples of storm deposits from the Late Cambrian in the Alborz region of Iran, the Early Paleocene in southwestern Iran, and the Middle Holocene in Durban, South Africa and examines the influence of storm activity on the formation of banded rock features and the impact of storm deposits on hydrocarbon reservoirs. Furthermore, this study explores advanced methods for studying storm deposits, including microfossil tracing, geochemical analyses, laboratory analog experiments, ground-penetrating radar (GPR), and the identification of mineral luminescence properties. The findings suggest that storm deposits not only shed light on the relationship between storm activity and global climate change but also offer new ideas for hydrocarbon exploration and development. Studying storm deposits in marine environments is critical for mitigating the damage and economic losses from extreme tropical cyclones and advancing the field of storm sediment research within geology. [ABSTRACT FROM AUTHOR]

Oncoids, significant sedimentary structures within the Jurassic strata of the Mediterranean Region, serve as valuable indicators of paleoenvironmental conditions during their formation. One of the important examples of oncoids has been discovered in the Pliensbachian (Early Jurassic) Ammonitico Rosso Facies (ARF) of the eastern Sakarya Zone (Eastern Pontides, NE Turkey). This study presents the first comprehensive sedimentological and petrographic (textural and compositional characteristics) examination, as well as geochemical analyses (trace and rare earth elements) of these Fe-Mn oncoids. The oncoids consist of nuclei coated with irregular laminae and exhibit a range of sizes, from 10 to over 45 mm, displaying various colours such as brown, reddish, and metallic-looking. They mostly have a discoidal shape, although some are spherical. The nuclei consist of bioclastic wackestones, containing remnants of ammonoid shells. Some oncoids, especially the discoidal forms, have multiple nuclei. The cortex of the oncoid predominantly consists of wrinkled bands displaying micritic laminae, with an abundance of filamentous bodies and the local presence of encrusting microfossils. In the cortex of the oncoids, iron predominates over manganese, and there are compositional variations within the cortex, especially enriched in Si, Fe, and Ca. They predominantly fall within the region associated with hydrothermal Fe and Mn sediments, as indicated by discrimination diagrams involving Ni, Co, Zn, and plots of Ce/Ce* vs Y/HoN and Nd contents, suggesting a hydrothermal origin. Furthermore, their rare earth elements (REE) chemistry displays distinct Y/Ho, Sm/Yb, Ce/Ce, and Nd values, indicating the presence of seawater mixing with hydrothermal fluids. However, they show relatively low Sm/Yb, Y/Ho, Eu/Sm, Nd/YbN, and La/Yb values, suggesting a limited contribution from hydrothermal sources to the surrounding seawater. Nevertheless, the cortex of the oncoids exhibits a complex and variable mineralogy that changes over short distances, implying the dynamic nature of the depositional environment, characterized by fluctuating hydrological regimes, varying oxygen levels, elemental supply, and the saturation of specific elements in seawater. The increased presence of specific trace elements, including Fe, and REE during this period, is likely linked to hydrothermal fluid input into marine environments, coinciding with intensified syn-sedimentary tectonic activity, where ongoing extensional tectonic movements occasionally influenced paleoenvironmental conditions. In these conditions, the formation of oncoids is influenced by various sedimentary factors, including the availability of metal sources, specific paleoenvironmental conditions, and the presence of microbial organisms, thereby enriching our understanding of palaeogeography during the Early Jurassic period. Additionally, the studied oncoids, with their comparable stratigraphic position and petrographic characteristics to those in both the eastern and western parts of the Tethyan basin, underscore their significance in palaeogeography and stratigraphy. [ABSTRACT FROM AUTHOR]

The CLose-UP Imager (CLUPI) onboard the ESA ExoMars rover is a camera system that will be used for capturing high-resolution images of Martian rocks and soil. The goal of this study was to define a method based on the Structure-from-Motion (SfM) that allows for generating stereoscopic and three-dimensional data from CLUPI images. Although CLUPI is a mono-optic camera, we were able to identify the ideal CLUPI positioning and calculate the rover movements necessary for acquiring images in a given rover position that we subsequently processed to produce stereoscopic photographs and derive 3D and topographical data with Agisoft. To perform this feasibility test in our laboratory, using the EM+, a CLUPI representative engineering model, the 3D and topographical reconstruction was based on a translation of the rover, on the "close-up outcrop observation" configuration in a fixed drill position. The two acquired images, one before and one after the rover's translation are the stereo pairs needed to perform the digital outcrop model (DOM) reconstruction. By importing the data into Geographic Information System (GIS) software, we generated maps, profiles, and stream maps, which enable a detailed characterization of rock textures and sedimentary structures (e.g., clast and phenocryst shape, size, and distribution, laminations thickness and angular relationships...). This study proposes a method easily reusable for creating 3D and stereo data with CLUPI images. [ABSTRACT FROM AUTHOR]

Since diagnostic primary depositional sedimentary structures and depth‐dependent grain‐size trends are rarely preserved, building a comprehensive sequence stratigraphic framework for the vast majority of the Phanerozoic carbonate platform sequences is pending. Among the two most important sequence stratigraphic surfaces, while the subaerial unconformity can be reliably identified by either karst development or the appearance of siliciclastic materials, the demarcation of the maximum flooding surface remains difficult in lithologically uniform shallow marine carbonate sequences. The present study attempts to identify the globally documented maximum flooding surface within the body of the negative carbon isotope excursion of the Palaeocene–Eocene Thermal Maximum recorded in the shallow marine carbonate platform sequences. The results show that, along with the carbonate microfacies, the yttrium to holmium ratio (Y/Ho ratio) of the carbonate fraction reliably records the sea‐level changes. A Y/Ho ratio between 70 and 80 demarcates the stratigraphic position of the maximum sea‐level state (the most open marine condition in the studied interval) and maximum flooding surface in the studied sections. Since the Y/Ho ratios remain relatively stable throughout diagenesis, they can be used for maximum flooding surface identification in shallow marine carbonate platform sequences. The possibility exists that the same method can also be applied to the mixed siliciclastic–carbonate systems. [ABSTRACT FROM AUTHOR]

Purpose: The non-uniform sedimentary structure of tailings storage facilities (TSFs) has significant adverse effects on dam seepage and stability. However, the spatial distribution of tailings is disordered and the resulting sedimentary structures of TSFs have not been thoroughly understood. The objective is to investigate the complex sedimentary structures of tailings under different discharge conditions. Methods: A flume with a length of 20 m and a width of 2 m was built, and a series of flume tests with different discharge parameters were conducted. The depositional characteristics and formation mechanism were statistically investigated in terms of particle size distribution in the horizontal and vertical directions, the micro fabric of sediment, and the interlayer structure. Results: The hydraulic sorting is obvious. In the transitional region between the channel zone and laminar flow zone, d50 and d10 both undergo a sudden decrease. Vertically, the mean particle size of sediment is linearly related to the depth of each profile. The fabric pattern of sedimentary particle orientation changes from a spindle shape to a circular shape with increasing slurry concentration or decreasing discharge flow rate, indicating that particle deposition is clearly anisotropic and directional. Three new types of interlayers were observed: silt or clay interlayers in sand layers, sandy lenticles interbedded in muddy sediment and bedding structure interlayers. Conclusions: This study represents the first effort to analyse the micro fabric characteristics of tailings sediment and the formation mechanism of interlayer structure. This quantitative study provides useful information for the modelling and safety evaluation of TSFs. [ABSTRACT FROM AUTHOR]

The geophysical inversion problem is inherently underdetermined. Constrained inversion, by incorporating prior information, can effectively reduce the ambiguity in inversion results. A key research challenge lies in establishing a reasonable coupling mechanism between the prior information and the inversion model. Traditional cross-gradient coupling methods often exhibit weak coupling effects in regions with small model gradients. In this paper, we introduce a new coupling method called "minimum cross-gradient support" (MCGS), which enhances the balance between model gradient magnitude and the influence of gradient direction by applying a minimum support function to the cross-gradient. We evaluated the coupling effects of MCGS in comparison with two others coupling methods: normalized cross-gradient (NCG) and joint minimum gradient support (JMGS), the latter of which also employs the minimum support function. Theoretical models demonstrate that MCGS retains the advantage of reduced dependence on strictly accurate prior information, enhances constraint effectiveness in weak gradient regions, and the strength of constraints can be flexibly adjusted through focusing factors. To verify the effectiveness of MCGS, we conducted two synthetic experiments: a double-blocks model and a nappe structure model, applied to magnetotelluric (MT) constrained inversion. The results showed that MCGS constrained inversion achieved better performance than both non-constrained inversion and cross-gradient constrained inversion, with lower residual cross-gradient values and higher model recovery accuracy compared to the true model. Finally, we applied the proposed MCGS coupling to real data sets from the Junggar Basin. The inversion results revealed the resistivity structure of the sedimentary layer and imaged possible residual Carboniferous sediments beneath the Permian, as well as the distribution of the Paleozoic basement. These results provide valuable evidence supporting the subduction tectonic evolution model of the region. [ABSTRACT FROM AUTHOR]

