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• A novel three-equation two-phase flow model is proposed for sedimentation and consolidation. • Fluid pressure increases with initial sediment concentration, necessitating incorporation of non-hydrostatic pressure. • Inertial effects become significant with larger grains, indicating the need to incorporate inertial forces. Sedimentation and consolidation, a multi-physical phenomenon of great significance in aquatic environments, usually involves dynamic pore pressure, inertial effects, fluid-particle interphase interaction and solid stress. However, simplified models for sedimentation and consolidation typically assume hydrostatic mixture pressure and neglect inertial effects without proper justifications. Here, a one-dimensional three-equation two-phase flow model (TTP) is proposed for sedimentation and consolidation, which directly resolves dynamic fluid pressure and inertial terms. The present TTP model is benchmarked against a series of experimental cases and two existing four-equation two-phase flow (FTP) models. It features encouraging performance as compared to measured data and computed results of the existing FTP model. Furthermore, the present TTP model shows superior computing efficiency over the FTP models. To investigate the influences of inertial effects and non-hydrostatic mixture pressure, two simplified versions of the TTP model are constructed and compared with the TTP model. It is shown that incorporating inertial effects and non-hydrostatic fluid pressure are important for accurately predicting the sedimentation-consolidation process. The present study facilitates a promising framework for modelling sedimentation and consolidation, thereby supporting effective sediment management. [ABSTRACT FROM AUTHOR]

The sedimentary infill of the Quibas karstic site (Early Pleistocene, southern Spain) represents the only continuous succession with remains of continental vertebrates in Europe from pre-Jaramillo to post-Jaramillo age. The Quibas site, with a significant paleontological record, is dated between 1.1 and 0.9 Ma and offers a unique opportunity to carry out a paleoclimatic reconstruction of the time period immediately after the arrival of the first humans to western Europe. For this reason, defining the dominant sedimentary processes in the different stratigraphic units and the associated paleoenvironment is essential. The Quibas site is made up of two karstic features with two stratigraphic sequences: Quibas-Cueva, containing six lithostratigraphic units, and Quibas-Sima, which contains seven lithostratigraphic units. The detailed description and analyses of the stratigraphic sections have allowed the characterization of various autochthonous and allochthonous facies of cave deposits. Paleoclimatic proxies, inferred from sedimentological analyses, reveal a record of several alternating humid and arid phases resulting from the Early Pleistocene glacial-interglacial cycles, allowing correlation to the marine oxygen isotope record. The lowermost units (pre-Jaramillo) were deposited during a long-lasting interglacial, correlated to MIS 33–31. It was followed by an increase in aridity in the intermediate units of Quibas-Sima and uppermost unit of Quibas-Cueva (Jaramillo), revealing the beginning of a glacial period at the start of the Jaramillo subchron (1 Ma), which can be correlated to MIS 30. The upper Jaramillo and post-Jaramillo units suggest these were deposited in alternating periods of aridity and humid conditions, although less humid than the pre-Jaramillo period, probably representing the MIS 29 interglacial, the MIS 28 glacial and the MIS 27 interglacial. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) has a nutrient-like distribution in the ocean, similar to the macronutrient phosphate. Significant isotope fractionation induced by the biological cycling of Cd makes it a potential tracer for nutrients and productivity. However, the Cd flux and Cd isotope composition of marine sediments may also be influenced by local redox conditions and partial remineralization of organically hosted Cd. These confounding factors are under-constrained and render it challenging to use Cd as a reliable paleoproxy. To understand the relative importance of each of these processes, we examined the Cd isotope systematics of 69 modern sediments deposited across a wide range of environments. We complement these data with four profiles of particulate Cd isotope compositions from the Southern Ocean. We report three main results. First, we show that the sedimentary flux of Cd is tightly coupled to that of organic matter. Second, most Cd burial occurs in regions with some bottom-water oxygen, and the flux of CdS to anoxic regions is, globally, minor. Finally, we find that remineralization can substantially modify sedimentary Cd isotope compositions, though it is challenging to relate pelagic and sedimentary processes. For example, we find that the relationship between sedimentary Cd isotope compositions and surface seawater [Cd] is the reverse of that predicted by isotope reactor models. Likewise, sedimentary Cd isotope compositions are anti-correlated with bottom-water oxygen. While this pattern is consistent with preferential remineralization of isotopically heavy Cd, profiles of marine particulate matter reveal the reverse, whereby the Cd isotope composition of large particles, which are most likely to reach the seafloor, becomes increasingly 'heavy' with depth. These results highlight how productivity, redox, and remineralization all influence the flux and isotope composition of Cd to marine sediments. While our study suggests that there is no simple way to relate sedimentary Cd isotopes to surface nutrient utilization, our data point toward several potential controls that could form the basis of novel proxies for local redox conditions and remineralization. [ABSTRACT FROM AUTHOR]

Plio-Pleistocene sedimentary successions, comprised of fluvio-glacial-lacustrine sediments capped by loess, are widespread in the Kashmir Valley, NW Himalaya, India. These sediments act as a repository of climate records for the past 4.4 Ma suggesting the dominance of southwestern monsoon up to 1.95 Ma and thereafter the dominance of mid-latitude western disturbances in the region. However, the younger strata of the loess-paleosol sequences (LPSs), <200 ka old, and Holocene sediments have been studied for high-resolution climate records compared to older archives because of the contentious chronological issues of the older deposits. Earlier studies revealed moderate climatic conditions from ∼65.8 ± 7.2 ka to 44.3 ± 5.8 ka, followed by periods of extreme dry phases of enhanced wind velocity, coinciding with the last major magnetic inversion. The climatic conditions have produced strong pedogenic signatures on the LPSs during the MIS-3 (∼43–34.7 ± 2.3). The dry arid climate phases recorded during the MIS-2 stage up to ∼14.7 ± 5.4 ka revealed a weak pedogenic alteration and a high amount of CaCO 3 accumulation in the loess. Subsequent sporadic alluvial deposition of sediments over the LPSs implies widespread precipitation and glacial melting linked to the onset of the Holocene warming punctuated by dry and cold climate phases corresponding to the Bond events of 0, 3, 4, 5, and 7, which indicated a westerly-dominated climate during the Holocene. This review therefore critically examines existing literature on Karewa deposits in the Kashmir Valley, identifies knowledge gaps, and offers recommendations for future research, emphasizing their paleoclimatic potential for the Quaternary Period. [ABSTRACT FROM AUTHOR]

Uncertainty in forming geometric accuracy is one of the main factors limiting the application of Wire Arc Additive Manufacturing (WAAM), highlighting the importance of studying the variation in deposition size. In this paper, the profile of single beads based on CMT technology was studied and a theoretical model was developed to describe the correlation between variable parameters and geometric features. The accuracy of the model in predicting the geometric parameters was verified, and the accuracy errors of the deposition width and deposition height were 7.81 % and 4.82 %, respectively. Then, based on the optimized multi-layer stacking model, an appropriate strategy was proposed to address the phenomenon of layer-by-layer widening due to the changing formation conditions of subsequent sediment layers during the multi-layer single-bead (MLSB) deposition process. The comparative experimental results demonstrated that following the proposed deposition strategy can effectively alleviate this phenomenon and achieve stable deposition geometric parameters. To further verify the stability of the deposition process, six-layer deposition experiments were performed and the actual deposition characteristics of each layer were analyzed, which showed good agreement with the theoretical predictions. The proposed scheme was successful in predicting the sedimentation height with an overall accuracy of 9.4 %. [ABSTRACT FROM AUTHOR]

Aeolian sediments and landforms of the former continental ice sheets' periphery can be used as invaluable sources of information on palaeoenvironmental changes. In the Northeastern Europe, there is very limited knowledge on the structure and age of the aeolian deposits and landforms. This study presents the first data on distribution and chronology of aeolian sediments and landforms in the Vychegda River basin (northeast of the East European Plain). Using grain-size analysis, radiocarbon and OSL dating, we were able to determine the age of the sediments found in the region and study their lithological composition. We discovered aeolian sediments comprising the upper parts of the most river terraces throughout the valley; they come in forms of dunes, dune fields, and sandy or loess-like covers. Previously it was argued that the terraces' upper parts were comprised by glaciolacustrine deposits, but lithological composition of these sediments showed their aeolian origin. It was found that most of the aeolian sediments have formed in the Late Glacial, between 17 and 10.5 ka. We consider that increased fluvial activity and melting of permafrost were the main causes of the aeolian processes activization and that sediment availability was the most important controlling factor during that time. [ABSTRACT FROM AUTHOR]

Evaluating the stratigraphy of the North Pacific is the first step towards understanding the role of this region in climate variability in the past. This region has been notoriously difficult to work in due to the presumed low sedimentation rates (<0.1 cm/kyr), which would likely be inadequate to capture glacial-interglacial cycles of the Late Pleistocene (∼500,000 years). These low sedimentation rates have been estimated from magnetostratigraphy and biostratigraphy, but those techniques are only minimally constrained during this geologically recent time period. Here, we reconstruct average sedimentation rates for the last 500 kyr across the deep (>3000 m) North Pacific using 230Th depth profiling, which is based on the exponential radioactive decay of 230Th and is one of only a few chronological tools applicable to sediment within this relatively calcium carbonate deficient region. Sedimentation rates are indeed low (<0.25 cm/kyr) within the subtropical gyre, especially between 20 and 30°N, but sedimentation rates greater than 0.5 cm/kyr are observed between 30 and 40°N, particularly west of 200°E. Sedimentation rates are higher underneath the Asian dust plume, and no water depth dependence is observed below 4000 m. Sedimentation rates from 230Th depth profiling generally agree with other methods, but they may be more representative of the average sedimentation rates for the last 500 kyr compared to other proxies that operate on much shorter (e.g., radiocarbon) or much longer (e.g., magnetostratigraphy) timescales. Overall, the efficacy of 230Th chronology is a promising tool for further investigation into the history of the North Pacific in the past. [ABSTRACT FROM AUTHOR]

