Sedimentary Processes Research Articles

A volcanic and gravity flow controlled fine-grained organic rich deposits of the lower Jurassic Beipiao formation in the Western Liaoning, northeast China

IntroductionThe Lower Jurassic Beipiao Formation in the western Liaoning of northeast China represents a significant case study for understanding the interplay between volcanic activity, sedimentary processes, and organic matter enrichment.MethodsThis study aims to investigate the lithofacies, depositional environments, and hydrocarbon potential of the Beipiao Formation, using core, outcrop, thin-section, and geochemical data.ResultsThirteen lithofacies types were identified, which reflect a complex depositional history influenced by volcanic processes and gravity flows. The sedimentary facies analysis revealed three key depositional environments: shallow lake, semi-deep to deep lacustrine, and fan delta. The basin evolution suggests a transition from fan delta deposits to deep lake deposits and then back to fan delta, with volcanic and gravity flow deposits interbedded. Volcanic activity not only provided nutrient-rich environments conducive to biological productivity but also helped create conditions favorable for organic matter preservation. The earthquake, flooding or stormed events induced gravity flow, which favored plant fragments dispersal to the deep-lake and formed type III kerogen in the deep-lake developed area.DiscussionThese findings suggest that the Jurassic Beipiao Formation in western Liaoning Province, exhibit significant hydrocarbon potential. This challenges previous assumptions regarding the dominance of shallow water environments and limited exploration prospects within the Yanshan Orogenic Belt. Furthermore, this study highlights the crucial role of volcanic activity and gravity flow in organic matter enrichment, transportation, and preservation within a volcanic-rift basin, with potential applicability to similar basins worldwide.

Sedimentary dynamic processes affected by tropical cyclones and anthropogenic forcing in a small-scale estuary: The Sheyang River Estuary, China

Amid the robust landward migration of tropical cyclones (TCs) in the context of global warming, the sedimentary dynamic processes in coastal areas are increasingly affected by TCs. Concurrently, coastal environments face tremendous stress from anthropogenic interventions, such as land reclamation and jetty construction. However, most research puts more emphasis on TC impacts on large-scale estuaries or marginal seas, leaving the sediment dynamics in small estuaries, particularly under the influence of TCs and man-made structures, largely unexplored due to the limited field data. To address this issue, this study took the Sheyang River Estuary (SRE) as an example and explored the sediment dynamic responses to TCs and the jetty construction during Typhoon Lekima in August 2019, utilizing the Finite Volume Coastal Ocean Model (FVCOM). The results showed that the rotating wind field of Lekima induced rapid variations in wave height, residual water level, and currents at different typhoon stages and strengthened the sediment resuspension and alongshore transport. Furthermore, by comparing the effects of Lekima with Typhoon Chan-hom in July 2015, we found that TCs with different tracks produced markedly different dynamic processes, yet all facilitated sediment exchange between the northern and southern areas within the SRE. The study also highlighted the impact of jetty construction on sediment transport during typhoons, noting that jetties can disrupt the typhoon-induced alongshore sediment flux and create eddies on either side by altering sediment advection. In the navigational channel area, the construction of jetties can strengthen the along-channel estuarine circulation during typhoon events, potentially leading to severe channel siltation by trapping riverine sediments and inducing net landward sediment transport. While site-specific, this study provides valuable insights into the combined effects of extreme events and human interventions on sedimentary environments in small estuaries.