Subsurface erosion is a poorly recognized but important process for modelling and predicting gully erosion rates in loess areas. It is crucial to recognize the factors and mechanisms of soil piping and pipe collapse development. Our research is the first detailed description of the complex evolution of large collapsed pipes on the banks of a loess gully over 25 years (west part of Nałęczów Plateau, Lublin Upland). The objective of this study was to reconstruct the development of piping forms as a result of land use change. Detailed field observations and measurements after snowmelt and rainfall-runoff events formed the basis of the research. Sedimentary structures observed in the walls of recently collapsed pipes, filling up older piping forms, were studied. The human impact on the development of collapsed pipes has been significant. We found a multi-stage development of these forms with several cut and fill phases. An important factor influencing the formation and development of these forms was the change in land use (crop type and tillage direction). Farmers tried to reclaim collapsed pipes by filling them in with soil and incorporating them into the cropland. The resulting depressions had high infiltration rates resulting in a reactivation of soil piping processes. Increase of precipitation and the intensity of runoff caused the secondary stage of collapsed pipes development (with a volume ranging between 240 and 912 m3 per collapsed pipe). Changing runoff patterns as a result of human interventions decreased their activity, but caused the development of new (secondary) collapsed pipes. [ABSTRACT FROM AUTHOR]

The study of thin sections provides crucial information about the structure of sedimentary rocks. Different properties, such as mineral composition, texture, grain morphology, presence of clay minerals, and porosity level, can be derived from thin section analysis. These features directly determine the quality of crude reservoirs. In this context, manual grain identification from petrographic thin sections usually demands considerable time and effort, so machine learning and image processing techniques have become more frequent in the last few years. Obtaining large and reliable labeled data sets for supervised learning workflows is a complex and critical process. We devise a completely unsupervised approach for granulometric classification using thin section images. The introduced workflow first pre-processes the thin section image by denoising and dividing it into different image patches. In the second stage, the image patches are used to train an unsupervised convolutional neural network. Then, the trained network segments the grains in each patch of the pre-processed image. The training strategy uses transfer learning to guarantee the same initialization parameters of the neural network while processing the image patches. Next, a watershed transform is applied to recover the borders of the segmented grains. Finally, a granulometric calculation and classification process is performed by considering the grain contours restored through the implemented methodology. The results obtained with the proposed algorithm are concordant with those obtained from the analysis of sieved thin sections derived from controlled experiments in the laboratory. [ABSTRACT FROM AUTHOR]

Peatlands are highly sensitive ecosystems that respond to hydrological, climatic, and geomorphological changes. In this study, we investigate the origin and historical evolution of a peatland located in Northeastern Romania, on the Suceava plateau. Our approach includes the analysis of historical maps and physical characteristics of both the peat (grain size, LOI - loss on ignition) and water (pH, dissolved oxygen, electrical conductivity). Our findings suggest that the development of this peatland has been more prominent along the surface than the depth. The presence of gravel and sand at the base of the peat deposit, along with surface morphological evidence, supports the hypothesis that this peatland originated in an ancient paleomeander. pH analysis indicates that the peatland is mesotrophic, while granulometric and LOI analyses suggest a fluviogenic origin.The significant changes observed in the sedimentary structure of the peatland may be attributed to climate change, with potential anthropogenic influences over the past 50 years. Furthermore, our study contributes valuable insights to geomorphological research in the Suceava valley, revealing visible changes spanning the last 250 years. [ABSTRACT FROM AUTHOR]

Supercritical flows and their associated upper‐flow‐regime bedforms have been increasingly recognized in several contrasting depositional environments around the world, including volcano‐sedimentary settings. In recent years, there have been significant advances in flow modelling, architecture and depositional dynamics in upper‐flow‐regime bedforms related to glacio‐volcanic interaction, however most of these works come from specific volcanic landscapes. Examples of other regions with different tectonic and volcanic settings are needed in order to gain a more global perspective regarding the generation and preservation of upper‐flow‐regime glacio‐volcanic bedforms. This study presents a detailed analysis of Pleistocene volcaniclastic deposits accumulated in alluvial to lacustrine deltaic environments in the Southern Andes within the Southern Volcanic Zone. Six facies were defined and related to distinctive bedforms by examining sedimentary features, including textural characteristics, sedimentary structures, architecture and composition. Among these facies, five are distinguished by deposition from supercritical flows and upper‐flow‐regime bedforms, such as cyclic steps, chutes and pools, and antidunes. The stratigraphic succession reveals a predominance of repeated supercritical flows, which appear to be influenced by the availability of detritus for removal along with sudden water discharges. Compositional analyses indicate that explosive volcanism was the primary source of detritus, occurring synchronously with sedimentation. Additionally, the widespread occurrence of Pleistocene glacial conditions in this region suggests that volcanic‐induced melting ice or snow may have been an important source of water supply. Regarding the Southern Andes, the presence of local depressions, such as volcano‐tectonic calderas plays an essential role in the generation and preservation of the upper‐flow‐regime bedforms related to glacio‐volcanism. Furthermore, the importance of carrying out detailed and multidisciplinary studies seems to be critical for the recognition of these deposits in the record of the Andes. [ABSTRACT FROM AUTHOR]

Imaging the detailed structure of sedimentary basins is crucial for natural resource exploration and essential for better analysis and correction of sediment responses when studying deeper interior earth structures using seismic data. In the Tarim Basin, previous studies on the sedimentary structures are mostly obtained by active-source seismic surveys, which can provide high-resolution underground interface information but are highly costly or environmentally unfriendly. In this paper, ambient noise tomography, an efficient and economical method based on background vibration, is employed to construct the sedimentary velocity structure at the southeast margin of the Tarim Basin. Based on ambient noise data collected from a linear dense short-period seismic array, we extract Love wave signals from T–T component cross-correlation functions (CCFs) and measure Love wave dispersion curves at a period band of ∼0.3–11.5 s. Then, we utilize a one-step direct surface wave tomography method to image a fine 2-D sedimentary shear wave velocity structure with a depth reaching 10 km. Our results reveal a clear layered sedimentary structure, the palaeo Tadong uplift and the thrust Cherchen fault. Our study provides reference sedimentary velocity models for the southeastern Tarim Basin, focusing on depths shallower than 10 km. This model is intended to serve as crucial input for studies requiring detailed shallow sedimentary velocity data. Moreover, our research demonstrates that the application of the ambient noise tomography method with dense arrays has great potential for enhancing resource exploration efforts in sedimentary basins. [ABSTRACT FROM AUTHOR]

The Arctic, an essential ecosystem on Earth, is subject to pronounced anthropogenic pressures, most notable being the climate change and risks of crude oil pollution. As crucial elements of Arctic environments, benthic microbiomes are involved in climate-relevant biogeochemical cycles and hold the potential to remediate upcoming contamination. Yet, the Arctic benthic microbiomes are among the least explored biomes on the planet. Here we combined geochemical analyses, incubation experiments, and microbial community profiling to detail the biogeography and biodegradation potential of Arctic sedimentary microbiomes in the northern Barents Sea. The results revealed a predominance of bacterial and archaea phyla typically found in the deep marine biosphere, such as Chloroflexi, Atribacteria , and Bathyarcheaota. The topmost benthic communities were spatially structured by sedimentary organic carbon, lacking a clear distinction among geographic regions. With increasing sediment depth, the community structure exhibited stratigraphic variability that could be correlated to redox geochemistry of sediments. The benthic microbiomes harbored multiple taxa capable of oxidizing hydrocarbons using aerobic and anaerobic pathways. Incubation of surface sediments with crude oil led to proliferation of several genera from the so-called rare biosphere. These include Alkalimarinus and Halioglobus , previously unrecognized as hydrocarbon-degrading genera, both harboring the full genetic potential for aerobic alkane oxidation. These findings increase our understanding of the taxonomic inventory and functional potential of unstudied benthic microbiomes in the Arctic. [ABSTRACT FROM AUTHOR]