UHT treatments applied to dairy products have been associated with modifications on the proteins' structure that may trigger the occurrence of fouling, sedimentation and/or gelation. These issues are particularly relevant regarding formulated whey protein-rich dairy beverages. In this context, this study aimed to evaluate the impact of a two steps preheating treatment coupled with homogenization (pretreatment) prior to UHT treatment to allow an increase of whey protein concentration in UHT high-protein dairy beverage. The pretreatment was applied to 10% w/w protein formulated beverages displaying casein (CN) to whey protein (WP) ratios of 40:60 and 30:70. The pretreated beverages were compared with non-pretreated beverage containing 50CN:50WP ratio. The applied pretreatment induced the denaturation of around 97.8-99.4% of WP. After UHT treatment, despite the higher concentration of WP, pretreated beverages displayed similar particle size distribution and equivalent or lower sedimentation level than the non-pretreated samples. The present study reveals the potential of the pretreatment for allowing the increase of WP content in UHT treated high-protein beverages. The results reinforce the rationalization of process development as a useful strategy for producing stable high-protein products. [ABSTRACT FROM AUTHOR]

To assess the regional seismicity during the late Quaternary, we studied a well−exposed sequence of Luobozhai lacustrine sediments, 14.5 m thick, near Lake Diexi in the upper reaches of the Minjiang River, eastern Tibetan Plateau. High-resolution geochemical, grain-size, and magnetic susceptibility indicators were then used to obtain a continuous record of the changes in elemental and physical properties within the profile to determine additional seismic events that did not result in soft sediment deformation structures. Rapidly deposited layers with underlying soft sediment deformation structures in the Luobozhai section indicate 18 siliciclastic-enriched sandy sediment fluxes from earthquake-triggered landslides or dust of siliciclastic-enriched clastic materials; isolated rapidly deposited layers (without underlying soft sediment deformation structures) record 17 additional earthquake-induced inputs of detrital material into the lake. Hence, there are a total of 35 seismic events (M ≥ 5.0) recorded within the Luobozhai section, which probably reflects the frequent seismicity of Minjiang fault. Optically stimulated luminescence and 14C dating of the Luobozhai section indicates continuous sediment deposition from 18 to 10.2 ka, and had a mean recurrence interval of approximately 224 years. Heavy mineral analysis shows that event layers and non-event layers have different mineral compositions. This reflects changes in sedimentation pre, during, and post a seismic event, especially the co-seismic debris material (e.g., from landslides and/or dust storms) that controls changes in provenance within the drainage basin, and in turn affects the regional erosion rate and weathering patterns. This study opens up new avenues of paleo-earthquake research. [ABSTRACT FROM AUTHOR]

Chemical engineers frequently contribute to the advancement of the medical field; however, medical applications are often only covered in elective courses. To introduce medical applications into the core curriculum, we implemented a hands-on learning tool that portrays blood separation principles through microbead settling in a core third-year chemical engineering separations class. Test scores from twenty-six students show significant growth at p < 0.001 from Pretest to Posttest I at average values of 41 % and 68 %, respectively. Posttest II scores reveal a significantly higher average score of 84 % for students who sat through lecture before the hands-on experiment in comparison to 75 % for students who first had the hands-on experiment then lecture with statistical significance of p = 0.046 and a moderate Cohen's d effect size of 0.442. Students report positive, lasting impressions from the guided-learning worksheet and hands-on learning experience on their feedback surveys and one-on-one interviews. Retention assessments from four students six months post-intervention reveal retention of concepts with an average test score of 74 %. These outcomes suggest hands-on learning tools are most impactful on conceptual and motivational gains when supplemented with pre-experiment lectures and quality complementary learning materials. A hands-on learning tool containing microbeads suspended in fluid shows blood separation principles and results in significant learning gains in a core chemical engineering separations class. [Display omitted] • Microbeads suspended in fluid are effective in portraying blood separation principles for educational purposes. • Students who experience lecture before the hands-on experiment significantly outperform students who had lecture afterward. • Retention assessments reveal conceptual understanding is maintained six months post-intervention. • Exposure to an interdisciplinary learning tool expanded self-perceived career opportunities for third-year students. [ABSTRACT FROM AUTHOR]

In 2009, South Korea started a large multi-purpose water project on its four major rivers. The main purposes of the Four Major Rivers Restoration Project (FMRRP), which are directly related to water itself, were: (1) securing water resources to combat water scarcity; (2) reducing flood risks by riverbed dredging and reinforcing levees; and (3) restoring the river's environmental functions. Despite socio-environmental opposition, the project was completed in 2011. This article reviews the sedimentation issues raised during and after the FMRRP regarding technological developments and the lessons learned from the project. A total of five sedimentation issues raised directly from the project are reviewed in this article: (1) riverbed dredging and sediment redeposition; (2) tributary headcut; (3) riverbed scour downstream of the movable weir structures; (4) sedimentation management schemes; and (5) a near-prototype river experiment facility. Each issue is addressed by identifying and analyzing field data, developing new numerical models, and testing at a large-scale experiment facility. From this project, we have found that a comprehensive numerical technique is required to predict the sediment issues as mentioned above in a watershed-scale riverwork. [ABSTRACT FROM AUTHOR]

Continuous glucose fermentation produces bioethanol at higher volumetric rates than conventional batch or fed-batch systems. The retention of yeast cells via ultrasonic sedimentation in a lab-scale fermenter allowed for shearless, continuous cell upconcentration, and consequently process intensification. The cell separation efficiency of the ultrasonic system was predicted with a Response Surface Model (RSM) developed for yeast cells based on the linear, mixed, and quadratic effects of the operating variables and flow rates (3 levels, 5 variables). The experiments for the RSM calibration were designed via a central composite design. The efflciency model was validated and showed dependency to the Biomass concentration, Power input, and Harvest rate (R3alibration = 0.92, R~ediction - 0.83). A lab-scale fermenter fed with yeast growth medium was operated at varying dilution rates (0.1 - 0.6 h-1) based on the RSM to maximize the cell retention efficiency (23%-90%). Yeast cell concentration in the fermenter reached up to 31.5 i 0.7 g/L while it remained at around 3 3/L in the harvest stream for all the dilution rates tested. The ethanol concentration ranged between 17 and 23 */L and reached high volumetric productivity (8.8 g/L/h). A control run without ultrasonic sedimentation led to the washout of biomass at a dilution rate of 0.6 h-1. Ultrasonic yeast sedimentation is a promising technology for cell retention and enhanced productivity in continuous fermentation processes. [ABSTRACT FROM AUTHOR]

The Aptian–Albian (A–A) transition encompassed a critical timing in the evolution of Fars Platform (Zagros Basin, SW Iran), such that a number of previous studies on its proximal part (called "Coastal Fars") illustrated platform recovery after sustained demise due to latest Aptian maximum sea-level lowstand. So far, much less attention has been given to the distal part of the platform – "Interior Fars" – where the lack of proper geological age interpretations, in particular, has been limiting a full paleoenvironmental reconstruction of the southern shallower Neo-Tethys. In order to establish the chronostratigraphic framework of Interior Fars, this study presents a novel set of planktonic foraminiferal record for the A–A Kazhdumi Formation at the Saroie section. The identified fauna comprises nine species from four genera, all of which are reported for the first time from Fars Platform. The observed new bioevents are generally consistent with those of the proposed reference section at a deeper intrashelf setting (Tang-e-Maghar, Dezful Embayment), allowing for the establishment of a local upper Aptian–Lower Albian zonation and leading to adequate constraints on the local Aptian/Albian boundary and the timing of prominent black shale deposition (possible "Jacob" equivalent). Based on this new Saroie chronostratigraphic scheme, it is evident that sedimentation across the A–A transition was maintained fully marine at the Saroie section, Interior Fars. This finding does not support the previous inference of extensive subaerial exposure of the entire Fars Platform at that time, thereby calling for a major revision of the published prevailing model for latest Aptian paleogeography of this region. These new insights will facilitate better understanding of the Fars Platform evolution in the Zagros Basin as well as paleoenvironmental reconstructions along the southern Neo-Tethys. [ABSTRACT FROM AUTHOR]

For decades, bioactive glass (BAG) has been utilized as a competent bone substitute owing to its intrinsic properties, such as outstanding biocompatibility and bioresorbability. Stereolithography (SL) is an additive manufacturing technology used to produce highly accurate three-dimensional BAG-based bone substitutes. However, the preparation of BAG-based SL resin is always a challenge, especially because of the inevitable sedimentation of BAG particles. In this study, BAG particles with different sizes were prepared by dry grinding (BAG dry , greater particle size) and wet grinding (BAG wet, finer particle size). Then, BAG dry or BAG wet SL resins with various amounts of surfactant were analyzed. The sedimentation rate for BAG powder increased with increasing particle size but decreased with increasing amounts of surfactant added to the resin. BAG wet SL resins had a longer shelf life, so printing could still be finished after 14 days, whereas BAG dry SL resins were no longer useable after 5 days. However, the BAG particle size did not affect the printing accuracy or scaffold strength. According to our results, BAG-based SL resin fabricated with BAG wet (particle size <1.6 μm) and 5 wt% surfactant exhibited better resistance to sedimentation. [ABSTRACT FROM AUTHOR]

Glauconite mineral is one of the most sensitive indicators of low sedimentation rate in the marine environment. The time of residence of glauconites at the sea bottom before burial is reflected by their so-called maturity that is differentiated based on their K 2 O content. The present work aims to investigate the evolution of glauconites during the transition toward the highly evolved level. Complementary electron microprobe, Raman, and Thermogravimetric analysis were performed on glauconitic grains from the Belluno basin (N Italy) with different K 2 O content in order to verify whether the level of glauconites evolution affects the results of these surveys. The obtained results show that Raman spectra are sensitive to the grade of glauconite maturations. First, spectra of mature glauconites are more structured, due to the lower degree of Al substitution in the octahedral sites. Moreover, the position of the strongest Raman peak (Si–Ob–Si mode) at ∼700 cm−1 shows two contrasting behaviors in the early (K 2 O <8%) and late (K 2 O> 8%) stages of glauconites maturation, respectively. TGA measurements reveals that the presence of interlayer water is also related to the state of glauconites maturations. The obtained results were explained in the light of different isomorphic substitutions occurring at octahedral level in the mature and non-mature glauconites, thus allowing to obtain a deeper insight onto the mechanism of glauconites evolution. [ABSTRACT FROM AUTHOR]