Bedform development in confined and unconfined settings of the Carchuna Canyon (Alboran Sea, western Mediterranean Sea): An example of cyclic steps in shelf-incised canyons

Newly acquired high-resolution multibeam bathymetry in combination with sub-bottom acoustic profiles, surficial sediment samples, and three-dimensional flow simulations made possible the characterization of bedforms along the axial channel and depositional lobe of the shelf-incised Carchuna Canyon (Alboran Sea, western Mediterranean Sea). This study aims to describe the erosional and depositional bedforms in confined and unconfined settings of the Carchuna Canyon in order to determine the genetic constraints on sedimentary processes leading to bedform development along the canyon in recent times.The straight Carchuna Canyon, deeply incised in the shelf up to 200 m off the coastline, hosts: (1) crescentic-shaped bedforms (CSBs) that exhibit distinctive crest concavities, asymmetries, and lengths along the axial channel; (2) continuous lateral levees and; (3) a channel bend with three depressed stretches of the levee crest that are less than 20 m high. A set of concentric sediment waves and two scour trails were identified proximal to the channel bend on the open slope east of the Carchuna Canyon. Two distinct acoustic groups consisting of four acoustic units with distinct acoustic patterns were defined along the sediment wave field. The sediment transport simulation shows the highest flow velocities along the Carchuna Canyon thalweg, while along the overbank deposition the highest velocity values occur along the top of the bedform crests, with the higher Froude values being found over the bedform lee sides.The occurrence of CSBs along the canyon axial channel suggests the imprint of confined sediment-laden gravity flows descending from the canyon head and exhibiting a flow variability along the canyon induced by local variations of slope gradient and/or sediment concentration. A spatial relationship is identified between the development of sediment waves over the overbank deposit and lowered levee crest heights at the channel bend. In contrast, more energetic downstream turbiditic flows exceed the levee crest at the channel bend, focusing the overflow and promoting erosion of the overbank deposit, thereby generating the scour trains. Based on the recent history of overbank deposition, two alternating scenarios of flow behavior can be interpreted. In a high-density turbidity current setting, erosion would prevail along the axial channel. Widespread spillover flows of coarse-grained sediments would occur in both levees, forming heterogeneous sedimentary patterns that change downslope within the depositional lobe due to lesser turbulence of spillover turbidity currents and gentler slope gradients. In contrast, in a low-density turbidity current setting, turbidity currents flowing along the Carchuna Canyon would form depositional bedforms in the axial channel, while spillover processes would be localized at the channel bend, forming either depositional or erosional bedforms over the depositional lobe according to the frequency, magnitude and focusing of turbiditic flows.

Hydrogeochemical characteristics and evolution of formation water in the continental sedimentary basin: A case study in the Qaidam Basin, China.

In deep formations, oil or gas reservoir rocks are generally accompanied by groundwater with high total dissolved solids (TDS), commonly referred to as "formation water". The enrichment of trace and/or metallic elements such as K, B, Li, Br, Sr in this type of groundwater holds significant industrial values and socioeconomic benefits. However, the processes involved in the burial and generation of formation water remain not fully understood. In this study, totally 468 sets of major ions and trace elements were collected from current study and literatures to investigate the hydrogeochemical characteristics and evolution mechanisms of formation water from different regional geological structure units in Qaidam Basin, China. The results indicated that TDS of formation water in Western (QW), Central (QC) and Northern (QN) units of Qaidam basin ranged from 173 to 290g/L, 101 to 152g/L and 32 to 73g/L, respectively, which were several to dozens of times higher than those of seawater, but lower than those of intercrystalline brine and salt lake water. The enrichment of Ca, Li, B, Br and depletion of Mg and SO42- were observed in the formation water in comparison to seawater and salt lake water. Formation water especially in QC and QW was identified as typical dissolved brine of terrestrial rock origin, experiencing prolonged water-rock interactions. However, the time and degree of water-rock interaction and metamorphism differed regionally due to the sedimentary history and patterns of Qaidam Paleolake. Overall, the large paleolake deposits under the control of multiple tectonic movements laid the material foundation for the burial and generation of the formation water, and a variety of fluids and deep faults became the sources and migration channels for formation water. It mainly experienced two stages, including the sedimentary process of saline strata and the transformation in the later period.