[Objective] Sedimentary differences are the key factor in controlling reservoir heterogeneity. Analyzing reservoir heterogeneity through sedimentary microfacies is crucial for oil and gas field development and sweet spot prediction, and it also informs the evaluation of fracturing in tight sandstone reservoirs. There are many types and complex lithologies of unconventional oil and gas reservoirs in the Ordos Basin as well as many factors controlling reservoir fracability. At present, mechanical experiments are used to comprehensively characterize the fracturing property; however the research cost is high and the experimental process is complicated, making it unnsuitable for large-scale oilfield development and use. Therefore, this study attempted to analyze and compare the fracability of tight sandstones with different sedimentary microfacies from the perspective of sedimentary microfacies controlling the lithology and reservoir development to provide a reference for oilfield development plans. [Methods] Taking the compact sandstone of Chang 7 member of Yanchang Formation in the Longdong area of Ordos Basin as the research object, the different types of microfacies are identified through the data of core and cast slice, the mineral composition and structural parameters of rock samples were obtained by X-ray diffraction (XRD) analysis, and rock mechanics experiments were conducted to quantitatively described the fracturing property. [Results] The results are as follows: (1) Two sedimentary microfacies, namely underwater distributary channel and sheet sand, mainly developed in Chang 7 Member of Yanchang Formation in the study area. Among them, the single sand body thickness of the underwater distributary channel is greater than 2 m, the sheet sand is mostly a medium thin and thick sand mudstone interlayer, and the single sand body thickness is generally less than 2 m. (2) The composition and structure of the two sedimentary sandstone microfacies are obviously different: the content of carbonate minerals, clay minerals, and heterobases in the sheet sand microfacies are relatively high, the particle size is finer, and the sorting is worse, which are the main internal factors that cause the difference in tight sandstone fracability and are the basis for judging the fracability of tight sandstone by sedimentary microfacies. (3) The fracability index was related to the composition and structure of sandstone. In terms of composition, the fracability index was positively correlated with quartz mineral content as well as carbonate mineral content and negatively correlated with feldspar mineral content. In terms of structure, there is a negative correlation between the fracability index and the average particle diameter 9. The larger the particle size, the higher the fracability index. The fracability index was positively correlated with the standard deviation of the particle size, indicating that the worse the particle separation, the higher the fracability index. (4) Through grey correlation analysis, it was found that the degree of influence of sandstone parameters on fracability was in the order of carbonate mineral content, quartz content, standard deviation of particle size, and average particle size from high to low, while clay minerals and feldspar content were in a relatively weak position. [Conclusion] The results indicate that the higher the contents of carbonate and quartz and the higher the standard deviation of particle size (the worse the sorting), the better the fracability. The finer the particle size, the higher the feldspar content and the worse the fracability. Grey correlation analysis showed that the carbonate mineral content, separation and particle size play a major role in the fracability of tight sandstone. Compared with distributary channel microfacies, sheet sand has a higher carbonate minerals content, worse sorting, and little difference in quartz content. Although the microphase particle size of the sheet sand is slightly finer, the average particle size has a relatively minor effect on the fracability; thus, sheet sand as a whole shows better fracability. [Significance] Since the standard deviation (sorting) and particle size of sandstone particles are controlled by sedimentary microfacies, and the content of carbonate minerals is directly controlled by sandstone thickness and indirectly affected by sedimentary microfacies, the change in the tight sandstone fracability index can be judged according to the difference in sedimentary microfacies in practical engineering, and the working process can be simplified. [ABSTRACT FROM AUTHOR]

The Minle manganese (Mn) deposit is a typical Mn-bearing deposit in the Datangpo Formation in southern China. The metallogenic environment and associated changing processes directly determine the migration, enrichment, and precipitation of Mn. To have a better understanding of the metallogenic structure, magnetotelluric (MT) method was performed to explore the Minle deposit. Electrical spindle analysis of MT data was conducted based on the Swift decomposition and the phase tensor decomposition, and inversion of the transverse-electric (TE) and transverse-magnetic (TM) models was carried out using the Occam inversion method. The results revealed that the main structural strike of the MT section was approximately 37° north to east and obtained the distribution characteristics of the deep electrical properties in the study area. The "concave structure" in the resistivity model is the main geophysical marker for delineating the Mn-ore body. In the metallogenic structure of Mn ore, a "funnel-shaped structure" of the strata was found, which provided favorable space for the percolation and enrichment of Mn deposits. The results of this study will be helpful in improving geophysical prospecting techniques for sedimentary Mn deposits in southern China. [ABSTRACT FROM AUTHOR]

Biogenic sedimentary structures offer a unique perspective for understanding the role of the biosphere in the interaction with other Earth subsystems and the building up of our planet. The record of their ancient equivalents provides a wealth of information for reconstructing the role of bioturbators as ecosystem engineers using multiple ichnological proxies and methods. In this study, we present an overview of how bioturbation has worked across a broad range of spatial and temporal scales from the perspective of ecosystem engineering. Comprehensive and systematic datasets allow analyses at regional and global spatial extents, and especially over long temporal scales where sampling intensity and rock record biases can be considered. Our results underscore the significance of the Cambrian Explosion in the establishment of modern‐style shallow marine ecosystems and of the Ordovician Radiation for their deep marine counterparts, as well as the continuous ecosystem impact of bioturbation during Palaeozoic terrestrialization. Comparable datasets for the rest of the Phanerozoic have not yet been compiled. However, preliminary information indicates that colonization of ultra‐deep tiers, the rise to prominence of regenerators, increased burrowing efficiency, and increased compartmentalization of the endobenthic ecospace, were products of the Mesozoic Marine Revolution. The trace‐fossil record offers hard data to evaluate bioturbation as a driving force in ecosystem re‐structuring and as a key factor in geobiological cycles. Models assessing these fundamental issues should be rooted empirically at different scales, from both autoecological and synecological to macroecological, making the best possible use of the rich and rapidly developing ichnological toolbox. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous limestones unconformably overlie Upper Carboniferous coal-bearing lithologies and are studied to assess their effect on rising mine-water levels in the Ruhr mining district. Upper Cretaceous sedimentary rocks from the Münsterland Cretaceous Basin have previously been studied regarding their sedimentary structures and fossil content. However, understanding the petrophysical and petrographic heterogeneity in regard to sedimentary properties and their effect on fluid migration pathways is yet missing. Utilizing He-pycnometry, Klinkenberg-corrected air permeabilities, p-wave velocities, transmitted and reflected light analyses, point-counting and cathodoluminescence, we assess the petrophysical, geomechanical and mineralogical properties. Porosity ranges from 1.0 to 18.7% and permeability ranges from < 0.0001 to 0.2 mD, while p-wave velocity ranges between 2089 and 5843 m/s. Mechanical compaction leads to grain rearrangement, deformation of calcispheres, foraminifera and ductile clay mineral laminae. Above and below clay laminae, compaction bands of deformed calcispheres develop. Early diagenetic mineral precipitation of ferroan calcite in inter- and intragranular pores reduces porosity and permeability and influences geomechanical properties. An underestimated aspect of limestone petrography is the relationship of the original primary compactable depositional volume and the influence of compaction, deformation and cementation during early and late diagenesis on reservoir properties. The detrital dominated limestones show an originally high compactable depositional volume (CDV). Overall, reservoir qualities are poor and indicate the sealing potential of the studied lithologies. The Upper Cretaceous (Campanian) limestones thus may act as a barrier for increasing mine-water levels from dismantled, post-mining subsurface hard coal mines in the region. [ABSTRACT FROM AUTHOR]

A detailed morphological study has been conducted for the first time on theropod tracks found in the Lower Cretaceous Tugulu Group in the Turpan-Hami Basin, Xinjiang. Based on the small size, the low length/width ratio, and the low anterior triangle length/width ratio, these theropod tracks are classified into cf. Eubrontes. These findings provide direct evidence for the presence of theropod dinosaurs within the Hami pterosaur fauna. Furthermore, by considering the length of the footprints, it is estimated that the trackmakers had a hip height of approximately 65 cm and a body length of about 171 cm, indicating that these tracks were made by small theropods. Additionally, when taking into account the invertebrate traces, the sedimentary structure, and the lithostratigraphic sequence of the section, these footprints were likely left along the shoreline of a shallow lake. [ABSTRACT FROM AUTHOR]

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The editorial "Recent Advances in Sedimentology" published in the Journal of Marine Science & Engineering discusses the importance of sedimentary rocks in Earth's geological framework and their economic potential in construction and hydrocarbon exploration. The special issue includes ten research articles focusing on sedimentological research in Greece and other sedimentary basins, offering valuable insights into sedimentary processes, depositional environments, and reservoir characteristics. The articles cover a range of topics, from carbonate deposits in Pakistan to the sedimentary distribution of estuaries, providing diverse perspectives and advancing cutting-edge methodologies in sedimentology. [Extracted from the article]

This paper explores the response to Holocene ash inundation in different sub‐environments of two fluvio‐lacustrine systems, Las Piedritas and Totoral, focussing on the processes of volcaniclastic remobilisation. Sediment cores and outcrops were used to recognise three deposit types, noting how some differ from lahars, through sedimentological and stratigraphic analysis: (1) thick, laterally discontinuous, pumice‐dominated deposits occur overlying alluvial plain and lower terrace surfaces across both watersheds; (2) chaotic, extremely poorly sorted and matrix‐supported beds composed of both epiclastic and pyroclastic material occur as two conspicuous deposits at Las Piedritas outcrops, in a low‐gradient confined channel setting; and (3) layers with an exclusively pyroclastic composition and no flow sedimentary structures or fragment roundness were found draping each of the two chaotic intervals and intercalating with the background sediment in Las Piedritas prodelta. Thick pumice packages capping the floodplains resulted from the overflow of streams carrying a floating pumice load. Due to its positive buoyancy, the pumice is transported as a slowly moving overlying mantle without mixing with the streamflow. The disorganised pattern and poor sorting of the matrix‐rich polymictic beds are consistent with laminar, gravity‐driven, high‐concentration flows. They constitute secondary lahars, originating upstream from large run‐off processes that reworked a pyroclastic substrate. The lack of reworking features in the vitric‐rich units identified in the lake core retrieved from Las Piedritas prodelta, as well as the continuous and widespread occurrences of those interbedded in upstream outcrops, indicate an airfall origin. No reworked tephra unit is recognised in the prodelta sediment record, although various deposits from the hydrologic remobilisation of airfall tephra are found along the subaerial portion of both watersheds. Apparently, large amounts of flotation‐remobilised tephra were retained on the delta plain, while another considerable fraction would have been carried away from the creek mouth under the influence of dominant regional winds. [ABSTRACT FROM AUTHOR]