Sheep milk is considered unstable to UHT processing, but the instability mechanism has not been investigated. This study assessed the effect of UHT treatment (140°C/5 s) and milk pH values from 6.6 to 7.0 on the physical properties of sheep skim milk (SSM), including heat coagulation time, particle size, sedimentation, ionic calcium level, and changes in protein composition. Significant amounts of sediment were found in UHT-treated SSM at the natural pH (∼6.6) and pH 7.0, whereas lower amounts of sediment were observed at pH values of 6.7 to 6.9. The proteins in the sediment were mainly κ-casein (CN)–depleted casein micelles with low levels of whey proteins regardless of the pH. Both the pH and the ionic calcium level of the SSM at all pH values decreased after UHT treatment. The dissociation levels of κ-, β-, and α S2 -CN increased with increasing pH of the SSM before and after heating. The protein content, ionic calcium level, and dissociation level of κ-CN were higher in the SSM than values reported previously in cow skim milk. These differences may contribute to the high amounts of sediment in the UHT-treated SSM at natural pH (∼6.6). Significantly higher levels of κ-, β-, and α S2 -CN were detected in the serum phase after heating the SSM at pH 7.0, suggesting that less κ-CN was attached to the casein micelles and that more internal structures of the casein micelles may have been exposed during heating. This could, in turn, have destabilized the casein micelles, resulting in the formation of protein aggregates and high amounts of sediment after UHT treatment of the SSM at pH 7.0. [ABSTRACT FROM AUTHOR]

Natural Trap Cave, located in the Big Horn Mountains of north-central Wyoming, has a history of trapping and preserving a range of North American fauna that plummeted into the deep vertical entrance. These animal remains were buried and preserved within sediments of the main chamber and, in turn, have helped elucidate the procession of faunal dynamics during the latest glacial cycle. The cave location, south of the Laurentide and Cordilleran Ice Sheets, and proximal to Yellowstone, is at an ideal geographical juncture to provide insights to ecological changes in North America. The sediments that the animals are buried in inform us about transport and deposition both inside and outside of the cave that relate to catchment dynamics. We report on a series of optically stimulated luminescence (OSL) ages derived from samples obtained within the cave during excavation work in 2014 and in 2018. We also examine chronology produced by argon, tephrochronology, fission track, and luminescence techniques that have been used for understanding the infilling of the cave. The cave sediment ages and in situ measured gamma spectroscopy as measured in this study helped resolve an improved chronological age model when combined with previous data. The suite of OSL ages is interpreted through the stratigraphic relationships (and vertebrates contained within) which requires the use of an adequate age model; we use either the central age model or minimum age model where appropriate and with justification. Lowest sediments are dated to ∼150 ka with a hiatus at ∼130 to 52 ka. Above this, sediment deposition and entrainment of paleontological materials are representative of Pleistocene and early Holocene times, between 37 ± 6 ka and 7.6 ± 0.5 ka. The stratigraphic architecture suggests that deposition of materials into the cave is episodic and rapid, followed by quiescent periods where hydrologic scour, heavy overland flow, or possibly a cryo-hydrologic process may have altered unit relationships. Thus, the complementary geochronometers and the characteristics of quartz versus feldspar luminescence signals improve temporal interpretations of these complex deposits. This adapted understanding of mixing also sets the stage for future work with the aim to improve our understanding of ages and sources for ash units within these cave deposits. The three ash units recognized in the cave may represent an in-situ reworking of the same ash or may be representative of previously undocumented eruptions from the Yellowstone Caldera. [ABSTRACT FROM AUTHOR]

Particles sedimentation in porous media is ubiquitous in natural and industrial fields. In this work, the immersed boundary method (IBM) and the lattice Boltzmann flux solver (LBFS) were combined to study the particles sedimentation in porous media for the first time. The hybrid method (IB-LBFS) preserves the advantages of the IBM in treating the solid-fluid boundaries and the LBFS in solving the fluid flow. The effects of porous media arrangement, particle-fluid density ratio, specific surface area, and particle diameter on the behaviors of the settling particles were discussed systematically. The results show that compared with the staggered array porous media, the in-line array porous media are beneficial for particles transport because of the low tortuosity. It is easier for the particles with high density to descend among obstacles due to a higher inertia. The averaged longitudinal coordinate of particles decreases rapidly for higher density ratio, whereas decreases slowly for lower density ratio. For porous media with identical porosity, the channel in porous media with large specific surface area is narrow, leading to the increase in gas-solid interaction and the decrease in particle flow velocity. In addition, for particles with the same total mass, the small particles are easier to descend than the large particles owing to the low collision probability between particles and porous media. The present work not only demonstrates the capacity of the IB-LBFS to deal with complicated fluid-solid interaction problems, but also sheds light on the mechanism of particles sedimentation in porous media. • The immersed boundary-lattice Boltzmann flux solver is firstly employed to investigate particles flow in porous media. • The in-line array porous media is more conducive for particles sedimentation than staggered array. • The porous media with large specific surface area reduce the particles flow velocities. • The smaller particles are easier to descend in porous media than the large particles. [ABSTRACT FROM AUTHOR]

The widespread Early Holocene sea-level rise observed along the global coastal realms reinvigorated the need to decipher sea-level variability on a local and regional scale, yet limited attempts were made on simultaneously addressing sea-level and climate variability. The southwest coast of India is endowed with several geomorphic features providing cues on the paleosea-level and climate variability engrossed with its sedimentary sequence in the lowlands. In view of this, the present study aims to decipher the Holocene sea-level and climate variability based on geochemical and palynological proxies supported by 10 AMS radiocarbon ages on a 32 m long sediment core (L7) raised from Upper Kuttanad Kole wetlands (Kuttoor), Kerala, Southwest India. The study demonstrated high sea-level along with warm and wet climate due to Indian summer monsoon (ISM) intensification during 9.69–7.56 ka corroborating with the Holocene Climate Optimum (HCO). However, a break in the sediment deposition is observed between 7.56 and 3.51 ka, the reason for which is yet to be fully understood. During 3.51–2.55 ka, the gradual weakening of ISM has been invoked with an intermittent monsoon spell during 3.20–3.40 ka. After 2.55 ka the sediment core records occurrence of coarser clastics indicating sediment deposition by the migrating distributary channel of the Pamba-Manimala rivers. The high sea level during HCO attests that the core location plausibly represented the southward extension of the Vembanad lagoon which transformed into part of the terrestrial system due to the gradual sea regression during the mid-late Holocene period followed by deposition of alluvial sediments from the hinterland rivers. [ABSTRACT FROM AUTHOR]

A three-dimensional coupled hydrodynamic and morphodynamic numerical model was developed to analyze sediment dynamics in the Rance estuary, in response to the tidal power station (TPS) built near the mouth in the 1960s. The Rance estuary is a relatively small low-discharge steep-sided ria , located along the Brittany coast in northern France, with a maximum spring tidal range of 13.5m. Taking advantage of this significant tidal regime, the first and currently the second largest operational tidal power station in the world was built at the estuary's mouth, with peak output capacity of 240MW. After calibration and validation of the model for present-day conditions, suspended sediment concentration (SSC) and bed level evolution were evaluated at tidal and fortnightly scales for different scenarios, with and without TPS. Peak SSC are reached during spring tides and specifically during the estuary's infilling (flood) stage where both turbines and sluice gates are open. Unbalanced with sediment transport during ebb, sediments are accumulated in the main channel of the upper estuary. Under natural tidal forcing (i.e., without TPS), simulations show that an estuarine turbidity maximum forms in the upper estuary, and sediment deposition is significant. However, sedimentation rates are two times lower than those observed in the presence of the TPS. A possible alternative for reducing sediment accumulation in the upper estuary would be the opening of sluice gates simultaneously with the turbines during falling tide, to enhance ebb currents that would allow particles transport towards the estuary's downstream. [ABSTRACT FROM AUTHOR]

The sub-micrometer sized TiO 2 particles (100–200 nm) were synthesized by a sol-gel and subsequent thermal annealing. The particle size, surface area, pore structure, and crystallinity were varied upon the annealing temperatures (450, 550, 650 °C). The photocatalytic activities of three TiO 2 particles annealed at various temperatures (450-, 550-, and 650-TiO 2) were examined by performing photocatalytic depollution of three organic model pollutants (methylene blue, methyl orange, and phenol) from aqueous solutions under the UV light irradiation. Among three samples, 550-TiO 2 (~200 nm) exhibited the highest photocatalytic activity towards the removals of all three model pollutants. Photocatalytic activity of the 550-TiO 2 was compared with a commercial TiO 2 (P25, Evonik) at various conditions of loading amounts of particles dispersed in MB solution. Light scattering by dispersed particles at high sample loading conditions was less pronounced in the case of 550-TiO 2. Therefore, the sub-micro 550-TiO 2 particles can exhibit comparable activity to P25 at high sample loading conditions (2–4 g/L). In addition, the bigger size of 550-TiO 2 made it possible to separate them via a simple sedimentation process, showing a potential of sub-micro TiO 2 particles as an efficient photocatalysts for water depollution. [Display omitted] [ABSTRACT FROM AUTHOR]

Sedimentation in front of a dam is the main obstacle against reservoir sustainability. Due to the limited availability of suitable new dam sites, the ramifications of inefficient sediment management are associated with socio-economic concerns and environmental issues. Most of the existing sediment management techniques are unfavorable for arid and semi-arid regions due to their impacts on available water storage and power generation. Therefore, pressure flushing is an economical desilting method as it releases little water through the bottom outlet. However, one of the main disadvantages of pressurized flushing is limited sediment removal near the bottom outlet. In this paper, the impacts of a dendritic, bottomless, and extended (DBE) structure were investigated to develop the scour cone to a broader area. Several experiments were carried out with four different diameters (125, 160, 200, and 250 mm), four different lengths (30, 50, 80, and 110 cm), and three discharge rates (12.5, 15, and 18 L/s), to identify the dimensions of the extended structure with the most efficient operation. The results indicated that the DBE structure with a length dimensionless index of L DBE / D o = 10 , a diameter dimensionless index of D DBE / D o = 1.14 , and an outflow discharge dimensionless index of Fr o = 1.82 , yielded a 36.55-fold increase in the sediment flushing cone dimensions and sediment removal efficiency compared to a reference test. Finally, a dimensionless equation is presented for calculating the sediment flushing cone dimensions, according to a statistical analysis of the results. Two diagrams are provided to illustrate the interrelationship between the distance limits of scour, length, and diameter of the structure and outlet discharges. [ABSTRACT FROM AUTHOR]