Groundwater flow system of the Abijata-Langano-Ziway lakes basin, Ethiopia

The Abijata-Langano-Ziway Lakes Basin (ALZLB) is situated in the Central part of the Main Ethiopian Rift. The availability and dynamics of groundwater in the Abijata-Langano-Ziway Lakes Basin (ALZLB) are primarily controlled by its geological and hydrogeological characteristics, shaped by volcanic-tectonic and sedimentary processes. The basin faces significant challenges, including drastic change in land use pattern, rapid population growth sustained by subsistence farming, over-extraction of water resources, and vulnerability to climate change and fragile ecosystems. These issues emphasize the urgent need for effective water resource management.To understand this complex system, a numerical groundwater flow model was employed to characterize the groundwater flow system within the ALZLB and examine its interaction with surface water bodies. The MODFLOW model translates the conceptual understanding of the basin's hydrogeology into a mathematical representation, allowing for numerical analysis. The model incorporates input parameters such as hydraulic conductivity and boundary conditions representing groundwater inflow and outflow. Steady-state numerical calculation was used to characterize the qualitative hydrogeological conceptual model into numerical representation and thereby describe the groundwater system.The calibrated model exhibited excellent agreement between simulated and observed groundwater levels. Statistical measures indicated a strong correlation (R2 = 0.98) and high efficiency (NSE = 0.97) in replicating the observed data. Additionally, the Mean Error (ME) of −8.3 m suggests minimal bias in the simulations. Further analysis of the histogram residuals revealed that a significant portion of the simulated values (65 % and 82 %) fell within ±20 m and ±30 m of the observed groundwater levels, respectively. This revealed the model's accuracy in capturing the groundwater system's behavior.The model identified groundwater recharge and constant head boundaries as the primary sources of groundwater inflow, contributing 445 million cubic meters per year (MCM/year) and 90 MCM/year, respectively. Conversely, constant head boundaries represented the most significant outflow pathway, with a simulated discharge of 519 MCM/year. The calibrated balance between inflow and outflow (discrepancy of −0.75 %) confirms that the model effectively simulates steady-state groundwater flow conditions. The calibrated model demonstrates the model's capability to accurately represent the basin's groundwater system.

Present‐day sedimentary processes on the shelves of inactive volcanic ocean islands: The case study of Porto Santo Island (Madeira Archipelago)

Present‐day sedimentary processes on the shelves of inactive volcanic ocean islands: The case study of Porto Santo Island (Madeira Archipelago)

Holocene pollen records from a large shallow lake in East Asia: Complexity of climate changes, environmental variations, and human activities

The lack of consecutive Holocene sedimentary records in large shallow lakes poses a significant challenge for attaining a comprehensive understanding of long-term correlations among climate and environmental changes, as well as human activity worldwide. This paper presents detailed pollen records from a typical open Lake Baiyangdian which helped to reconstruct multiple environmental processes and human activities in North China during the Holocene, and to detect the complexity of the reconstruction results. The Baiyangdian area experienced a gradual expansion of wetlands since the early Holocene which then transformed into vast delta swamps due to the Holocene transgression of the Bohai Sea. The subsequent regression resulted in the degradation of the swamps and the formation of grassland 6,500–4,500 cal yr BP. The area quickly became a shallow lake after 4,500 cal yr BP, and then gradually expanded with the strengthening of river processes. The relatively warm mid-Holocene climate significantly accelerated the emergence of agriculture, notably the slash-and-burn cultivation after 6,500 cal yr BP, and the continuous intensification of agricultural activities after 4,000 cal yr BP. Human activity became a significant factor of the environmental change in the Baiyangdian Lake region since 2700 cal yr BP. Our results indicate that the Holocene pollen records from large shallow lakes are often complicated by sedimentary processes and human activity, and should be carefully considered when reconstructing past climatic and environmental changes.