Over the past decade, there has been growing interest in the sedimentological community to use micro X‐ray computed tomography to analyse microfacies in sediment cores. However, little attention has been paid to the application of micro‐computed tomography in lithified deposits, even though this can allow their texture to be characterised in three dimensions, providing key information about sedimentary structures. A novel application of micro‐computed tomography in lithified sediment‐gravity flow deposits is presented with the objective of characterising their internal 3D sedimentary structures. This technique is applied to three deep‐marine sandstones showing different compositional properties: Cretaceous Gosau Group (Austria), Eocene Hecho Group (Spain) and the Oligocene Annot Formation (France). From micro‐computed tomography data the size of particles and their distribution throughout the sample is reconstructed in 3D permitting a better visualisation of sedimentary textures. Particle distributions computed from micro‐computed tomography are similar to those computed from thin section image analysis, corroborating the reliability of the micro‐computed tomography to evaluate grain‐size trends. Micro‐computed tomography is complemented with micro‐X‐ray fluorescence and thin section petrographic analyses. In cases where mineral composition or grain size are homogeneous or matrix and grains have similar mineral composition, sedimentary structures do not appear visible from micro‐X‐ray fluorescence or thin section analyses. By separating particles based on their computed tomography density, it is possible to isolate the coarsest fraction, highlighting the sedimentary structures. This study demonstrates (i) the potential of micro‐computed tomography in analyses of sedimentary structures from outcrop data and (ii) the importance of the mineralogical composition and degree of grain sorting in assessing the origin of structureless deposits. Considering the importance of visualising sedimentary structures when interpreting depositional processes, micro‐computed tomography is a new and reliable tool to assess the physical properties of sandstones and to analyse their internal 3D sedimentary structures. [ABSTRACT FROM AUTHOR]

Abstract Over the past decade, there has been growing interest in the sedimentological community to use micro X‐ray computed tomography to analyse microfacies in sediment cores. However, little attention has been paid to the application of micro‐computed tomography in lithified deposits, even though this can allow their texture to be characterised in three dimensions, providing key information about sedimentary structures. A novel application of micro‐computed tomography in lithified sediment‐gravity flow deposits is presented with the objective of characterising their internal 3D sedimentary structures. This technique is applied to three deep‐marine sandstones showing different compositional properties: Cretaceous Gosau Group (Austria), Eocene Hecho Group (Spain) and the Oligocene Annot Formation (France). From micro‐computed tomography data the size of particles and their distribution throughout the sample is reconstructed in 3D permitting a better visualisation of sedimentary textures. Particle distributions computed from micro‐computed tomography are similar to those computed from thin section image analysis, corroborating the reliability of the micro‐computed tomography to evaluate grain‐size trends. Micro‐computed tomography is complemented with micro‐X‐ray fluorescence and thin section petrographic analyses. In cases where mineral composition or grain size are homogeneous or matrix and grains have similar mineral composition, sedimentary structures do not appear visible from micro‐X‐ray fluorescence or thin section analyses. By separating particles based on their computed tomography density, it is possible to isolate the coarsest fraction, highlighting the sedimentary structures. This study demonstrates (i) the potential of micro‐computed tomography in analyses of sedimentary structures from outcrop data and (ii) the importance of the mineralogical composition and degree of grain sorting in assessing the origin of structureless deposits. Considering the importance of visualising sedimentary structures when interpreting depositional processes, micro‐computed tomography is a new and reliable tool to assess the physical properties of sandstones and to analyse their internal 3D sedimentary structures.

Fluvial cross strata are fundamental sedimentary structures that record past flow and sediment transport conditions. Bedform preservation can be significantly influenced by the presence of larger‐scale topographic features that cause spatial gradients in flow. However, our understanding of the controls on cross strata preservation in the presence of a morphodynamic hierarchy is limited. Here, using high‐resolution bathymetry from a physical experiment, we quantify bedform evolution and cross strata preservation in a zone of flow expansion and deceleration. Results show that the size and celerity of superimposed bedforms decreases along the host‐bedform lee slope, leading to a systematic downstream increase in the sediment accumulation rate relative to bedform celerity. This increase in local bedform climb angle results in the preservation of a larger fraction of formative bedforms. Our results highlight the need to revise current paleohydraulic reconstruction models, and demonstrates that fluvial morphodynamic hierarchy is a fundamental determinant of sedimentary strata. Plain Language Summary: Dune evolution in rivers creates inclined layers of sediment, called cross strata, that are an integral part of the rock record on Earth and Mars. The thickness distribution of cross strata is the primary means of estimating ancient flow and sediment transport conditions. Dunes exist with larger‐scale features, such as bars and larger dunes, in rivers, where a train of dunes responds to flow steering by larger‐scale features through changes in dune size and speed. However, we currently lack data to assess the influence of larger‐scale features on dune evolution and cross strata. Here, we studied dune evolution on the lee side (downstream facing slope) of a larger bedform in an experimental channel, where flow expands and slows down. Using high‐resolution data, we show that the dune size and speed decrease with downstream distance along the host‐bedform lee side. The rate of sediment build‐up relative to dune speed increases downstream, which leads to the preservation of a larger fraction of dunes in cross strata. Results suggest that cross strata preserved in the presence of larger‐scale features are common in the rock record, and we need to revise our current models for estimating past flow conditions from cross strata. Key Points: We characterize bedform evolution and cross strata preservation in a zone of flow expansion and deceleration in a physical experimentBedform size and celerity decrease along the host‐bedform lee slope, causing an increase in aggradation rate relative to bedform celerityA larger fraction of the formative bedforms is preserved as cross strata than typically assumed by paleohydraulic reconstruction models [ABSTRACT FROM AUTHOR]

Stratigraphic positions and the nature of some breccias and mudstones observed in the Lower Cretaceous McMurray Formation type section (Alberta, Canada) challenge the existing fluvial point bar facies models. The currently applied large‐scale, tidally influenced, sandy bedload facies model suggests that point bars fine upward, where breccias and cross‐strata occur at the base of the succession and mud content increases upward. Instead, this study documents that: (i) mudstone clast breccias are not exclusively associated with basal channel‐lag deposits and can occur throughout the point bar; and (ii) stratified mudstones are not limited to the top of the fining‐upward succession and can occur at or near the channel base. This outcrop data, including lithology, sedimentary structures, trace fossils, bed thickness and boundaries, and the nature of stratal packages, further suggests dynamic interplay between fluvial and tidal processes. This article discusses the potential role of high‐magnitude river floods in temporarily elevated suspended sediment concentrations and highlights that fluid mud processes played a crucial role in mud deposition in both tide‐influenced and fluvial parts of the system. Fluid mud processes allowed mud deposition along the channel base and across the point bar accretion surfaces. The breccias predominantly consist of broken pieces of inclined heterolithic strata and mostly occur on accretion sets of point bars, suggesting erosion and collapse of the point bar rather than of the cutbank. This work introduces a novel perspective to the existing models of point bar sedimentation, offering a new end member and concepts for the interpretation of subsurface data. The authors hope that this research encourages further investigations into similar phenomena elsewhere in the world. [ABSTRACT FROM AUTHOR]

Located in the eastern Paleo-Tethys Ocean and near the equator, carbonate sedimentation widely developed in the Sichuan Basin in the Permian Guadalupian period. Although the growth and decline of carbonate particles are closely related to the surrounding sedimentary environment, the relationships between the grain composition and distribution of the northwest Sichuan Basin and the sedimentary environment are not clear. This study explored the particle type, particle content, and sedimentary structure of 300 thin sections from 19 wells and seven field profiles of the Guadalupian period in the northwest Sichuan Basin, identified seven microfacies and four microfacies associations, analyzed the sedimentary environment, and established a sedimentary evolution model. The results show that there was a warm-water Dasycladaceae-dominated and foraminifera-dominated open platform developed in the early Roadian era in the research area. As the climate cooled during the late Roadian era, the warm-water carbonate sedimentary environment was replaced by a cold-water bryozoan-dominated and echinoid-dominated marginal sedimentary environment. As the climate continued to cool and the sea level dropped, the platform margin grain beach sediment underwent further development in the early Wordian era. In the late Wordian era stage, the sedimentary environment was influenced by the Dongwu movement, resulting in sea level changes and acidification caused by hydrothermal activities, which reduced the degree of grain beach development. During the Capitanian era, the climate became warmer due to the eruption of the ELIP. The uplift caused by the Dongwu movement resulted in a relative shallowing of the platform margin region, and hence, the grain beach sediment only developed in the southwest, while the northeast was dominated by deepwater basin sediments. The sudden transition from a warm-water, autotroph-dominated carbonate open platform to a cold-water, heterozoan-dominated carbonate platform margin resulted from a combination of tectonic movements, rapid sea level changes, and sedimentary environment changes during the Guadalupian era. [ABSTRACT FROM AUTHOR]