Measurements of fog microphysics were conducted during the winter season of 2021 ‐2022 at the Barakah Nuclear Power Plant (BNPP), located in the Western coastal region of the United Arab Emirates. Twelve fog events were observed during this period. The primary objective of this study is to detail the microphysical characteristics of these events and refine current visibility parameterization schemes based on in-situ measurements of fog microphysical properties. All observed fog events are found to share a common feature of a bimodal distribution in droplet number concentration (N d), with modes at 4.5 μm and 23.2 μm. Despite the high proportion of smaller fog droplets associated with the fine mode, the greatest contribution to the liquid water content (LWC) comes essentially from medium to large droplets between 10 and 35 μm. The recalibration of existing visibility parameterization schemes revealed that the increase in horizontal visibility with increasing FI (fog index) tends to be more gradual for the studied cases compared to standard visibility parameterization schemes. Additionally, the fog droplet sedimentation velocity, estimated to be at a maximum of 1.85 cm s−1, occurs predominantly in the LWC range of 100–200 mg m−3, corresponding to a median volume diameter 24.8 μm. Our findings shed new light on the complexity of fog microphysics and its impact on visibility, underscoring their importance in refining weather models for accurate fog forecasting. • Observed consistent bimodal size distribution of fog droplets across 12 fog events, with a dominance of smaller droplets. • Smaller droplets (1-10 μm) formed initially and contributed majorly to Liquid Water Content (LWC). • Larger droplets (10-50 μm) developed later, contributing substantially to total condensed water. • Fog droplets sedimentation velocity can reach up to 1.85 cm s-1, correlated to a median volume diameter of 24.8 µm. [ABSTRACT FROM AUTHOR]

The Nure and Trebbia catchments were affected by an extreme flood event on 13-14th September 2015. This study investigates the morphological responses to the flood of the Nure and Trebbia rivers and 18 tributaries with the aims to: i) quantify channel changes in width and pattern; (ii) identify the morphological and hydrological factors which might have driven channel response; (iii) quantify channel changes which have occurred after the flood event. Channel changes were characterized by field surveys and geomorphological analysis of multi-temporal orthophotos acquired before (2011), immediately after the flood (2015) and in 2020. In the tributaries, reach-scale channel widths after the flood reached up to 15 times their pre-flood values, whereas in the main channels the post/pre-flood width ratio attained a maximum value of 4. Augmented channel width in the main rivers was mostly associated with banks and islands erosion, whereas in the tributaries it was also due to deposition of coarse sediments onto the former floodplains. Islands were swept away in the main channels while both island erosion and formation occurred in the tributaries. In terms of channel pattern, pre-flood single-thread reaches displayed mainly multi-thread morphologies after the flood, mostly in response to a sudden input of coarse sediment supply. In the 5 yr following the flood, channels slightly narrowed but still remained wider than in 2011. The narrower reaches before the flood resulted to be the most sensitive to changes even some years after the flood. Statistical analyses between the channel width changes and a series of variables showed significant positive correlations with confinement index, channel slope, and the local storm rainfall depth. This study confirms how channel widening during large floods – usually neglected in flood hazard mapping and river basin management – is a very important process which must be considered in flood hazard assessment in mountain rivers. [Display omitted] • Flood-induced channel widening greatly differed within the study channels • Multi-thread patterns increased due to the flood in partly confined and unconfined reaches • Local rainfall intensity played a key role in the spatial distribution of channel changes • Narrower reaches were the most sensitive to changes 5 years after the flood [ABSTRACT FROM AUTHOR]

The upstream part of the karst estuary of the Krka River (Prokljan Lake) on the Eastern Adriatic Coast was studied by combining high-resolution seismic data, analyses on sediment cores, and radiocarbon dating to reconstruct the late Quaternary stratigraphy of the estuary. The sedimentary infill consists of up to 20 m of freshwater and estuarine deposits divided into four seismostratigraphic units corresponding to several stages of development since the last glacial period. The lowstand stage is assumed to correspond to fluvial incision and sediment bypass associated with glacial periods. The postglacial transgressive stage is marked by the growth of calcareous tufa barriers and fluvio-lacustrine deposition. The onset of marine influence in the estuary (Prokljan Lake) was recorded at the beginning of the Holocene (>10,500 cal y BP) with the deposition of brackish sediments with a strong freshwater influence. Calcareous tufa barriers prevented direct rapid flooding of Prokljan Lake in the period from >10,500 cal y to ∼7200 cal y BP. Finally, the transgressive brackish deposition changed to estuarine/marine highstand deposition in a salt-wedge estuary during the late Holocene (∼4000–3000 cal y BP). The late Quaternary deposition in this unique karst setting showed dramatic changes. It was primarily influenced by rapid sea-level rise, climate changes, estuarine geomorphology and relatively low sediment supply. • Late Quaternary palaeoenvironmental evolution of a karst Krka River estuary was analysed. • Sea-level, climate changes and tufa barrier deposition controlled the sedimentation. • The flooding of Prokljan Lake started at the begginning of the Holocene. • Tufa barriers had an important role in stepwise flooding of the lake. • Present estuarine conditions developed in the late Holocene. [ABSTRACT FROM AUTHOR]

Abyssal sedimentary dynamic processes are crucial to be understanding the transport and distribution of material (sediment, carbon, plastics, etc.) and the formation of deep-sea bedforms. Accurately characterizing such complicated processes requires a multi-faceted approaches (e.g. numercial models, physical experiments, field observation), among which in-situ field data gathering has been the most challenging. In this study, we collected data from four bottom moorings deployed along the Manila Trench in the northeast South China Sea to investigate the sediment transport processes at the trench bottom. The events with high turbidity, including strong and fast gravity flow and weaker turbidity currents with speed similar to tidal currents, transport sediment down-trench. Sediment particles in the northern part of the trench were generally found to move northward (i.e. up the trench) with seasonal variations primarily influenced by the asymmetrical subtidal currents. During the intensification of northbound subtidal current, the benthic nepheloid layers in Gaoping Canyon, which feeds into the trench, might be transported to the north of trench. Furthermore, a weaker turbidity oscillation at S2 tidal frequencies was observed before turbidity current occurred, increasing sediment transport to the deep. It was hypothesized that multiple small turbidity currents may have been triggered by an earthquake, despite not reaching the mooring S2, with the fine sediment being transported downstream by abyssal tidal currents. • First study to quantify the sediment flux in Manila Trench based on the long-term field measurements is presented. • The directions of mean currents and net sediment fluxes in the northern part of Manila Trench are up trench. • The estimated volume of up-trench sediment transport during the nearly one-year non-turbidity-current conditions was of the same order of magnitude as the down-trench volume by two turbidity currents. [ABSTRACT FROM AUTHOR]

The Gulf of Mexico (GoM) is a unique ecosystem due to its physical characteristics, being influenced by the Mississippi River in the north and the Loop Current from the south, resulting in a gradient of organic to carbonate sediment composition from north to south. The continental slope of the northern and southwestern portions of the GoM are generally well studied; however, less is known about the southeastern GoM along the slope of Cuba. To fill this knowledge gap, sediment cores were collected in 2017 at nine stations (974–1580 m depth) to determine abiotic controls on the deep-sea benthic macrofauna community. Oceanographic data indicated a stratified water column typical of an oligotrophic ocean and no evidence of hypoxia. Sediment texture and composition indicated a west-east gradient likely determined by downslope transport of terrigenous material in the eastern part with a high proportion of carbonate in the west. Heavy metals (Cu, Hg, Pb, and Zn) at concentrations known to cause adverse benthic effects were present in the east near the city of Havana, with the macrofauna community showing characteristics indicative of environmental stress. Overall, this region supported a diverse community of macrofauna families of low abundance, typically only 1–2 animals, and high variability among replicates within stations. Rarefaction curves revealed higher biodiversity per number of individuals in the samples from Cuba compared to those from the nGoM at similar depths, though more samples would be needed to better reveal the true diversity. The major factors influencing macrofauna communities in the continental slope off northwestern Cuba are most likely the lack of organic-rich sediment and low sediment deposition rates, both of which can be attributed to the strong currents and lack of major terrigenous input, along with the regular natural disturbances which prevents domination. • Along the Cuban slope, there was a total of 275 macrofauna collected from 65 families and 9 phyla in 25 cores. • Evidence of toxic levels of heavy metals and adverse community impacts were observed from the station offshore of Havana. • Southeast GoM has low abundance, but higher diversity and evenness compared to northern GoM samples from comparable depths. • Highly heterogenous habitat along Cuban slope resulting in large variation in macrofauna communities. [ABSTRACT FROM AUTHOR]

• Reconstructed four mouth bars' (MB) development history of the West Pearl River. • Hydrodynamic conditions in Pearl Delta allow MB to form from 16 m water depth. • Natural vertical MB growth duration varies between 2800 and 2000 years. • Duration is inversely related to natural depositional rate from 2.7 to 5.7 mm/a. • Sediment supply and antecedent landscape are controlling factors. River mouth bars' formation is a key process of the delta development and river bifurcation, but details of the long-term developmental history of mouth bars and their role in the delta evolution are substantially less well documented. To characterize deltaic mouth bars' development, this study investigated the Sixianjiao, Jun'an, Da'aosha and Denglongsha mouth bars formed successively along the main course of the West Pearl River. The detailed lithological analyses of sediment cores indicate that the mouth bar sediment is characterized by its sandy nature with mud laminations or lenses and poorly preserved foraminifera. The onset of mouth bar sedimentation is affected by water depth. The Sixianjiao and Jun'an mouth bars initiated at shallower water depth (8.0 m and 11.0 m, respectively) due to the restrictions of higher basement landforms. In an area where water is deeper, the mouth bar development would begin only with the site being elevated up to about 16.0 m water depth, such as a case in Da'aosha. The duration between their onset and end of vertical growth varies between 2000 and 2800 years, which is inversely related to their sedimentation rates between 2.7 and 5.7 mm/a, indicating the importance of sediment supply. In addition, the locations of the four mouth bars were to some extent determined by the antecedent landscapes. Finally, the ages of these four mouth bars show a chronological order from land to sea, reflecting seaward delta progradation, contrary to previous morpho-dynamical numerical model's predictions. Our reconstruction of the West Pearl River mouth bars' developmental history provides a new insight into the geomorphological evolution of the Pearl River delta, a special delta developed within a complex estuarine bay. [ABSTRACT FROM AUTHOR]