Laboratory evaluation of calcareous sand specimens with inclined sedimentary surfaces

Sedimentary processes often produce natural and blown calcareous sands that are deposited in inclined and layered formations. These calcareous sands frequently exist in a complex stress state with rotating principal stress axes that result in intricate mechanical properties. To investigate the mechanical behaviors of calcareous sands with inclined sedimentary surfaces, we developed a device to prepare hollow cylindrical specimens from artificially crushed calcareous sands. By combining this device with a hollow cylindrical torsional shear apparatus, undrained monotonic loading and pure principal stress rotation tests were conducted to investigate the static and dynamic properties of the inherently anisotropic calcareous sands. The results indicate that the shear dilatancy property is related to the principal stress direction; the shear dilatancy of calcareous sand decreases as the direction of the principal stress increases, and the peak stress ratio decreases with increasing principal stress direction and increases with increasing deposition direction. In the precyclic loading period, increases in the deposition direction led to increases in the stabilities of the specimens and decreases in excess pore pressure accumulation, which further affect the dynamic shear modulus and damping ratio of the calcareous sand. In the late stage of cyclic loading, the inherent anisotropies of the specimens are destroyed, so that the excess pressure and hysteresis loop characteristics start to converge.

Deep learning‐based inversion with discrete cosine transform discretization for two‐dimensional basement relief imaging of sedimentary basins from observed gravity anomalies

AbstractSedimentary basins, integral to Earth's geological history and energy resource exploration, undergo complex changes driven by sedimentation, subsidence and geological processes. Gravity anomaly inversion is a crucial technique offering insights into subsurface structures and density variations. Our study addresses the challenge of complex subsurface structure assessment by leveraging deep neural networks to invert observed gravity anomalies. Optimization approaches traditionally incorporate known density distributions obtained from borehole data or geological logging for inverting basement depth in sedimentary basins using observed gravity anomalies. Our study explores the application of deep neural networks in accurate architectural assessment of sedimentary basins and demonstrates their significance in mineral and hydrocarbon exploration. Recent years have witnessed a surge in the use of machine learning in geophysics, with deep learning models playing a pivotal role. Integrating deep neural networks, such as the feedforward neural networks, has revolutionized subsurface density distribution and basement depth estimation. This study introduces a deep neural network specifically tailored for inverting observed gravity anomalies to estimate two‐dimensional basement relief topographies in sedimentary basins. To enhance computational efficiency, a one‐dimensional discrete cosine transform based discretization approach is employed. Synthetic data, generated using non‐Gaussian fractals, compensates for the scarcity of true datasets for training the deep neural network model. The algorithm's robustness is validated through noise introduction with comparisons against an efficient and traditional global optimization‐based approach. Gravity anomalies of real sedimentary basins further validate the algorithm's efficacy, establishing it as a promising methodology for accurate and efficient subsurface imaging in geological exploration.

Biotic aspects of suspended solid reduction in sedimentation ponds

The reduction of suspended solids is an important aspect of water management, especially in the mining industry. The ecological potential of sedimentation ponds has been identified, but many aspects of the coexistence of ecological and technological functions of these reservoirs are still unresolved. The aim of the study was to determine the effectiveness of suspended solid reduction in an open pit mine drainage system under the influence of biotic factors, including fish, taking into account the hydrochemical background. The dynamics of biotic factors and the sedimentation process were identified using the normalized total suspended solid reduction index (TE) and the trophic group status (TGS) indices of planktivorous, benthivorous, and carnivorous fish. The hydrochemical background in both ponds provided similar habitat conditions for biota and suspended solid reduction. Although a moderately trophic ecosystem has developed, the typical relationship between water transparency (SDD) and chlorophyll a concentration characteristic of natural waters was not observed. The sedimentation complex was found to be highly effective in reducing total suspended solids by 89–93%. Spatial variation of sedimentation rates was related to the ichthyobiotic factor, mainly to the biomass of bentophages and the status of this trophic group in the fish community. Stable relationships in the structure of the ichthyofauna with a balanced proportion of planktivorous fishes favored the sedimentation process. The results obtained are part of the development of research on the possibility of combining the technological function of artificial ponds with other applications and ecological benefits for industrialized areas.