Diagenetic spheroids are rounded mineralised structures in sedimentary rocks that span several orders of size dimensions. These objects include rosettes spanning tens of micrometres; millimetre-sized granules; and centimetre- to metre-scale botryoids, nodules, and concretions. Connections between diagenetic spheroids and chemically oscillating reactions (COR) have been established based on chemical and pattern similarities. Nevertheless, it is unknown if there are variations in their occurrences throughout geological time, especially during periods of global environmental change. This is because COR are pattern-forming reactions where carboxylic acids are decarboxylated by strong oxidants like sulphuric acid, bromate, or iodate. The hypothesis is that there should be a greater number of diagenetic spheroids at periods of increased atmospheric and oceanic oxygenation levels. Hence, this work presents the first compilation of occurrences of diagenetic spheroids between 0.541 and 1.8 billion years ago (Ga). The compiled patterned objects are those with concentric laminations and radially aligned crystals, which are patterns akin to equidistant circularly concentric waves that radially diffuse in COR. Another characteristic of diagenetic spheroids, similar to that found in botryoidal minerals, is the destructive interference that forms circular twins; this is identical to the COR pattern formed when circular waves meet. The timeline of Proterozoic diagenetic spheroids produced in this work reveals a significant increase in occurrences across the Ediacaran, which is attributed to an increased environmental oxidation state. During this interval, seawater is known to have become richer in sulphate and iodate, which create ideal conditions for the abiotic and diagenetic oxidation of biomass. Therefore, increased occurrences of diagenetic spheroids in the Neoproterozoic possibly represent sedimentological evidence for abiotic decarboxylation reactions and widespread COR in productive environments. The distribution of diagenetic spheroids observed during the Proterozoic may also be more broadly applicable to other epochs of Earth's history. [ABSTRACT FROM AUTHOR]

Extensive, new outcrops along the MT‐100 state road in the northern part of the central uplift of the 40‐km diameter, 252–259 Ma old Araguainha impact structure, Central Brazil, have become available for investigation. They offer new insight into the contact relationships between the different lithologies and the genesis of different types of impact‐related rocks, as well as the current level of erosion of the structure. Three types of impact melt rock (IMR) with different field relationships and compositions can now be distinguished: (1) Type‐I of granitic composition and occurring mainly as veins and dikes, besides a few larger pods, in the central alkali granite core of the central uplift; (2) Type‐II in the form of plastically deformed clasts of mainly highly silicious compositions in polymict impact breccia; and (3) Type‐III, derived from partially melted conglomerate or sandstone precursors, and that occurs at selected sites in (meta)sedimentary strata of the basement in the immediate environs of the alkali granite core. Both polymict lithic and melt‐bearing (suevitic) impact breccias are recognized in the 110‐m thick integrated section through impact breccia directly overlying the crater floor. This crater floor is composed of (meta)‐sedimentary basement strata with granite injections and, locally, sandstones of the Devonian sedimentary Furnas Formation of the Paraná Basin. Main breccia components are (meta)‐pelites and (meta)sandstones of the basement that is currently favored to be related to the regional Paraguay Belt and to the lower sequence of the Paraná Basin sedimentary strata. Locally, breccia contains clasts of IMR Type‐II, and only very rarely are granitic fragments observed. Clasts of IMR Type‐I have never been observed in the breccia deposits. These new observations preclude significant involvement of alkali granite in the formation of the polymict breccia or in the production of shock melts. They also reveal the major role of the (meta)sedimentary precursors in the production of IMR by shock melting and provide essential information for better understanding the cratering processes involved in the formation of an impact structure in a sedimentary target, of the size of the Araguainha impact structure. [ABSTRACT FROM AUTHOR]

Salt diapirs dominate the structure in many sedimentary basins and control the preservation and migration of hydrocarbon. The formation of salt diapirs generally falls into two endmember models: active (up-building) and passive (down-building) diapirism. In the active model, salt diapirs rise from salt buoyancy to pierce through the sedimentary overburden, whereas in the passive model, salt diapirs result from differential loading of sediments during deposition. These endmember models are mostly conceptual or kinematic, the mechanics of active and passive diapirism and their relative roles and interactions in the formation of salt diapirs remain uncertain. Here, we use two-dimensional high-resolution numerical models to investigate the primary factors and critical conditions for active and passive diapirism. Our results indicate that it is improper to use driving mechanisms to classify salt diapirs, because the buoyancy-driven active salt diapirism involves differential loading, while the passive diapirism requires salt buoyancy. The rise of salt diapirs is more sensitive to the effective viscosity of the overburden than to the salt viscosity. Stiff overburdens could prevent the rise of salt diapirs, but they could be pierced by salt diapirs if plastic yield of the overburden is allowed. During deposition, the coupled salt-sediment deformation, driven by both salt buoyancy and differential loading of sediments, can lead to various diapiric salt structures and minibasins. Regional tectonic stress generally promotes salt diapirism by enhancing strain weakening of salts and overburdens. We suggest that the classification of active and passive salt diapirism is an oversimplification in most cases. We propose a general model of the formation of salt diapirs that usually begins with dome initiation driven by salt buoyancy, followed by syndepositional down-building controlled by sedimentation and differential loading and ends with canopy formation when sedimentation stops. [ABSTRACT FROM AUTHOR]

Coastal sediment stratigraphies, their physical properties and microfossil assemblages are commonly used to reconstruct sea-level change. However, coastal sediments are affected by tidal, wave, aeolian, and overwashing processes at a range of elevations both within and above the tidal frame which means that their sea-level signatures may not always be clearly identified. Saltmarsh is a common coastal sedimentary environment along the Atlantic-facing coastline of northwest Ireland where bedrock headlands and an archipelago of small offshore islands have provided accommodation space for aggradational Holocene sediment sequences. A 2.85 m-long sediment sequence was investigated at Cloughglass, northwest Ireland. This shows weathered granite bedrock overlain by glacigenic cobbles and then in situ Pinus stumps within humified peat that is exposed in the upper foreshore. Above this, organic-rich and laminated saltmarsh sediments are arranged in packages (20–80 cm thick) bounded by undulating erosional surfaces. The saltmarsh sediments are unconformably overlain by a palaeosol (30 cm thick) and 1.5 m of recent dune sand. Sediment samples were removed at 5 cm intervals through the entire logged section and analysed for grain size properties, combustible organic content, CaCO 3 content, and microfossil assemblages. Five samples were dated by the AMS 14C method. Results show organic sediment accumulated around the pine tree stumps at ∼4400 cal yr BP but that later sedimentation was episodic, as evidenced by erosional surfaces throughout the saltmarsh part of the succession that may correspond to episodic storms or flood events. Three microfossil biostratigraphic zones are identified which broadly correspond to the sediment stratigraphy. The lowermost zone has poor preservation. The middle zone contains several halophytic species in low abundance but is dominated by the ubiquitous diatom Achnanthidium minutissimum. The uppermost zone is less diverse, with low but consistent abundance of predominately freshwater species and those that can tolerate brackish conditions. Integrating these results suggests that late Holocene coastal erosion and sea-level rise brought the coastline closer to the site over time, with a concomitant increase in wave and tidal influence as recorded in both sedimentary structures and biofacies. Subsequently, the land surface became stabilized with development of a dune palaeosol and decreased abundance of A. minutissimum. This evolutionary history reflects changing patterns of wave exposure and sediment supply as a result of changes in sand accumulation around the surrounding bedrock islands. Thus, the coastal stratigraphy more strongly reflects local sediment dynamics and accommodation space rather than regional sea-level change in the late Holocene. [ABSTRACT FROM AUTHOR]

The Permian Fengcheng Formation (P1f.) in the Hashan area, situated on the southwestern margin of the Junggar Basin, has witnessed a remarkable breakthrough in shale oil exploration in recent years with nearly 789 million tons of shale oil resources. As a unique set of mixed sedimentary shales, the Fengcheng Formation in the Hashan area is characterized by mixed sedimentation of terrigenous siliciclastic sediments, authigenic minerals, and tuffaceous materials. However, the understanding of pore characteristics in the mixed sedimentary reservoir still remains limited, prohibiting accurate estimation of the oil content and insights into oil mobility. Scanning electron microscopy (SEM), X-ray diffraction (XRD), mercury injection capillary pressure (MICP), nuclear magnetic resonance (NMR), X-Ray Computer Tomography (X-CT), and geochemical analysis were performed to investigate the pore size distribution and main controlling factors of the mixed sedimentary reservoir. Results showed that the main pore types in the mixed sedimentary reservoir are intergranular pores and dissolution pores. The pores of the P1f. mixed shales in the Hashan area were classified into II-micropores (< 25 nm), I-micropores (25–100 nm), mesopores (100–1000 nm) and macropores (> 1000 nm). In general, the mixed sedimentary rocks of P1f. formation feature few macropores but a large number of micropores and mesopores. The CS exhibits the most favourable physical properties among all lithofacies. It is concluded that the abundance and maturity of organic matter, mineral composition, sedimentary structure, and diagenesis of reservoir together impact the pore structure in the mixed sedimentary reservoirs. The maturity of organic matter and the content of tuffaceous minerals are the most significant in influencing the pore structure of P1f. shales. Overall, the pore structure of complex lithologic reservoir formed by mixed deposition and its influence on physical properties are studied, and the characteristics of the microscopic pore-throat system of the dominant lithofacies in the Hashan area are clarified, which is of great significance as a guide for the exploration and development of mixed sedimentary reservoirs in continental shale oil in China. [ABSTRACT FROM AUTHOR]