The natural stratigraphic distribution is uncertain due to the geological tectonic movements and sedimentation. It is a challenge for traditional deterministic models to capture geological uncertainty. The objective of this study is to develop an improved three-dimensional coupled Markov chain (ICMC3D) model based on limited boreholes. The proposed method enhances the traditional three-dimensional coupled Markov chain model by modifying the transition probability equation for predicting unknown elements. The dip data is added to estimate the transition probability matrix with the borehole information. On this basis, a back analysis method is proposed for estimating the horizontal transition probability matrics. The method makes the predicted results more suitable for the possible stratigraphic distribution. The accuracy of the proposed method is verified through some applications. In this paper, an improved three-dimensional coupled Markov chain model and transition probability matrix estimation method are illustrated by the borehole data collected from a tunnel project in Qingdao. The results show that the presented method can reflect the asymmetry, continuity and anisotropy of the three-dimensional stratum. The exceedance probability is proposed to predict the fault zone development range in order to reduce the geological uncertainty. • A modification is made to the traditional coupled Markov chain model in 3D. • Propose the method for estimating the 3D horizontal transition probability matrix. • Propose the method to predict the fault zones development range based on exceedance probability. [ABSTRACT FROM AUTHOR]

Wetlands produce key ecosystem services to mitigate the impacts of peak flows caused by pluvial or fluvial floods or storm surges. Sediment floods were characterized by a peak flow flowing over a simulated wetland, populated with two natural species. Floods have been drawn as flows of height H, into waters of height h, where H > h. Peak flow along the flume passed through: peak flow adjustment; peak flow; drag-dominated peak flow; and gravity current regimes. For high inundation wetland levels, settling rates of coarse and fine sediment were similar during the peak flow regime. At larger distances, sedimentation decreased monotonically, with higher sedimentation of fine particles. For low inundation levels, the sedimentation rate during the drag-dominated peak flow regime was higher for coarse particles. Vegetation decreased the inundation level needed for enhancing sedimentation. Our study then adds practical knowledge at considering that the synergies between the vegetation and the inundation level may enhance wetland services such as the mitigation of pluvial, fluvial or coastal floodings. [Display omitted] • Aquatic emergent vegetation exerts drag on peak flows in inundated wetland systems. • High-inundated wetlands produce flow resistance against peak flows, enhancing sedimentation close to the source. • In low-inundated wetlands, inertia dominates transporting sediment far from the source. [ABSTRACT FROM AUTHOR]

Estimating heterogeneity in carbonate rocks is the most important parameter in identifying reservoir and non-reservoir areas. Diagenetic and sedimentary processes directly control reservoir heterogeneity. In this regard, the high hydrocarbon production rate and the reduction of the complexity of the carbonate reservoirs require the evaluation of a new architecture of the reservoir, in which the simultaneous impact of the diagenetic-sedimentary processes on the petrophysical logs is investigated. The current study studies the Oligocene-Miocene Asmari Formation Iran's giant carbonate reservoir. Based on petrographic studies, sedimentary facies, depositional environment and diagenetic processes were characterized. Formation evaluation was conducted to determine lithology, water saturation, fluid volume, and effective porosity. The estimated porosity from the evaluation of the conventional logs (full suite) was compared with the results of estimating the porosity from the NMR T2 distribution curve and the porosity histogram of the image logs. Lorenz's coefficient of heterogeneity was used to understand the heterogeneity of the reservoir. Diagenetic-sedimentary processes and petrophysical logs were used to investigate the pore type and their distribution. The results of petrographic studies, NMR T2 distribution curve, and porosity histogram show that the diagenetic-sedimentary process is the most important factor enhancing the reservoir heterogeneity. Diagenetic and sedimentary processes were traced by evaluating NMR and Image logs. Based on the results, the porosity distribution using the T2 curve and Image show a good agreement. Diagenetic processes mainly dissolution and dolomitization increased the heterogeneity of the main production zones (zones 3 and 4) of the Asmari reservoir that was confirmed using NMR and Image logs. • An integrated sedimentological/advanced petrophysical analysis for heterogeneity analysis. • Diagenetic and sedimentary processes directly control reservoir heterogeneity. • Diagenetic processes traced by evaluating NMR and Image logs. • Porosity distribution using the T2 curve and Image show a good agreement. • Dissolution and dolomitization increased the heterogeneity of the main production zones. [ABSTRACT FROM AUTHOR]

The study of sedimentary organic matter (SOM) is essential for understanding paleoenvironmental conditions and depositional settings of geological formations. This paper explores the Devonian strata of the Paraná Basin, utilizing SOM analysis to reconstruct paleoenvironments and identify global events. The Devonian period is notable for significant geological and biological changes, including mass extinctions and extensive organic-rich sediment deposition. By examining the composition, distribution, and diagenesis of SOM in this region, we aim to elucidate the paleoenvironmental dynamics and depositional history. The Devonian outcrops in the state of Mato Grosso do Sul, Brazil rocks reveal distinct depositional characteristics, when compared to those found on the eastern border of the basin. The palynofacies analysis was conducted on 59 samples from four outcrops (MS-26, MS-29, MS-30 and MS-70), which age spans from Pragian to Givetian. The main groups and subgroups of the SOM were identified: amorphous organic matter (AOM) ("amorphous organic matter" and pseudoamorphous), phytoclasts (opaques, non-opaque-non biostructured, cuticles, membranes and Spongiophyton) and palynomorphs (spores, freshwater algae, scolecodonts, chitinozoan and acritarchs). The SOM was grouped into three palynofacies associations: opaques, land-derived and marine+AOM. In the Pragian—Emsian interval (MS-26, MS-29 and MS-30), a prevalent occurrence of phytoclasts and marine microphytoplankton is noted, with their distribution exhibiting distinct alternations in each section suggesting a deposition in the marine environment ranging from onshore to offshore. In the Givetian (MS-70 outcrop), we detected a progressive increase and diversification of marine elements (e.g., acritarchs), indicating a transgressive phase probably related with the Kačák event. • Comprehension of the Devonian period within the Paraná Basin, situated in the southwestern part of Gondwana. • Paleoenvironmental reconstruction from Pragian to Givetian in SW Gondwana • Palynofacies [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive analysis of sedimentary successions and paleoenvironmental indicators in two wells, Rh3 and Rh46, located in NE Jordan, within the context of the Ordovician-Silurian boundary transition. By integrating spectral analysis, cyclostratigraphy and sedimentary architecture, significant shifts and cyclical patterns are identified, shedding light on paleoenvironmental changes and orbital forcing dynamics. The study reveals distinct lithological and geochemical signatures at the Risha/Mudawwara (Hirnantian/Rhuddanian) boundary, indicative of major shifts in depositional environments. Analysis of Milankovitch cycles suggests orbital forcing as a driver of sedimentary cyclicity, with implications for understanding climatic variations during the Ordovician-Silurian transition. Spectral analysis revealed significant cycles with different periodicities. Testing the sediment accumulation rates (SAR) revealed an optimum SAR at 5.9 and 4.6 cm/kyr in Rh3 and Rh46 wells, respectively. A new refined astronomical time scale (ATS) is created based on the 100 kyr eccentricity cycle. The new ATS assigns the Risha Formation to the Hirnantian age and revealed a probable time gap at the base of Risha Formation of about 0.3 myr in Rh46 well; deposition of the Risha Formation commenced at 444.88 myr and 444.58 myr in Rh3 and Rh46 wells, respectively, with sedimentation continuing up to the Ordovician/Silurian boundary at 443.07 myr. The Ordovician/Silurian transition experienced shortening in the obliquity and precession cycles. The tuned data show that the 41, 36 and 31 kyr obliquity cycles, in addition the 21, 19 and 16 kyr precession cycles, were recognised. Furthermore, 740, 425, 250, 147 and 100 kyr eccentricity cycles were also recognised. Notably, the study identifies the glacial/fluvioglacial Risha Formation is bounded by g4-g3 eccentricity nodes coinciding with Hirnantian stage boundaries that correspond to significant geological events, such as the Late Ordovician Mass Extinction and the Hirnantian glaciation events. The g4-g3 eccentricity cycle is estimated to be 1.8 myr. Surprisingly, the lower Silurian OAE coincided with the g4-g3 eccentricity node at the Ordovician/Silurian transition. Additionally, the application of DYNOT modelling has elucidated sea-level fluctuations and their relationship with sedimentary sequences, highlighting the role of tectonic and climatic factors in shaping the sedimentary architecture. Furthermore, the investigation of Th/U and Th/K ratios provides insights into marine and terrestrial depositional settings. • Sedimentary Successions Analysis in NE Jordan's Rh3 and Rh46 Wells. • The Ordovician-Silurian boundary transition characterised by significant shifts and cyclical patterns. • Integration of spectral analysis, cyclostratigraphy, and sedimentary architecture..• Revelation of distinct lithological and geochemical signatures at Risha/Mudawwara boundary. • Milankovitch cycle analysis suggests orbital forcing as sedimentary cyclicity driver. [ABSTRACT FROM AUTHOR]

• Unveils how orbital signals are preserved in sedimentary strata. • Highlights the 405-kyr cycle's reliability in ATS. • Demonstrates the impact of sedimentation rates on ATS resolution. Orbital forcing, a primary climatic driver, imprints discernible signatures in sedimentary strata that are instrumental for elucidating climatic change mechanisms and establishing high-resolution astronomical time scales (ATS). Our research dives into sedimentology and cyclostratigraphy, tackling the longstanding enigma of how orbital signals survive in dynamic environments where sediment deposition occurs at highly variable rates. Utilizing a stochastic sedimentation model, we simulate stratigraphic records containing orbital rhythms, representative of a range of depositional settings. We show that the 405-kyr eccentricity cycle is often the most reliably preserved, and sometimes even the sole trustworthy metronome in devising ATS among various tuning strategies. This holds particularly true in environments with high energy and unsteady sedimentation, such as fluvial or deltaic settings. In contrast, environments with lower sedimentation rate variability and higher overall sedimentation rates allow for the use of shorter-period orbital parameters in astronomical tuning, thereby enhancing the temporal resolution of ATS. This study has implications not only for decoding past climate forces but also for refining the precision of ATS, contributing significantly to our understanding of Earth's geological history. [ABSTRACT FROM AUTHOR]