Holocene and Reworked Pleistocene Sediments in Mud Depocenters of the Inner Continental Shelf of Sao Paulo Bight (Southeast Brazil)

Mud depocenters are found across most siliciclastic continental shelves, occurring in various bathymetric ranges and typically dating to the Holocene. This study analyzes the sedimentary characteristics and formation processes of mud depocenters in the central sector of the inner continental shelf of the São Paulo Bight. A total of 1700 km of high-resolution seismic profiles, four gravity cores, and 1346 surface sediment samples were analyzed. The sedimentary analysis involved determining grain size parameters, organic matter content, carbonates content, and radiocarbon dating. Seafloor sedimentary mapping shows the predominance of very fine siliciclastic sand, together with three mud depocenters located shallower than the 30-meter isobath. The northern depocenter comprises one sedimentary unit (SU-NZ-01), while the central depocenter consists of two sedimentary units (SU-CZ-01 and SU-CZ-02) and the southern depocenter is made up of two other sedimentary units (SU-SZ-01 and SU-SZ-02). Units SU-SZ-02, SU-CZ-02, and SU-NZ-01 were deposited on Precambrian rock surfaces during the Holocene transgression and include reworked sediments from nearby Upper Pleistocene coastal plains, characterized by a transparent seismic pattern. Above these, units SU-SZ-01 and SU-CZ-01 developed following the Holocene Transgression Maximum, associated with local mud input from the Peruíbe River mouth and the Santos Estuary, respectively. The paleorelief of Precambrian rocks favored the formation of these depocenters by creating wave shadow zones and trapping mud within the paleovalleys.

Quantitative reconstruction of sedimentary processes, provenance, and binary sources in Horqin Sandy Land, NE China: An integrated approach

As the largest semi-fixed dune field in China, the Horqin Sandy Land (HSL) provides a valuable opportunity to study the surface processes and paleoenvironmental evolution of drylands in the monsoon region. However, limited data and a single qualitative approach hinder our understanding of the sediment erosion and transport process of the HSL. The ability to trace and quantify sediment provenance of the HSL is increasingly needed to properly understand the source-to-sink processes, and to accurately interpret aeolian–fluvial interactions in terms of a comprehensive database and multidisciplinary approach perspective. This study integrates previously existing grain-size, heavy mineral, element geochemistry, Sr-Nd-Hf isotopic, and zircon-geochronological databases with new petrographic, TIMA automation heavy mineral data and statistical analysis. Together, the high degree of recycling of HSL severely limits the provenance identification of element fingerprints, although these elements are largely inherited from the parent rocks and are not affected by chemical weathering. The heavy minerals, Sr-Nd-Hf isotopes, and zircon U-Pb age composition together reveal that the HSL sediments are a binary mixture of the Palaeozoic-Mesozoic igneous rocks in the Great Xing’an Range (GXR) and the Precambrian metamorphic rocks in the Yanshan Mountains. The isotopic end-element mixing models, multidimensional scaling (MDS) diagrams and inverse Monte Carlo models of detrital zircon ages indicate that GXR and Yanshan Mountains account for ∼ 60 % and ∼ 40 % of the source contributions, respectively. Under the strong influence of the northwest to west winds controlled by the Mongolia-Siberian High, detrital material from the GXR is consistently transported to the interior of the dune field and intensively reworked. The Laoha River and the Yangxumu River originating from the Yanshan Mountains provide stable detrital sources for the HSL. In addition, the transverse flow of the Xilamulun River and the West Liao River has provided sufficient space and sediment for the dunes, which is conducive to the full mixing of materials inside the dune field. The sediment in the southeast of HSL shows an obvious Yanshan Mountains source dominance and a grain-size dependence. The coarse fractions (>63 μm) mainly modified from the river channel sand and alluvial plain of the Yangxumu River (∼75.8 %), while the fine fractions (<63 μm) have a strong affinity with the loess deposit of Yanshan Mountains (∼52.4 %). The fluvial-lacustrine deposits during the last glacial maximum served as a temporary transit station, providing a direct dust source for the modern dunes in the HSL region. Aeolian–fluvial interaction controls the geomorphology and landscape evolution of the HSL in the monsoon region; however, it is challenging to derive insights into the landscape evolution from studying surface samples.

