Mud Deposits Research Articles

Holocene paleoenvironmental changes in mud area southwest off Cheju Island, East China Sea: Evidence from benthic foraminiferal assemblages and stable isotope records

A sediment core retrieved from the mud area southwest off Cheju Island (MASCI) was analysed for benthic foraminifera, grain size, and stable isotopes and constrained by AMS14C dating. Holocene paleoenvironmental changes in this broad shallow shelf were investigated, with special focus on the evolution of the MASCI and its related ocean eddy system. The results indicate that the East China Sea shelf has undergone four major environmental evolution stages during the Holocene. Prior to 9.8 cal. Kyr BP, the benthic foraminiferal assemblages were dominated by low salinity, shallow-water species [Ammonia beccarii (Linnaeus), Elphidium advenum (Cushman), and Cribrononion subincertum (Asano)], reflecting a near-coast-deposit environment. A noticeable transition of the benthic foraminifera, from an A. beccarii dominated to Ammonia compressiuscula (Brady) dominated assemblage, taking place at approximately 9.8 cal. Kyr BP together with a contemporaneous increase in δ18O and δ13C, provides evidence that a rapid rise in sea level occurred at this time in the East China Shelf. A gradual increase in δ18O between 9.8 and 6 cal. Kyr BP indicates a steady strengthening influence of open ocean water on the area under study. A sudden increase in the abundance of benthic foraminifera along with a decrease in the coarse fraction imply that an early eddy circulation system was established since almost 6 cal. Kyr BP in the MASCI. This eddy circulation system was quite weak but gradually strengthened between 6 and 3 cal. Kyr BP, possibly due to the intrusion of the Yellow Sea Warm Current (YSWC). A more stable mud deposition period, characterised by a high sedimentation rate of fine-grained sediment and lighter value of δ13C, starting at approximately 3 cal. Kyr BP, indicates that the MASCI was formed mainly during the late Holocene. We believe that the strengthened YSWC since 3 cal. Kyr BP might increase the trap efficiency of the eddy system, thereby accounting for the high sedimentation rate of mud deposits during this period.

Sediment Transport near Ship Shoal for Coastal Restoration in the Louisiana Shelf: A Model Estimate of the Year 2017–2018

Ship Shoal has been a high-priority target sand resource for dredging activities to restore the eroding barrier islands in LA, USA. The Caminada and Raccoon Island pits were dredged on and near Ship Shoal, which resulted in a mixed texture environment with the redistribution of cohesive mud and noncohesive sand. However, there is very limited knowledge about the source and transport process of suspended muddy sediments near Ship Shoal. The objective of this study is to apply the Regional Ocean Modeling System (ROMS) model to quantify the sediment sources and relative contribution of fluvial sediments with the estuary and shelf sediments delivered to Ship Shoal. The model results showed that suspended mud from the Atchafalaya River can transport and bypass Ship Shoal. Only a minimal amount of suspended mud from the Atchafalaya River can be delivered to Ship Shoal in a one-year time scale. Additionally, suspended mud from the inner shelf could be transported cross Ship Shoal and generate a thin mud layer, which is also considered as the primary sediment source infilling the dredge pits near Ship Shoal. Two hurricanes and one tropical storm during the year 2017–2018 changed the direction of the sediment transport flux near Ship Shoal and contributed to the pit infilling (less than 10% for this specific period). Our model also captured that the bottom sediment concentration in the Raccoon Island pit was relatively higher than the one in Caminada in the same period. Suspended mud sediment from the river, inner shelf, and bay can bypass or transport and deposit in the Caminada pit and Raccoon Island pit, which showed that the Caminada pit and Raccoon Island pits would not be considered as a renewable borrow area for future sand dredging activities for coastal restoration.