• Ion exchange, volcanic ash dissolution, and authigenic clay formation concurrently control sedimentary Li budget. • Rates of volcanic ash alteration vary substantially among sites with different sedimentation rates. • The dominance of volcanic ash dissolution or clay authigenesis on Li budget is dependent on rate the ash deposition. • Rapid depositional system with sufficient volcanic ash supply can act as a source of isotopically light Li. • This previously unrecognized Li source from ash alteration may be crucial in resolving marine Li cycle. Volcanic ash alteration is deemed a crucial diagenetic process that can impact element budgets in the ocean. In this study, we aim to evaluate the role of volcanic ash alteration in controlling sedimentary lithium (Li) cycling through Li isotope analyses of pore fluids and sequentially leached fractions of bulk sediments (i.e., exchangeable Li, carbonate-bound Li, and silicate-bound Li) of three sites drilled along a transect from the incoming to the upper plates of the Hikurangi margin, New Zealand, during IODP Expedition 375. The downcore trends of Li concentration and isotopes in the Quaternary hemipelagic sediments of the three study sites reflect multiple concurrent diagenetic processes, including Li desorption via ion exchange with ammonium, volcanic ash dissolution, and authigenic clay formation. Reaction-transport modeling results yield higher rates of Li release by ion exchange and volcanic ash dissolution than those of Li consumption by authigenic clay formation at both Sites U1518 and U1520, leading to a net increase of Li concentration up to 252 μM and lower δ 7Li (10.4–23.5 ‰) than seawater. At Site U1519, authigenic clay formation exerts a larger role in regulating sedimentary Li budget than ion exchange and ash dissolution. Notably, the drastic increase in Li concentrations and the decrease in δ 7Li values at the boundary of Units III/IV of Site U1520 are attributed to the extensive autochthonous volcanic ash alteration, rather than Li transport by fluid flow. Similar Li geochemical profiles have also been observed in other ash-bearing sediments worldwide, e.g., Site 918 drilled in the Irminger Basin, southeast Greenland, Site 1040 in the Costa Rica subduction zone, and Site 808 in the Nankai Trough. Additional reaction-transport simulations of Li data show that volcanic ash dissolution rates outcompete clay authigenesis rates at sites that have experienced rapid sediment deposition (0.05–0.14 cm yr−1); in contrast, clay authigenesis dominated the pore-fluid Li budget at Site 919 where a low sedimentation rate (7.1 × 10–3 cm yr−1) was estimated. Based on these observations, we surmise that the rapid depositional system with sufficient volcanic ash supply can act as a source of isotopically light Li, in contrast to the general perception that volcanic ash alteration represents a major sink for oceanic Li. This previously unrecognized Li source may be important in the marine Li cycle. [ABSTRACT FROM AUTHOR]

• The four-way coupling CFD-DEM method is employed to calculate sedimentation shape of particles. • Only a single numerical code, Fluent, is utilized to perform the CFD-DEM coupling calculations. • Three phases, which are water, air, and particles are incorporated in multiphase flow analysis. Numerical calculations of the bed shape formed by particles descending into a water-filled pool have been conducted using the CFD-DEM coupling Eulerian-Lagrangian method, implemented within Fluent code. The mixture model has been employed to simulate the multiphase flows involving water–air fluids. The simulations account not only for the interactions between the fluids and particles but also for collisions, sliding friction and rolling friction between particles (or particles and the wall). The numerical simulations have been performed to investigate the sedimentation shapes for four cases: 4 mm diameter particles (ZrO 2 and Stainless Steel) and 6 mm diameter particles (ZrO 2 and Al 2 O 3). These particles have been released into a water-filled pool with a diameter of 375 mm. The results indicate that the calculated shapes of the porous bed have been obtained with a reasonable level of accuracy. [ABSTRACT FROM AUTHOR]

Unconsolidated regolith from fluvial and hillslope origin occurring along the eastern seaboard of the Northeastern Brazil passive margin has long been overlooked as viable proxy for Quaternary environmental changes, or simply dismissed and interpreted as sediments of older planation cycles, for example, Neogene sediments. This study applies geochemical and geochronological techniques to assess the degree of weathering, sediment provenance and time of residence in the landscape. The results shed light on the upper Quaternary geomorphological history of the Borborema Piedmont, with depositional units spanning the last 50,000 years, as a response to climatic inputs in sync with major Pleistocene events (e.g., Heinrich Event 1, 2, 3 and 5, Last Glacial Maximum) and Holocene events in the Northern Hemisphere (e.g., Holocene Climatic Optimum), and the morphotectonic rearrangement of stream channels base level along reactivated fault-line subordinated to the underlying Proterozoic structural framework. [Display omitted] • OSL data show sedimentation in tropical area is driven by abrupt climate changes. • Sedimentation in the study area dates to at least since the Heinrich 5 Event. • The Piemonte of Borborema Plateau has two main sedimentation phases: ∼25 and ∼9 Ka. • Neotectonic was responsible for the creation of hollows and changes in base level. [ABSTRACT FROM AUTHOR]

Salt marshes, serving as crucial ecosystems and carbon repositories, are currently under threat from climate change and anthropogenic activities. The formation and retreat of marsh-edge cliffs represent a major mechanism of marshland degradation and subsequent release of sequestered organic carbon. The volume of coastal erosion is determined by the product of cliff height and retreat rate; however, the factors governing cliff height remain elusive. In this study, we introduce an idealized process-based model to investigate the initial formation of marsh-edge cliffs and examine how cliff height responds to tidal range, sediment supply, and marsh bed erodibility. The results suggest that cliff height is primarily controlled by the tidal range, showing a strong positive correlation. An increase of 1 m in the tidal range corresponds to a rise of 0.2–0.3 m in cliff height. This is because, in macro-tidal flats, the elevation range suitable for marsh growth is broader, trapping muddy sediments within the marshes, which eventually leads to the formation of taller marsh-edge cliffs. The mud concentration at the open boundary (i.e., sediment supply) has limited impact. Additionally, an increase in marsh bed erodibility can modestly reduce cliff height. This model offers a basis for predicting marsh-edge cliff heights in the face of future environmental changes. Contrary to previous studies suggesting larger tidal ranges support salt marsh sustainability by fostering sediment deposition on the marshes to balance sea level rise, they could, in fact, elevate cliff heights, thus may accelerating erosion and increasing erosion volume. Consequently, the formation and retreat of marsh-edge cliffs demand significant focus for the conservation of meso- and macro-tidal coastal marshes. • Tidal range primarily governs marsh-edge cliff height with a strong correlation. • An increase of 1 m in tidal range raises cliff height by approximately 0.2–0.3 m. • Sediment supply has limited impacts on cliff height. • Higher marsh bed erodibility modestly reduces marsh-edge cliff height. • Marsh-edge cliffs require attention in meso- and macro-tidal marsh conservation. [ABSTRACT FROM AUTHOR]

Seagrass meadows are one of the world's most diverse ecosystems offering habitats for an extensive array of species, as well as serving as protectors of coral reefs and vital carbon sinks. Furthermore, they modify hydrodynamics by diminishing water flow velocities and enhancing sediment deposition, indicating the potential for microplastic accumulation in their sediments. The build-up of microplastics could potentially have ecological impacts threatening to ecosystems, however little is known about microplastic abundance and controlling factors in seagrass sediments. Here we investigated microplastic characteristics and abundances within sediments underlying four seagrass meadow sites on the Turneffe Atoll, Belize. Sediment cores were collected and sub-sampled to include a range of replicate surface sediments (0–4 cm) and depth cores (sediment depths 0–2, 2–5, 5–10, 10–20 and 20–30 cm). These were analysed using 25 μm resolution μFTIR, with spectral maps processed using siMPle software. Microplastics were prevalent across the sites with an abundance range (limit of detection (LOD) blank-corrected) of < LOD to 17137 microplastics kg−1 dw found on the east side of the atoll. However, their abundances varied greatly between the replicate samples. Polyethylene and polypropylene were the most commonly detected polymers overall, although the dominant polymer type varied between sites. There were no differences in the abundance of microplastics between sites, nor could abundance distributions be explained by seagrass cover. However, abundances of microplastics were highest in sediments with lower proportions of fine grained particles (clay, <4 μm) suggesting that hydrodynamics override seagrass effects. Additionally, no patterns were seen between microplastic abundance and depth of sediment. This suggests that microplastic abundance and distribution in seagrass meadows may vary significantly depending on the specific geographical locations within those meadows, and that more complex hydrodynamic factors influence spatial variability at a localised scale. [Display omitted] • Maximum concentration 19342 microplastics kg−1 far exceeds other seagrass studies. • Polymer types were highly variable by location. • Local hydrodynamics influence microplastic deposition and retention within sediment. • Seagrass cover did not influence microplastic concentrations. • There was no trend between sediment depth and microplastic concentration. [ABSTRACT FROM AUTHOR]

A large amount of silver nanoparticles (AgNPs) and short-sized silver nanowires (AgNWs) were produced in the reaction of AgNW synthesis by the polyol method. These impurities immensely affected the practical application of AgNWs dispersion. To promote the electrical property of AgNWs, it is necessary to develop a cost-effective method to separate impurities in AgNWs dispersion. Herein, we developed a new purification strategy called centrifugation-sedimentation separation-centrifugation to purify the ultra-long AgNWs (average length of 98.26 μm and the aspect ratio of 1240) synthesized by an improved polyol method. The yield of sedimentation separation was up to 78.1 % in this strategy. Based on the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the sedimentation mechanism of the ultra-long AgNWs and impurities was systematically investigated. The AgNWs/polyurethane (PU) composite foam prepared by the impregnation method with purified ultra-long AgNWs demonstrated a superior conductivity of 13227 S/m, which was twice than that of the composite foam with unpurified ultra-long AgNWs. The resistance variation of the purified ultra-long AgNWs -5 /PU sensor was only elevating 11 % after 100 cycles of 100 % strain compression at 1 Hz frequency, while the AgNWs -5 /PU sensor prepared from commercial 20 μm AgNWs showed a resistance change of up to 492 %. Our study provides a low-cost, highly selective, and efficient purification strategy for ultra-long AgNWs dispersions, and also demonstrates that ultra-long AgNWs can enhance the sensing stability and durability of AgNWs/PU foam sensors. [Display omitted] • A centrifugation-sedimentation separation-centrifugation novel strategy was developed for purifying ultra-long silver nanowires (AgNWs). • The purification strategy maintains the separation yield of AgNWs at 78.1 % on average. • The AgNWs-5/PU sensor prepared by ultra-long AgNWs has excellent conductivity (13227 S/m), good sensing stability and durability. [ABSTRACT FROM AUTHOR]