Aborted oceanic basin during the Mesozoic rifting of the South-Iberian Palaeomargin and interactions with the sedimentation processes

ABSTRACT During the Mesozoic, the South-Iberian Palaeomargin experienced successive phases of extensional tectonics related to the fragmentation of Pangea and the aperture of the Central Atlantic. During the Pliensbachian, the rifting favoured the fracturing and collapse of the Early Jurassic carbonate platform and delimited a subdomain characterized by high subsidence called Median Subbetic (Betic Cordillera, S Spain). The progression of the rifting and the related extension along ~ 102 Ma, from late Pliensbachian to Santonian, favoured the activity of lithospheric scale faulting and extensional basic magmatism in the Median Subbetic with alkaline affinity. The highest volume of lava emissions, represented by pillow-lava flows interbedded with hemipelagic sediments, occurred during the Middle Jurassic. The pillow-lavas show aphanitic texture with Ca-rich plagioclase and clinopyroxene, whereas subvolcanic rocks are aphanitic with high content of plagioclase to phaneritic with plagioclase, olivine and biotite. The rocks present low SiO2 (46.6–53.5 wt.%) and relatively high K2O (locally reaching 8.7 wt.%), and the content of trace elements generally ranges between those from E-MORB and OIB composition. Values of some ratios such as (Gd/Yb)N, (La/Yb)N, (La/Sm)N, and the Nb content increase in the Upper Cretaceous pillow-lava flows, whereas Yb and Y contents decrease, that point to more alkaline affinity. Low Yb and Y contents point to the presence of garnet as residual phase in the mantle source. We interpret that during the early Late Cretaceous, hyperextensional phase of the continental rifting throughout an aborted oceanic basin occurred and allowed lithospheric deeper asthenospheric mantle up-lift and the partial melting. The phases of extensional tectonic controlled the configuration of this palaeomargin in complex tectono-palaeogeographic subdomains, the sedimentary cycles, and the volcanic activity during the Jurassic and Cretaceous. Finally, the transition from passive margin to a convergent one began during the Campanian and no more volcanism is recorded in the Median Subbetic.

Evidences of the sources of suspended sediments and ecological processes in the Yellow River Basin.

Terrestrial originated suspended sediments from the Yellow River are crucial to understand the sources of the suspended sediment and ecological processes in estuary. This study integrated physicochemical indices, stable isotopes and microbial communities to trace the origin of the suspended sediment, and investigated the importance of ecological processes in community assembly via the null model and neutral community model. Global data revealed that the dissolved and particle ratios of carbon and nitrogen obviously decreased from the headstream to the estuary. A significant positive correlation was detected between δ15N and δ13C from Henan Province to offshore. Notable differences in bacterial community composition were found between Henan Province and offshore in dry season, whereas nearly no remarkable changes were detected throughout the entire YR basin in wet season. Multiple lines of evidence from physicochemical analysis, stable isotopic and genetic tracing revealed the possibility that the terrestrially- derived suspended sediments in the lower reaches contributed the most carbon and nitrogen to the suspended sediment in the estuary. Dispersal limitations for stochastic processes had the greatest relative importance in the community assembly of the two seasons. A greater degree of homogeneous selection for deterministic processes was exhibited in dry but not wet season. Proteobacteria had a remarkable correlation with salinity and conductivity in both dry and wet seasons, while Elusimicrobiota was more strongly related to NO3-N in dry than that in wet season. Therefore, this study elucidates the source of suspended sediment in estuaries and highlights the ecological processes involved in altering the microbial community composition in Yellow River basin.