Lake Salda, a terrestrial analog for the paleolake in Jezero Crater on Mars, hosts active, subfossil, and fossil hydromagnesite microbialites, making it an ideal location to study microbialite formation and subsequent processes. Our understanding of this record is still limited by an incomplete knowledge of the macro‐ and mesoscale morphotypes of microbialites, along with their spatial distribution and correlation with microbial and geochemical processes that influence microbialite formation. In this study, we investigated the spatial distribution, morphotypes, mineralogy, geochemistry, and microbial diversity of the microbialites and identified six distinct zones (Zone I to Zone VI) with major microbialite build‐ups in Lake Salda. Newly identified microbialites were classified based on the macro‐ and mesostructures. Our work shows that the lake contains stromatolites, thrombolites, stromatolitic thrombolites, dendrolites, and microbially induced sedimentary structures. At macroscale, Lake Salda microbialites exhibit hemispheres, stacked domes, and laterally linked columnar structures while minicolumns, knobs, mesoclots, laminae, and botryoidal structures are common at mesoscale. The macro‐ and mesoscale distribution of different microbialite types spatially correlates with microbial community composition and water depth. Deep‐growing microbialites with a low abundance of Cyanobacteria (∼1%–4%) and high abundance of Firmicutes (28%–93%) exhibit steeply convex lamination, producing finger‐like minicolumnar mesostructures. In contrast, shallow‐growing microbialites with a low abundance of Firmicutes (0%–5%) and high abundance of Cyanobacteria (11%–37%) have well‐preserved gently convex millimeter‐scale lamination, resulting in cauliflower mesostructures. Palygorskite ((Mg, Al)2Si4O10(OH)) is identified in the diatom‐rich microbial layer of the deep‐growing microbialites. Regardless of the microbialite types, hydromagnesite and aragonite are present in the extracellular polymeric substance (EPS)‐rich zone of the shallow and deep‐growing microbialites. Overall, environmental changes (e.g., water depth and, accommodation space) play a major role in the formation and spatial distribution of different microbialite morphologies at the macro‐ and mesoscale. Differences in the relative abundance of dominant microorganisms between mesostructured types suggest that mesomorphology may be influenced by changes in microbial diversity. Spatial variations in the microbialite morphotypes, along with the abundant presence of entombed biomass (e.g., mineralized filaments), may indicate areas that have a high potential for the preservation of biosignatures. [ABSTRACT FROM AUTHOR]

The age and dolomitization processes in the Paleo-oil reservoir zone, which is composed of massive dolostones found in the Qiangtang Basin (SW China), are still debated. In this research, the Long'eni-Geluguanna Area was selected. Macroscopic information, thin sections, and geochemical methods were used to investigate the dolomitization characteristics and the processes that controlled dolomitization. Five types of replacive dolomites and two types of dolomite cement were observed. Some of the dolomites displayed ghosts of primary sedimentary structures. Saddle dolomites were prevalent, occurring in the interparticle and moldic pores of the limestone which should have been filled at an early diagenetic stage. Ten microfacies types were identified. The foraminifera assemblage provides evidence that the studied interval is of Early Jurassic age. The δ13C values are similar to the contemporaneous seawater signature. The REE+Y patterns of limestones and dolostones exhibit similarities to that of seawater. The mean Na and Sr values are comparable to those of other near-normal seawater dolomites. The δ18O values of all lithologies are markedly depleted. The dolomitization started penecontemporaneously, with deposition. A general sand shoal setting with patch reefs developed. The dolomitizing fluids, near-normal seawater, was probably formed by slight evaporation on top of the shoal. Saddle dolomites in the interparticle and moldic pores might indicate hydrothermal activity, which also caused the recrystallization of some pre-existing dolomites. The recrystallization might have slightly increased the crystal size, demolished the ghost structures, formed saddle dolomites, and altered the REE+Y patterns. The recrystallization extent diminished with increasing distance from the fluids-providing fracture. Furthermore, the existence of protected areas within the sand shoal settings could enhance the vertical and horizontal heterogeneity of dolostone reservoirs. [ABSTRACT FROM AUTHOR]

Oil content and the movability of shale oil are important indicators for the evaluation of continental shale oil. In recent years, the sandwiched shale oil in the fourth member of the Shahejie Formation in the Liaohe Western Depression area of the Bohai Bay Basin has shown great exploration potential, while the understanding of shale oil content and the movability of shale oil is weak. In this study, through a combination of core observations and experiments, we clarified the shale lithofacies types in the fourth member of the Shahejie Formation in the Liaohe Western Depression and explored the influencing factors of the characteristics in the oil-bearing and movability of shales in different lithofacies. The results of the study show that the organic matter content of the shale is high (TOC = 2.2–4.3%), but the maturity of thermal evolution is low (Ro = 0.38–0.55%), and the mineral component is dominated by clay minerals (30.3–72.7%), with quartz, feldspar, and other feldspar minerals developing secondarily. According to the content of organic matter, the mineral component, and the sedimentary structure, five types of lithofacies can be classified: organic-rich laminated clay-bearing felsic shale lithofacies (LS1), organic-rich laminated clay felsic mixed shale lithofacies (LS2), organic-rich layered clay felsic mixed shale lithofacies (LS3), organic-containing massive felsic-bearing clay shale lithofacies (LS4), and organic-containing massive clay felsic mixed shale lithofacies (LS5). The oil content of shale is mainly affected by the organic matter. The rate of increase in oil content of shale is fastest when the organic matter content is between 2 and 4%. The movability of shale oil is mainly controlled by the sedimentary structure, mineral component, and microscopic pore structure; the more the shale laminae is developed, the lower the clay content is, and the more the pore space is developed, the better the movability of shale oil is. Combined with the results of the shale oil content and mobility analysis in the study area, LS2 and LS3 are the dominant lithofacies in the fourth member of the Shahejie Formation in the study area, followed by LS1 >LS5 >LS4, so shale oil exploration should focus on the development of LS2 and LS3. [ABSTRACT FROM AUTHOR]

The accurate determination of rock elasticity modulus is crucial for geomechanical analysis and reliable rock engineering designs. Traditional experimental methods have limitations in estimating elasticity modulus, prompting the adoption of artificial intelligence and data-driven techniques to develop adaptive and accurate predictive models. This study utilized the Deep Random Forest Optimization (DRFO) algorithm, a hybrid approach combining deep learning and random forest algorithms, to predict rock elasticity modulus. The dataset consisted of 350 sedimentary rock samples from various regions in Iran, including sandstone, limestone, marlstone, and mudstone. The performance of the predictive models was assessed using confusion matrices, statistical errors, and the coefficient of determination (R2). The results revealed the superior performance of the DRFO model, exhibiting a remarkably low Mean Absolute Error (MAE) of 0.180 GPa, outperforming other models. The Mean Squared Error (MSE) and Root Mean Squared Error (RMSE) values (0.026 and 0.161, respectively) confirmed the precision of DRFO's predictions. DRFO demonstrated robustness and generalization capability, yielding excellent performance in both training and testing datasets. Moreover, accuracy and precision evaluation in the training dataset showed a high accuracy (0.97) and precision (0.97), indicating the reliability of DRFO in estimating rock elasticity modulus. The study underscores the significance of data-driven techniques, particularly the potential of DRFO in accurately predicting rock properties. It contributes valuable insights to the field of geotechnical engineering, aiding infrastructure design and ensuring the safety and stability of sedimentary rock-based structures. Further research can explore DRFO's adaptability to different geological contexts and extend its application to other essential rock properties, advancing geotechnical and geological engineering practices. The integration of advanced data-driven approaches like DRFO can enhance rock mechanics understanding, facilitating sustainable engineering solutions for various geotechnical projects. [ABSTRACT FROM AUTHOR]

Intraplate earthquakes induced by anthropogenic fluid injection present unexpected seismic risk to previously quiescent or low seismicity-rate regions. Despite many studies of induced seismicity, there are relatively few with detailed openly accessible constraints on the interaction between seismic sources and subsurface structures. In this study of the Raton Basin, we refine source observations from a dense nodal array and constrain basin structure using teleseismic receiver functions. The cross-correlation-based relocated hypocentres and a new set of focal mechanisms light up active fault segments and show clear spatiotemporal patterns. The geometric complexity of reactivated fault clusters appears greatest near higher rate injection wells. Simpler normal fault structure is found farther from injection wells and near abrupt structural transitions suggested by receiver functions. While less induced seismicity in the crystalline basement is expected when injection is >1 km from the top of the basement (like Raton), our receiver function analysis identified a basin thickness ~3 km beneath the nodal array and lateral variations in sedimentary structures. Our results explain potential fluid connectivity between the injection depths focused at ~1–1.5 km below the surface and basement fault activity that begins at ~3 km and reaches peak activity at ~4–8 km depths. This article is part of the theme issue 'Induced seismicity in coupled subsurface systems'. [ABSTRACT FROM AUTHOR]

The structure of the post-Caledonian sedimentary cover in the transition from the Precambrian to the Paleozoic platforms in the Polish sector of the Baltic Sea is a matter of ongoing debate due to the sparsity of quality seismic data and insufficient well data. The new high-resolution BalTec seismic data acquired in 2016 contributed greatly to deciphering the regional geology of the area. Here we show an optimal seismic data-processing workflow for the selected new BalTec seismic profiles offshore Poland, as well as legacy PGI97 regional seismic data. Due to the acquisition in a shallow-water environment, the processing strategy focused on suppressing multiple reflections and guided waves through a cascaded application of modern multiple elimination approaches. We illustrate the potential of the new and re-processed data for focusing seismic interpretation on the area of the Koszalin Fault. In light of the available data, the Koszalin Fault was the main structure controlling Mesozoic subsidence and Late Cretaceous–Paleocene inversion of the eastern portion of the Mid-Polish Trough offshore Poland. The inversion changed its character from thin- to thick-skinned towards the north, away from the Polish coast. The Koszalin Fault reactivated older structural grain inherited from the time of Devonian continental rifting at the margin of Laurussia. The fault runs obliquely to the Caledonian Deformation Front, the feature that remained inactive since its formation at the Silurian–Devonian transition. [ABSTRACT FROM AUTHOR]