The study of manganese (Mn) and iron (Fe) cycling in early diagenetic processes in estuaries is crucial for understanding the functioning of these vital ecosystems and predicting their responses to environmental change. The present study investigates the dynamic interplay of Mn and Fe in early diagenetic processes at highly contrasted hydrosedimentary conditions in the Loire estuary, which is very rare and allows a comprehensive framework to understand diagenetic processes in a very dynamic environment. One campaign took place in the Brillantes intertidal mudflat in March 2015 (PV1), while 3 others took place in a muddy riverbed along the navigation channel off the city of Paimboeuf during a decennial flood in February (RR1–4), under moderate discharge in June (RRK-4) and low in August 2021 (RR2–4). The monitored riverbed station was upstream, under and downstream the maximum turbidity zone, respectively. By combining sequential extraction techniques for Mn and Fe in solid phases and pore-water analysis, the study provides insights into the behaviour of these elements in sedimentary environments and reveals their speciation and association with specific mineral phases and forms during different diagenesis stages. The remobilization of Mn and Fe in the surface sediments of the Brillantes mudflat (PV1) allows iron sulphide formation within the upper 50 cm of the sediment column (above the sulphate penetration depth). The deeper layers show other authigenic phases formation, such as the probable precipitation of vivianite below the sulphate depletion depth and progressive precipitation of carbonate at depth, leading to definitive burial and accumulation. At the muddy riverbed, following the exceptional flood in February 2021 (RR1–4), significant sediment erosion occurred unveiling to the water column old and reduced sediments. Sharp pore-water gradients for dissolved Mn, Fe and sulphate indicated the sudden exposure of the old 7Be-free and anoxic sediment to low-salinity, well‑oxygenated water. Despite its dark colour, this sediment showed no authigenic FeS/FeS 2 phases. Four months later, changes in the estuarine environment (low river discharge) and the presence of a maximum turbidity zone (TMZ) led to a new deposition of a sediment layer (RRK-4) triggering transient diagenetic reactions. The freshly deposited sediment layer developed important recycling of dissolved Mn, Fe and sulphate above the precedent sediment water interface (SWI) generating a double peak, accompanied by consistently low concentrations of solid Mn and Fe phases specially FeS/FeS 2 and Mn bound to FeS/FeS 2 compared to PV1. Six months after the flood event, in August (RR2–4), the discernible attenuation of dissolved Mn and Fe peaks and sulphate concentration, indicated a gradual recovery of characteristic sediment profiles with the well-known redox layer succession. Overall, despite important sulphate reduction within sediments from both the river and its adjacent mudflats, pyritization is not a major process for Mn and Fe burial. The intense hydrodynamics of the mid estuary prevents thermodynamical equilibrium between pore-water chemistry and solid phases not allowing pyrite formation while in the calmer conditions of intertidal mudflats, pyrite accumulates in intermediate depths but carbonates and phosphates seem to be the preferential phases of burial probably related to methane production and phosphate availability. • A sequence of authigenic Fe and Mn mineral formation was observed in the intertidal mudflat. • Hydrodynamic events in the muddy riverbed do not favour major mineral transformations. • Erosion/sedimentation events and ensuing relaxation were evidenced by pore-water data. [ABSTRACT FROM AUTHOR]

• Models for predicting near-bed TKE and deposition below a floating canopy of vegetation were proposed and validated. • Deposition decreased with increasing channel-average velocity and vegetation density or decreasing relative flow depth. • Rigid cylinder arrays can effectively simulate real E. crassipes canopies, and the proposed model was valid for E. crassipes. Floating canopies of vegetation alter the vertical profile of flow velocity within and below canopies, which in turn impacts sediment deposition below canopies. This study explored the impacts of channel-average velocity (U 0), vegetation density (a), and relative flow depth (h g / H , where h g is the height of the free flow region below the floating canopy and H is the entire flow depth) on the longitudinal distributions of near-bed turbulent kinetic energy (TKE) and sediment deposition in a channel with a floating vegetation canopy. Below a floating canopy, sediment deposition was correlated with the near-bed TKE. For the low-density and low-velocity cases, sediment deposition was spatially uniform across the entire channel because the near-bed TKE was lower than the critical value for sediment resuspension. As the vegetation density and channel-average velocity increased, the near-bed TKE increased and surpassed the critical TKE , which caused resuspension and reduced deposition below the canopy relative to the upstream reference. For the same vegetation density and channel-average velocity, a lower relative flow depth (h g / H) produced a higher below-canopy depth-averaged velocity and near-bed TKE , resulting in less deposition below the canopy. A model was proposed for predicting the longitudinal evolution of near-bed TKE based on the predicted flow velocity below the canopy throughout the channel. The longitudinal evolution of deposition below a floating canopy was predicted by combining the predicted near-bed TKE with the deposition probability. The predicted near-bed TKE and deposition matched laboratory measurements. Finally, the proposed model can be used to predict the longitudinal profile of deposition below a real Eichhornia crassipes canopy. [ABSTRACT FROM AUTHOR]

• A novel large-scale hydrological and hydrodynamic coupled model for flow routing. • A new implicit fully coupling algorithm in coupled hydrological-hydrodynamic model. • Complex interactions among river–lake systems can be simulated accurately. • Quantifying the impacts of topographic changes on hydrological regime using limited data. In lowland alluvial river systems consisting of mainstream, distributaries, and floodplain lakes, the flow dynamics are characterized by changing backwater effects and seasonal water storage and release, and the bed morphology is unstable due to frequent sediment deposition and erosion. Hence, models that can accurately and efficiently simulate hydraulic interactions with low topographic data demands are required for such water systems. In this study, we present a coupled flow routing model for the Yangtze River-Dongting Lake system by coupling a 1D hydrodynamic model for the mainstream with hydrological models for distributaries and the lake. A new approach is proposed to generate a set of rating curves to represent the combined impacts of the inflow and outlet stage on the lake storage volume, thereby an innovative hydrological routing method fully considering backwater effects is established. Additionally, an implicit fully coupled algorithm is presented to integrate the hydrodynamic and hydrological models, which demonstrates ideal numerical stability and high computational efficiency. The coupled model is applied to flow routing in the Yangtze-Dongting system, with the Nash-Sutcliffe efficiency coefficients above 0.960, and most of the mean absolute error below 0.4 m (1000 m3/s) for stage (discharge). The model is also used to evaluate the impact of topographic changes during 1998–2016 on the flow process. The results indicate that the mainstream stage has decreased notably, while the reduction of the storage capacity of the lake is not yet remarkable. For the model proposed in this paper, only hydrological data and mainstream topographic data are necessary during model development, calibration, and application. In the context of continuous channel/lake bed adjustment in the middle reach of the Yangtze River Basin, the coupled model provides an effective tool for quantitatively evaluating the hydrological regime and flood process of a river system at a full scale. [ABSTRACT FROM AUTHOR]

Continental rift systems are commonly characterized by volcanism with parental basaltic magmas sourced from the mantle. Erosion of the rift shoulders and sedimentation in the adjacent basins can affect the stress and thermal fields at depth, thereby affecting partial mantle melting. However, the sensitivity of magmatic activity to such surface forcing is elusive. Geological observations from the western Ross Sea, Antarctica, suggest rift onset in the Cretaceous with a transition from wide-rifting to narrow-rifting at the boundary between the Antarctic craton and the Transantarctic Mountains. Miocene climate cooling during rifting in the western Ross Sea, in addition, leads to an abrupt decrease in sedimentation rate, synchronous to the emplacement of the McMurdo Volcanic Group. This represents the largest alkali province worldwide, extending both inland and offshore of Transantarctic Mountains and western Ross Sea, respectively. Here, we use coupled thermo-mechanical and landscape evolution numerical modeling to quantify melt production in slowly stretching rift basins due to changes in erosion/deposition rates. The model combines visco-elasto-plastic deformation of the lithosphere and underlying mantle during extension, partial rock melting, and linear hillslope diffusion of the surface topography. The parametric study covers a range of slow extension rates, crustal thicknesses, mantle potential temperatures and diffusion coefficients. Numerical simulations successfully reproduce the ∼150–200-km-wide extension of western Ross Sea and Miocene-to-present asthenospheric melt production (McMurdo Volcanic Group). Results further show that slow rifts magmatism is highly sensitive to sediment deposition within the basin, which inhibits mantle decompression melting and delays the crustal breakup. Regional climate-driven sedimentation rate changes are thus likely to have affected the syn -rift magmatic history of the western Ross Sea, Antarctica, supporting the relevance of interactions between surface and deep-seated processes across extensional settings. • Low sedimentation rates enhance decompression rock-melting in continental rift basin. • Syn-extensional magmatism and tectonic deformation in ultra-slow rifts are sensitive to surface processes. • Miocene aridification and sediment starvation affect the lithospheric thermal state and the stress field. • Neogene to Quaternary volcanism in western Ross Sea, Antarctica, is affected by global climate cooling. [ABSTRACT FROM AUTHOR]

It is crucial to determine the sequence of deformation and the interaction between shallow and deep structures within the multiple detachment systems to comprehend geological processes fully in fold-and-thrust belts (FTBs). Here, we implement forward modeling to investigate the geometric, kinematic, and syntectonic sedimentary characteristics of shallow and deep structural interactions. We design four combinative patterns of geometric structures, three kinematic sequence scenarios, and two settings with different ratios of the sedimentation rate to the uplift rate to examine the influence of such settings on growth strata geometry. The most effective results of 24 groups of shallow and deep structural interactions were obtained for various combinations of fault-bend fold, detachment fold, and tectonic wedge. This study provides a sequential kinematic image of FTBs, illustrating the interaction of two sets of detachments and demonstrating how different styles of pre- and growth strata can be utilized to identify shallow and deep structure deformation processes. The geometry of pre- and growth strata observed in the models is similar to that observed in natural structures. These forward models facilitate a better understanding of the complex geometry and kinematics of the interaction between shallow and deep fault-related folds. • Interactions in foreland-and-thrust belts (FTBs) may be complex and hard to model. • Forward modeling was used to study their kinematics, geometry, and sedimentology. • 24 groups of shallow and deep structural interaction results were obtained. • Different sedimentation rates result in different forms of structural interaction. • Results demonstrate effective forward modeling of tectonic geometries. [ABSTRACT FROM AUTHOR]