Realtime estimation of average sand grain diameter and sand bed height and mass for a trailing suction hopper dredger

A Trailing Suction Hopper Dredger (TSHD) in the sailing process, excavating seabed sediment with the drag head and pumping it through the pipeline to the spoil hopper sedimentation. The spoil hopper sedimentation process, as a critical factor affecting the loading yield and efficiency of a dredger, is susceptible to the influence of different average sand grain diameter dm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d_{m}$$\\end{document}. However, the soil type tends to change continuously during the loading process, making it difficult to obtain the dm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d_{m}$$\\end{document} by measurement or calculation. In this paper, combined with the existing simplified one-dimensional sedimentation model and simulated loading data, the Bootstrap Particle Filter (BPF), Gaussian Particle Swarm Optimized Particle Filter (GPSO-PF), Assisted Particle Filter (APF), Continuous-Discrete Feedback Particle Filter based on the constant feedback gain approximation (CD-FPF-CG) and the Galerkin method feedback gain approximation (CD-FPF-GL) are applied in the numerical simulations for online estimation of important variables such as the average sand grain diameter dm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d_{m}$$\\end{document}, the sand bed height hs\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h_{s}$$\\end{document} and mass ms\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m_{s}$$\\end{document}, respectively. The simulations results show that the CD-FPF-CG has a higher numerical accuracy and efficiency than the BPF, GPSO-PF, APF and CD-FPF-GL. Therefore, the CD-FPF-CG is used to estimate the above important variables for the actual vessel and the initial value of the average sand grain diameter dm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d_{m}$$\\end{document} for the CD-FPF-CG is determined via Simulated Annealing Multiple Population Genetic Algorithm (SAMPGA).

Brownian dynamics simulation of the structural evolution in monodisperse hard-sphere suspensions during drying and sedimentation processes.

The drying behavior of monodisperse colloidal films, with a focus on the influence of process variables on film microstructures, is explored via Brownian dynamics (BD) simulations. In our model, hard-sphere colloidal particles are dispersed in a Newtonian liquid with an initial particle volume fraction of 0.1. The effects of the drying rate and sedimentation on the evolving microstructures are systematically investigated using two dimensionless numbers: the Péclet number (Pe), which represents the competition between evaporation and diffusion, and the sedimentation number (Ns), which reflects the relative influence of sedimentation on evaporation. First, we analyze the local particle volume fraction and film structure at various Pe and Ns. As Pe increases, particle accumulation occurs near the liquid-gas interface, whereas a high Ns promotes dense packing near the substrate owing to sedimentation. The BD simulation results, viz. the local volume fraction profiles and drying regime maps, are in good agreement with those of the continuum model proposed by Wang and Brady. Structural analysis of the dried films reveals that at a low Pe (Pe = 0.1), a face-centered cubic (FCC) structure dominates, primarily independent of the sedimentation effects. In contrast, a high Pe leads to hexagonal close-packed or amorphous structure formation. Notably, at intermediate drying rates (Pe = 10), an increase in Ns promotes additional FCC ordering in the final film structure. Our study provides new insights into the hitherto underexplored role of sedimentation in the structural evolution of drying colloidal films, revealing the mechanisms of drying-induced assembly in colloidal systems.

Geochemical characterization of humic acids and humification processes in lake sediments of West Antarctica

Geochemical characterization of humic acids and humification processes in lake sediments of West Antarctica

The sedimentology and multi-stage evolution of a Pleistocene esker on soft substratum, a case from North Central Poland