It is the first time that the fossil footprints of a group of Middle Eocene elephant ancestors have been discovered in the Gonjo Basin, East Tibet Plateau. The Gonjo Formation is attributed to the Middle Eocene Epoch (U-Pb age = 44.7 ± 1.2 Ma) and consists mainly of purplish-red, medium- to coarse-grained sandstones, siltstones interbedded with mudstones, and conglomerates with sedimentary structures like ripple marks, rip-up clasts, and trough-cross bedding, suggesting fluvial-lacustrine systems. The group of fossil footprints has a characteristic oval-concave shape, and the toe impressions are absent. Some fossil footprints are overstepped with a pockmarked texture resembling Proboscipeda enigmatica. More than 165 fossil footprints of the group are relatively well-preserved with different diameters, which is evidence of highly social behavior and trackmakers of different ages, including calves, juveniles, adolescents, and adults. The size frequency of the fossil footprints enabled us to deduce the body mass, shoulder height, and hip-height distribution of the trackmakers that crossed the East Tibet Plateau 44.7 Ma ago. The trackmakers comprised an estimated average hip-height of 111.8 cm, an average shoulder height of 172.8 cm for males/155.9 cm for females, and an average body mass of approximately 1 218.1 kg for males/907.8 kg for females. The abundance of fossil footprints reveals that in the Middle Eocene Epoch, the environment was extraordinarily conducive for the elephant ancestors to live in the East Tibet region. [ABSTRACT FROM AUTHOR]

The Young's modulus and Poisson's ratio determined for the rocks under uniaxial or triaxial loading conditions represent necessary input parameters for solving many geotechnical tasks. However, these effective stiffness moduli, particularly the Poisson's ratios, measured on different samples sometimes substantially differ, even for visually compact and macroscopically homogeneous rock. This has been observed for Brenna sandstone, especially under conditions of conventional triaxial extensions. The aim of this study was, thus, to reveal differences in rock structure that could cause such behavior. Several complementary methods were used to investigate the structure of this sandstone: X-ray computed tomography (CT), visual analysis using optical scanning and stereo-microscopy, and a new method combining water jet erosion with these visualization techniques. Analyses of this structure revealed mechanically more resistant compact thick and adjacent thin weak layers. In rock samples, these layers have different patterns and orientations. To demonstrate the influence of layer orientation on effective stiffness moduli measured under different loading conditions, FEM calculations were performed for idealized structural models. The outcomes of this numerical analysis are in qualitative agreement with the results of the loading experiments and the layered structure revealed in the samples. The ability of the proposed method using water erosion to analyze the rock structure in detail was verified. The method offers an interesting alternative to standard visual and X-ray CT techniques. The numerical calculations indicate the importance of latent layered defects in sedimentary rocks for fine measurements of stiffness moduli (especially the Poisson's ratios) used as inputs for geotechnical applications. Highlights: Rock structure related to stratification has been analyzed by complementary methods. X-ray computed tomography revealed the irregular layered structure of the sandstone. A new method using water jet erosion of the rock surface confirmed the layers. Higher X-ray absorbance approximately corresponds to a higher mechanical resistance. A numerical model of the layers explains the differences in mechanical parameters. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of shoreline change is essential for efficient coastal management. This research provides a thorough analysis of the long-term changes to the shoreline in the Tamil Nadu district of Tirunelveli, India, spanning five decades (1972–2022). Remote sensing techniques and digital shoreline analysis techniques were employed to investigate the temporal variations and underlying mechanisms influencing shoreline dynamics. Remote sensing methods include satellite imagery analysis, digital shoreline analysis techniques involve GIS-based mapping and measurement of coastal features. The statistical methods like EPR, LRR and NSM techniques were used in this study to identify the shoreline changes. It considers the sedimentary structures of tidal flats and grain size investigations in the region to improve our comprehension of the geological characteristics and sediment dynamics driving shoreline alterations. The findings demonstrate how the shoreline location at Koodankulam changed considerably during the course of the research. This study report spans a sizable length of time and provides significant insights on the long-term behaviour of the Tirunelveli district coastline. Sedimentary structures and grain size investigations provide insights into erosion, deposition patterns, and sediment transport, crucial for understanding shoreline dynamics. The three primary very high erosion hotspots in the research area are Kunjanvilai, Koodankulam, and Kuttam. At a rate of − 23.5, − 23.6, and − 23.6 m/year, maximum erosion is shown by EPR, LRR, and WLR. This study outcomes major two regions like Vijayapathi and Anjugramam are facing more accretion zone. A maximum of 13.33, 11.14, and 11.14 m/year is shown by EPR, LRR, and WLR. According to projection research, the spans will measure 60.67 km in 2042 and 59.62 km in 2032, respectively. [ABSTRACT FROM AUTHOR]

The terrestrial heat flow and lithospheric thermal structure of sedimentary basins are crucial for understanding basin dynamics and assessing geothermal resources. This study computed the heat flow in the Hubao Basin using rock thermal conductivity and borehole temperature data. Combined with the geophysical profile of the Yinshan Orogenic Belt–Hubao Basin–Ordos Basin, the lithospheric thermal structure was studied, and the geodynamic mechanism is discussed. The results indicate that the heat flow in the Hubao Basin ranges from 64.0 to 73.8 mW/m2. The Moho temperature along the profile varies between 570 and 652 °C, and the thickness of the thermal lithosphere ranges from 122.7 to 138.8 km. Using the backstripping method to calculate the crust–mantle heat flow ratio, we find that this ratio in in the Hubao Basin is approximately 1, indicating a "warm crust, warm mantle" type of lithospheric thermal structure. This is related to the combined effects of extensional tectonics since the Late Jurassic and Early Cretaceous, westward subduction of the Pacific Plate, remote effects from the Indian Ocean Plate, and the development of deep-seated faults within the basin. The combined effects of lithospheric thinning and deep-seated faults have resulted in thermal anomalies in the Hubao Basin. [ABSTRACT FROM AUTHOR]

The article presents the features of the geomorphological landscape dominated by sand covers and dunes within the inactive middle Warta River valley. Detailed geological and geomorphological mapping, sedimentological analysis and age determinations using 14C and OSL methods allowed their formation to be placed in the late Weichselian/early Holocene and the late Holocene. It was found that the nature of aeolian processes is the result of local aerodynamic conditions, the presence of alluvia and fluvioglacial deposits, and substrate moisture. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) is a relatively new technique in ichnofossil analysis, which permits superior identification of individual trace fossils, their morphology, infill, tiering relationships, and preservation potential, thus providing better environmental interpretations. It also allows non-professional ichnologists to interpret trace fossils in 3D slices with ease, especially in relatively homogeneous and mud-rich sediments. Herein, CT imagery results have been compared with conventional core logging results based on two push core samples from a muddy tidal flat of the Mira River estuary, Portugal. CT images provide a significantly more accurate description of cores and their environmental interpretation due to enhanced visibility of physical and biogenic sedimentary structures. They also reveal complex tiering relationships between burrows with preferential preservation of deeper tiers. The appearance of stacked Scalichnus-like and other siphonichnidal burrows made by infaunal bivalves indicates discontinuous deposition on a tidal flat likely caused by seasonally related fluctuations in an estuarine environment. [ABSTRACT FROM AUTHOR]

The shelf‐margin deltas are the primary 'sources' of interest in siliceous submarine fan source‐to‐sink systems. However, less has yet to be discovered about the roles and effects of the shallow water platform situated on continental slopes. Using the Miocene sediments of the Ledong‐Lingshui Sag in the western part of the Qiongdongnan Basin (QDNB), this paper studies the YC35 coarse‐grained submarine fan that developed in the Meishan Formation (Fm.). The material sources, depositional characteristics, and developmental mechanisms of this fan were investigated. The restored palaeogeomorphology, based on high‐resolution 3D seismic data, shows that a shallow water platform exists. According to geochemical palaeoenvironmental data, the shallow water platform was ideal for forming carbonate deposits in the Meishan Fm., owing to the warm and humid palaeoclimate and the shifting trend in palaeowater depth. Based on the combined source tracing of heavy minerals, coherence slices, and seismic profiles, the shallow water platform and the Ningyuan River source on Hainan Island contributed to the YC35 coarse‐grained submarine fan. Compared to submarine fans formed during different periods, coarse‐grained fan stands out due to its distinct sedimentary structure, rock composition, and microlithological characteristics. Aside from not following the usual Bowmar sequence, there is an excess of gravel and no clear bedding or lamination. A large number of rock fragments, mostly granite and sedimentary rock (carbonatite), make up the rock composition. According to these results, the shallow water platform significantly affects submarine fan material composition. In addition, the attribute slice based on the root mean square reveals that shallow water platforms moderate peripheral deposition. We attribute the development and proximal supply of the shallow water platform to diapirism and forced regression. Our research provides novel insights and comprehension into the investigation of submarine fan sedimentary systems. [ABSTRACT FROM AUTHOR]