Detrital quartz grains extracted from sebkha sediments in southeastern Tunisia underwent scanning electron microscopy analysis to identify sediment sources and assess the influence of the saline environment on the grains. Core sediments collected from Sebkha el Melah and Sebkha Mhabeul cover the last 5000 and 2000 BP, respectively. The uppermost Unit III, present in both cores, exhibits two distinct facies based on the mechanical microtextures of its quartz grains. The aeolian facies sediments are characterized by quartz grains with rounded outlines, upturned plates, and crescentic percussion marks. In contrast, the fluvial facies sediments are associated with quartz grains featuring subangular outlines, v-shaped percussion cracks, conchoidal fractures. Observations on the quartz grains of the sebkhas suggest multiple transportation and processing events, indicating long-distance transport and rapid deposition rates. The majority of quartz grains appear to originate from the surrounding terrain, reflecting the dynamic geological history of the region. This study delves into the connection between microtexture variations on quartz grain surfaces and specific historical climatic conditions in the sebkhas. By examining geochemical variations along the cores, facies with elevated salt concentrations corresponding to warmer periods reveal extensively weathered quartz grains. This substantial chemical alteration is evident through microtextures such as oriented etch pits, anastomosed dissolution networks and solution crevasses. The profound dissolution has significantly impacted the quartz lattice, resulting in the decomposition of the grains and the formation of "cauliflower" or "spongy" shapes, erasing prior microtextures. Conversely, during less warm periods, quartz dissolution was less severe, thereby preserving microtextures. Sand grain surfaces are notably sensitive to both transport processes and variations in the physicochemical environment. In the hypersaline and confined environments of sebkhas in southeastern Tunisia, potent post-sedimentary processes can obliterate and obscure the original microtextures recorded on grains from previous environments due to highly fluctuating physicochemical conditions. • Quartz grain microtextures have been analyzed to identify sediment sources in Tunisian sebkhas. • Fluvial deposits show angular grains with v-shaped cracks, indicating water transport. • Aeolian deposits show rounded grains with crescentic percussion marks, indicating wind transport. • High salt concentrations recorded during warm periods enhance chemical weathering on quartz grains. • Hypersaline conditions can obscure previous textures on quartz grain surfaces. [ABSTRACT FROM AUTHOR]

The closure of the Paleo-Tethys Ocean and subsequent collisional orogenesis in the early Mesozoic played an important role in the formation of the Qinghai–Tibetan Plateau. However, the final closure of the southernmost Paleo-Tethys branching ocean basin in the Qinghai–Tibetan Plateau—known as Sumdo Paleo-Tethys Ocean—and collision between Central and Southern Lhasa terranes remain controversial. In particular, the tectonic significance of early Mesozoic volcanism and sedimentation in the Lhasa terrane is unknown, but crucial for understanding the final stages of ocean closure. Here, we investigate the depositional ages and provenance of detrital zircon in clastic sedimentary rocks, as well as the petrogenesis of the interbedded andesite from the volcano-sedimentary sequence of the Late Triassic to Early Jurassic Xionglai Formation in the Tangjia-Sumdo area. Detrital zircon dates from the Xionglai Formation define five age peaks at 180–200 Ma, 230–340 Ma, 500–620 Ma, 1000–1240 Ma, and 1600–1800 Ma. Detrital zircon trace elements and Hf isotopic characteristics are interpreted to represent derivation from an accretionary wedge and later magmatism related to oceanic slab break-off as well as a minor component from coeval magmatic rocks in the Nyainrong-Nang area in northern Lhasa terrane. Interbedded andesite has a magnesian andesite signature and yields ages of 192–184 Ma with zircon ε Hf (t) values that range from −3 to +1. We interpret these data as the andesite being sourced from sediment-derived melts that interacted with the overlying mantle wedge in a post-collision extensional setting. Our study suggests that the closure of the Sumdo Paleo-Tethys Ocean and subsequent collision between Central Lhasa and Southern Lhasa terrane may have happened in Late Triassic-Early Jurassic. The final closure of the multi-Paleo-Tethys Ocean and subsequent collision in the Qinghai–Tibetan Plateau may have induced initial subduction of the Meso-/Neo-Tethys Ocean, representing the tectonic transition from collision/post-collision to subduction/accretion in the Qinghai–Tibetan Plateau during the Late Triassic to Early Jurassic. • The Xionglai Formation yields young peak age of ca.195 Ma. • Early Jurassic magnesian andesite was identified from the Xionglai Formation. • The Xionglai Formation was deposited in a post-collision extensional setting. • The Sumdo Paleo-Tethys Ocean likely closed during the Late Triassic-Early Jurassic. [ABSTRACT FROM AUTHOR]

Today, due to the use of pipelines in riverbeds to transport water, petroleum products, gas, etc., which is an unnatural human intervention in riverbeds, the riverbed has suffered from local erosion and there are many risks such as pipe breakage and damage. As a result, it is important and necessary to reduce and control this local scouring. The current study has investigated the effect of placement of rip-rap structure on the reduction of local scouring caused by a semi-buried pipe along with a protective inclined floor at a 90-degree from a bend using by Flow3D numerical model. The scenarios of this research include 3 different sizes of rip rap elements and 2 rip rap scenarios consisting of 3 non-uniform layers. Comparison of numerical model results with laboratory data showed that this software is capable of simulating this sedimentary model. The simulation results showed that with the increase in the size of the rip-rap element, the amount of scouring and sedimentation after the bottom band decreases. Also, the use of rip-rap with non-uniform layers, in the case where the layers were placed from fine grain to coarse grain, caused a further reduction in local scouring. • Using a 3D numerical model and validating the numerical model with the laboratory model. • Studying the effect of rip-rap on the reduction of scour downstream of the protective inclined apron. • Studying the effect of rip-rap arrangement on the reduction of scour downstream of the protective inclined apron. [ABSTRACT FROM AUTHOR]

Sediment deposition in coastal wetlands is key to maintaining marsh elevation during periods of sea level rise. Deposition occurs naturally during storms to increase marsh elevation or when dredged sediments are intentionally introduced during restoration to build elevation capital. The deposition of sediments containing iron sulfide compounds (FeS and FeS 2) under natural or managed scenarios alters biogeochemical cycles, including the potential to induce dramatic declines in soil pH under prolonged oxidizing conditions. This 20-week mesocosm study investigated FeS and FeS 2 dynamics under continuously flooded, tidal, and drought treatments following a simulated natural or restoration deposition event by placing hyposulfidic sediment onto the marsh soil surface. The introduced FeS and FeS 2 rapidly oxidized (< 21 days) after sediment deposition across all treatments, followed by declining oxidation reduction potentials, increasing dissolved Fe concentrations, and subsequent FeS and FeS 2 re-precipitation in flooded and tidal treatments. Nominal pH declines occurred in flooded and tidal treatments due to re-precipitation of FeS and FeS 2 minerals. Conversely, pH decreased 1–2 units under simulated drought conditions. Observational and modeling results indicate that S−2 generation limited the rate of FeS and FeS 2 formation following sediment deposition in alignment with previous field studies. Results suggest that the deposition of hyposulfidic sediments during storms and restoration events pose minimal risk of acidification when prolonged saturated conditions are present. However, short term FeS and FeS 2 oxidation and re-precipitation likely occur following both natural (over wash) and managed (restoration) scenarios as the deposited sediments achieve new dynamic biogeochemical equilibria. Coastal resource managers can use these results to ensure restoration projects maximize positive restoration outcomes while minimizing the risk of soil acidification through the informed management of FeS and FeS 2 minerals. • Hyposulfidic sediment deposition induced wetland soil biogeochemical changes, including pH change under simulated drought • Iron sulfide compounds oxidized when deposited, then re-precipitated under saturated conditions • Hyposulfidic sediment deposition poses low acidification risk under saturated conditions • Soil morphology provided a useful proxy measure of sediment Fe & S biogeochemistry • Results inform wetland management following storm driven deposition and deliberate sediment introduction during restoration [ABSTRACT FROM AUTHOR]

Trough mouth fans (TMFs) are major submarine depocentres that form in front of ice streams advancing onto the continental shelf, and they provide extensive records of past glaciations and ice-sheet dynamics. However, early research about TMFs was conducted using primarily 2D seismic data, which limits the insights on the deposit's geometries and internal structures and more recent studies using 3D data have focused on the general depositional history of TMFs. Here, we assess the spatial and temporal changes of the glacio-marine landforms and deposits throughout the last glacial-interglacial cycle (Marine Isotope Stage (MIS) 6 to 1, ∼130 ka to present) recorded in a >550 m thick progradational sequence. We use 3D reflection seismic data with significant vertical resolution (up to 2 m) imaging over 14000 km2 from the uppermost North Sea Fan (NSF) to document the seismic stratigraphy and sedimentary processes, by combining horizon picking and geomorphological analyses. The studied interval comprises five mappable units, four on the slope and one on the shelf, spanning from the modern seabed down to the top of the Tampen Slide (∼130 ka). Five different channel types (here included slide scars), as well as contourite and plumite packages are described based on their seismic facies, morphology, geometry, and stratigraphical position. We propose that contour currents are responsible for sediment delivery after the Tampen Slide deposition during the interglacial period before the onset of the Last Glacial Maximum, when high meltwater influx from the shelf produced turbidites. Sedimentation became debris-flow-dominated towards the end of the period of shelf-edge glaciation. The deglacial interval is characterized by the deposition of plumites on the slope. On the shelf, subglacial tills are deposited during both glacial and deglacial periods. We calculate an average sedimentation rate of <1 m/kyr during the interglacial (MIS 5-3), and around 50–65 m/kyr during the glacial and deglacial periods (MIS2-early MIS1). Thus, we document a change of two orders of magnitude in sedimentation rate during a glacial cycle on the slope of a glaciated margin. • 3D seismic imaging of the Late Pleistocene deposits of the North Sea TMF. • The geological record includes the sediments of a full glacial-interglacial cycle. • Contourites on the slope (interglacial) accumulated with an average rate of 0.7 m/kyr. • Glacial and deglacial periods have much higher sedimentation rates (65 and 50 m/kyr). • Shift from meltwater turbidites to debris flows during the shelf-edge glaciation. [ABSTRACT FROM AUTHOR]