Eskers are one of the meltwater landforms that enable the reconstruction of the nature of subglacial drainage systems. Therefore, they play a significant role in the study of palaeo ice sheets. While the spatial distribution of subglacial tunnels and their geometry resulting from the geomorphological features of eskers are relatively well known, the course and time of sedimentation processes taking place inside the subglacial conduits are understood only to a certain extent, especially in the case of eskers developed on soft substrata. The paper presents an example of an esker that developed on a soft substratum from Central-North Poland, which was formed in several stages. In the initial stage, meltwater drainage took place through a channel that dissected the substratum (N-channel). Its development was associated with intense flow under pressure, but the sediments filling the channel were already deposited under atmospheric pressure when the flow used only part of the available space of the conduit. The high frequency of large-scale, cross-stratified lithofacies indicates significant flow depth and sediment deposition under a lower flow regime. The succession filling the channel resembles the sediments of a low-sinuosity open river systems with varied channel morphology, however, it also contains deposits like the point bar succession. Later, the R-channel developed, dominated by deposition from supercritical flows, probably of a much smaller depth. The sediments were deposited from a traction carpet or a highly turbulent suspension. The massive structure of many lithofacies indicates that flow overload was common. The transformation of the system from N-channel to R-channel was probably related to the decrease in the slope of the ice sheet surface during ablation, which resulted in a reduction of the potential hydraulic pressure gradient. The final stage of esker sedimentation was associated with deposition in an open channel, which indicates the passive nature of the marginal part of the ice sheet.

Assessing the geochemical correlation between petroleum source rocks in the Brazilian Equatorial margin basins and global oceanic anoxic events

This research aims to investigate the correlation between the Cretaceous Oceanic Anoxic Events (OAEs) and the source rocks of the Brazilian Equatorial Margin (BEM) basins. These source rocks, particularly from the Cenomanian-Turonian interval, are known to contain high levels of Total Organic Carbon (TOC) and exhibit significant hydrocarbon potential. The principal focus is on how global anoxic events, such as OAE-1b, OAE-1d, and OAE-2, influenced the depositional environments and organic matter types across the BEM basins, which include Foz do Amazonas, Pará-Maranhão, Barreirinhas, Ceará, and Potiguar. Key results indicate a strong correlation between periods of anoxia and the accumulation of organic-rich sediments in these basins. The Foz do Amazonas Basin features predominantly terrestrial-derived kerogen (Type III), while the Ceará and Potiguar basins show marine-derived kerogen (Type I and II), aligning with global productivity patterns during anoxic events. These variations in kerogen type reflect differences in depositional environments influenced by sea-level changes and nutrient influx. The research concludes that the OAEs significantly impacted organic matter preservation and hydrocarbon generation in the BEM basins. The study's findings contribute to the broader understanding of how Cretaceous OAEs shaped the geochemical and sedimentary processes in equatorial Atlantic margins, highlighting the potential for further oil and gas exploration in these regions.

Emplacement and landscape controls on ancient submarine volcanism: 3D seismic geomorphological analysis of Cretaceous volcanic activity in the Browse Basin, Australian North West Shelf

Ancient submarine volcanic systems preserved within sedimentary basins provide opportunities to investigate the time and spatial distributions of intrusive and extrusive rocks, though existing work has largely focused on the geometrical features of submarine volcanic products, with limited interrogation of their interactions with sedimentary processes. This study investigates a buried submarine volcanic system within the Browse Basin, Australian North West Shelf. Through the integration of three-dimensional seismic reflection survey with borehole data, our study reveals intricate geometric features of a submarine volcano and lava channels, and their relationship to an associated intrusive network of Early Cretaceous age that has been preserved beneath ∼3.5 km of sedimentary overburden. In planform, the volcano has a diameter &gt;4.5 km with a preserved height reaching 650 m. Meandering lava flow channels extend ∼20 km southward of the volcanic edifice, forming lava lobes with pressure ridges at the flow termini. Abundant sheet intrusions, identified within underlying Jurassic and older strata, indicate a magma transport from the north. The localised accumulation of sills led to variations in paleo-seafloor topography, influencing the direction of lava flows and post-volcanic sedimentation patterns. Our findings have a broad range of implications encompassing submarine volcanism and their impacts on basin dynamics.