This text covers a variety of topics. It begins by discussing a volcanic eruption in southwest Iceland, which has led to the evacuation of the Blue Lagoon spa and the town of Grindavik. The eruption is causing concern due to the large volume of lava flowing towards Grindavik. The text then moves on to discuss a wine grower in Austria who discovered mammoth bones dating back thousands of years, providing insight into how Stone Age people hunted these large animals. In Arizona, a man has opened a museum dedicated to coprolites, or fossilized feces, to educate visitors about ancient creatures. Lastly, China's Chang'e 6 lunar probe successfully landed on the far side of the moon, aiming to collect rock and other material for study. [Extracted from the article]

Alluvial-lacustrine deposits are important carriers for studying paleo-hydrological information and the evolution of paleo-environments. In this study, a total of 6 optically stimulated luminescence (OSL) samples from 2 profiles in the lower and middle reaches of the Hutubi River in the North Tianshan Mountains were dated, and a comprehensive analysis was conducted by integrating sedimentary structures, grain sizes, and magnetic susceptibility characteristics to explore the sedimentary environment patterns and regional evolution processes during the Mid to late Holocene. The results revealed the following findings: (1) The OSL signal of quartz samples indicates the predominance of fast components, allowing reliable dating of regional fluvial sediments using the appropriate condition-tested coarse-grained quartz single-aliquot regenerative dose (SAR) protocol within the 90–125 μm range. (2) Analysis of sedimentary structures, grain sizes, and magnetic susceptibility characteristics reveals lithofacies of heterotopic synchronous or homotopic asynchronous in exposed profiles, with predominantly poorly sorted fine and very fine sand. Magnetic susceptibility is primarily controlled by the content of magnetic minerals in the coarse particles, while also being influenced by the combined effects of provenance input and depositional environment, indicating a complex regional sedimentary environment influenced by variable hydrodynamic conditions driven by fluvial processes. (3) Based on OSL dating results and the analysis of various environmental proxy indicators, it is determined that the climatic environment in the Middle and Late-Holocene in the downstream areas of the northern piedmonts of the Tianshan Mountains demonstrates a fluctuating pattern of wet and dry alternations. The sedimentary environment shifted from a stable state in the Mid-Holocene to an unstable state in the Late-Holocene. The intermittent appearance of wet records may be associated with increased river activity caused presumably by the release of high-altitude ice due to rising temperatures and warming conditions. [ABSTRACT FROM AUTHOR]

Knowledge of the heterogeneity of aquifers caused by sedimentary processes is essential for preferential flow path and flow time estimations due to the spreading of contaminants and ground water protection. Spectral Induced Polarization (SIP) method is a useful geophysical method that can be used to predict hydraulic properties from surface measurements, as there is a close connection between electrical and hydraulic parameters of rocks. Thus, the influence of aquifer heterogeneities such as sedimentary structures on the relationship between SIP parameters and hydraulic conductivity has been subject of some studies and is still an area of interest. In this paper we present the results of laboratory measurements on defined heterogeneous sand samples with the aim to improve the understanding of that connection. More specifically we investigated the dependence of hydraulic conductivity (K ), as well as several SIP parameters like quadrature conductivity ( σ ′ ′ ), in-phase conductivity ( σ ′ ), phase shift (φ ) and chargeability spectra ( m (τ) ), which were calculated by Debye decomposition, on the composition of samples. For the laboratory experiments a measurement cell was designed to carry out hydraulic flow experiments and 4-electrodes SIP measurements on samples in the decimeter scale. The samples consisted of two different sands with different grain size distributions. The two sands were combined in varying volume shares and geometries as well as in parallel and serial orientation relative to hydraulic and electrical current flow. The experimental results show that the SIP parameters and K are clearly dependent on the volume share of the sand components. In terms of preferential flow paths, known correlations to hydraulic conductivity could be reproduced, however the SIP parameters showed no dependency on the orientation of hydraulic heterogeneities. The results indicate that in samples, where the porosity and thus also the electrical conductivity amplitude are approximately homogeneous and only the grain surface area and hydraulic conductivity vary, the mean electrical parameters determined from the SIP data do not provide any information for recognising preferential flow within the scope of the measurement accuracy. [ABSTRACT FROM AUTHOR]

Shallow marine shelf sedimentation is a hot and difficult topic in today's reservoir sedimentology research, and it is widely present in the world. The shallow marine shelf sedimentation is not only affected by complex hydrodynamic effects such as tides and waves, but also controlled by bottom tectonic features, forming a complex and varied sedimentation pattern. During the Middle Jurassic period, the northern part of West Siberian Basin was characterized by a shallow marine shelf sedimentary environment. In the central reion of this basin, a typical tectonic uplift zone developed, forming a tectonic background of "one uplift zone between two depressions". Simultaneously, the dominant influence of tides in the shallow marine shelf environment facilitated the formation of a typical shelf-type tidal delta sedimentation system in the Jurassic strata of the northern part of West Siberian Basin. This sedimentation constitutes a significant natural gas reservoir, and it is important to investigate the sedimentary evolution of shelf-type tidal deltas and to clarify the internal structure and distribution of sedimentary sand bodies and interlayers in shelf-type tidal deltas, which is the basis for the fine development of this type of reservoir. This paper takes the Jurassic strata in the Y region of northern part of West Siberian Basin as the research object, and conducts numerical simulation based on sedimentary dynamics for the shelf-type tidal delta sedimentation formed under the tectonic background of "one uplift zone between two depressions". In addition, tidal amplitude and initial water level were selected for different hydrodynamic factors to study the main controlling factors of shelf-type tidal delta sedimentation. The simulation results show that tidal amplitude is positively correlated with three-dimensional configuration characteristic parameters of the sedimentary sand bodies, and the development of tidal bars becomes more and more limited as the initial water level increases. This paper systematically investigates the sedimentary evolution of shelf-type tidal delta under the tectonic background of "one uplift zone between two depressions" by the sedimentary dynamics method, which deepens the understanding of the shelf-type tidal delta sedimentation process and provides a new thinking for the development of this sedimentary reservoir type (School of Geosciences China University of Petroleum (East China)). [ABSTRACT FROM AUTHOR]

The storm deposition types within the Dabeiwang area of Xuzhou City, Jiangsu Province, China, showcase a wide range of diversity and distinctly apparent characteristics. Based on measured sections and thin-section observations, we have studied the typical characteristics of storm deposition in this area, divided the sedimentary sequence, and summarized a comprehensive model of storm deposition. Various rock types such as thick-bedded dolomitic limestone, oolitic limestone, and calcirudite are developed in the study area. The calcirudite exhibits bamboo leaf-like morphology and various distribution forms. Typical storm sedimentary structures such as scour surfaces and mound cross-bedding were identified in the study area. Based on the distance of the gravel layer from the storm center and the depositional environment, the storm sedimentary sequence in the study area can be divided into allopatric-proximal-lagoon facies storm deposit, allopatric-distal-oolitic shoal facies storm deposit, autochthonous-supratidal facies storm deposit, allopatric-distal-interbeach marine storm deposit, sub-allopatric-tide zone facies storm deposit, and autochthonous-tide zone facies storm deposit. We summarize the comprehensive model of Cambrian storm deposition in the Dabeiwang area of Xuzhou, which has enriched the research results of Cambrian storm deposition in Xuzhou and provides support for the construction of a lithofacies paleogeographic pattern. [ABSTRACT FROM AUTHOR]

The evolution of submarine canyons is primarily controlled by turbidity currents, which erode and fill them over time; however, many other hydrodynamic currents operate within canyons. Bottom currents from these other hydrodynamic processes, including internal tides, can be dominant processes, but their deposits are seldom recognized in sediment cores or the rock record. This study combines autonomous underwater vehicle swath bathymetry imagery and sub‐bottom profiles, high‐resolution sediment core analyses (X‐ray imagery and thin sections), and previously collected seabed video and flow measurements within Logan Canyon head (eastern Canada) to provide a detailed, modern record of facies associated with hydrodynamic processes in a canyon head. These results suggest that bottom currents are responsible for maintaining gullies on canyon sidewalls and an axial channel on the canyon floor. Thin sections of sediment cores reveal that muddy sand in the canyon head consists of mud aggregates and silt and fine‐grained sand, both behaving similarly in terms of flow dynamics. Three facies are present at macro‐scale and micro‐scale: laminated, partially laminated and bioturbated sandy mud. Sedimentary structures include rhythmic sand and mud aggregate couplets, planar to wavy laminations, current ripple cross‐laminations and fining‐upward successions, which are attributed to bottom currents induced by internal tides. Bioturbated facies, characterized by discrete biogenic structures and cross‐cutting relationships, predominate and overprint a mottled background. A mottled bioturbation fabric also alternates with or locally disrupts layering within the partially laminated facies. Internal tide currents, capable of bedload transport and forming ripples, were measured during a monitoring period in the canyon head, followed by rapid re‐establishment of benthos and associated biogenic structures, supporting the core interpretations. Preservation of sedimentary facies associated with these internal tides occurs when the sedimentation rate outpaces the rate of bioturbation, likely during stormier conditions on the shelf. These results represent observations of sedimentary facies associated with modern bottom currents and internal tides, and can be used to interpret similar occurrences within the rock record. [ABSTRACT FROM AUTHOR]