Volcanism‐induced sedimentation and model: A case study of the Upper Jurassic‐Lower Cretaceous sediments in the Liuhe‐Tonghua Basin, NE China

Understanding how the lacustrine environment adapts to volcanism and the relevant products is one of the key goals of volcaniclastic sedimentology. Mixed sediments can be deposited in lacustrine basins during the interaction between volcano and environment. This article is focus on the lithology, lithofacies, association, and sedimentary sequence of the Late Jurassic‐Early Cretaceous mixed sediments from the Liuhe‐Tonghua Basin, revealing the transportation‐accumulation processes of volcanic materials from subaerial eruption into water or subaqueous eruption mingling with terrigenous clasts. Four kinds of mixed‐sediment rocks are identified including tuffaceous sandstone, tuff‐lapilli tuff, breccia‐agglomerate/lava and tuff lava/lava, and six lithofacies associations are identified: (a) base surge and pyroclastic flow, interpreted as the middle‐distal end of a mixed‐fan delta; (b) base surge‐pyroclastic flow and turbidite flow, interpreted as the distal end of a mixed‐fan delta; (c) base surge‐pyroclastic flow‐turbidite flow and mud deposits, interpreted as a mixed subaqueous fan; (d) sand sheet of the base surge and mud deposits, interpreted as a deepwater region; (e) subaerial volcanic edifice, interpreted as a volcanic vent‐proximal slope; (f) subaqueous volcanic edifice, interpreted as a volcanic slope. These associations may exhibit different spatial occurrences and palaeogeographic distributions, representing the transition from a volcanic to a sedimentary environment in the source to sink system, and an ideal mixed sedimentation model is established based on these associations and relevant mud deposits. These associations also exhibit a typical volcanic‐sedimentary sequence including terrigenous lowstand sediments in extensional settings and mixed volcanic and terrigenous transgressive‐highstand sediments in trans‐extensional settings. This article presents a case of volcaniclastic sedimentation (mixed sedimentation) of Cretaceous volcano‐fault basin in Northeast China, which can provide a reference for the lacustrine volcaniclastic deposition in other similar genetic basins around the world.

Environmental evolution of the East China Sea inner shelf and its constraints on pyrite sulfur contents and isotopes since the last deglaciation

To better understand the depositional constraints on the sulfate reduction process, we present a set of sulfur isotope data for hand-picked pyrites (δ34Spyr) from the coarse fraction (63–250 μm) of bulk sediments, coupled with the contents of carbonate, total organic carbon (TOC) and nitrogen (TN), as well as δ13C values of the TOC, from sediments of core EC2005 on the inner shelf of the East China Sea (ECS) since 16.4 ka. Our results show that core sediments were deposited in a terrestrial environment before 13.1 ka (stage I) when pyrite rarely occurred. During stages II (13.1–12.3 ka) and III (12.3–12.1 ka) seawater began to influence the core location, forming a tidal flat environment where abundant pyrites are well preserved. Then the inner shelf of the ECS was fully flooded, and two intervals with high (stage IV:12.1–6.0 ka; stage VI: 5.2–1.5 ka) and low sedimentation rate (stage V: 6.0–5.2; stage VII: 1.5 ka-present) are identified respectively. When compared with previous δ34S values of chromium-reducible sulfur (δ34SCRS) derived from the bulk sediments, δ34Spyr values are usually higher, indicating the macroscopic pyrites form in the later stages of sedimentary diagenesis when ongoing sulfate reduction has distilled porewater sulfate to a high degree. Considering the wide occurrence of biogenic shallow gas (dominated by CH4) in these sediments, sulfate-driven anaerobic oxidation of methane (SO4-AOM) and organoclastic sulfate reduction (OSR) are expected to be two competitive pathways for sulfate reduction. We propose that the changes in sedimentation rate controls the pace of migration of the sulfate methane transition zone (SMTZ). When sedimentation rate is low, the SMTZ may be fixed in a certain depth (e.g., sediments deposited in stage III and V), where H2S is produced by SO4-AOM. In contrast, when sedimentation rate is very high (> 1 cm/yr), the SMTZ would be deep, and H2S is mostly produced by OSR. Further, our results imply that sulfur diagenesis in recent (since 1.5 ka) ECS mud sediments might be influenced by physical reworking (e.g., typhoon) and/or biological activity (bioturbation), resulting in partial reoxidation of pyrite crystals in fluid mud. Our findings therefore demonstrate that pyrite sulfur isotope compositions (bulk δ34SCRS & hand-picked δ34Spyr) are sensitive to local environmental evolution and the combined use of these two indicators can provide new insights into pathway of sulfate reduction in unsteady environments.

Dredging in an estuary causes contamination by fluid mud on a tourist ocean beach. Evidence via REE ratios

Deposits of fluid mud on wave-dominated beaches are rare. Where they happen frequently and periodically, they can be associated with anthropic processes that bring fluid mud to the shoreface and surf zone. To determine the reason for the frequent deposition of fluid mud at Cassino Beach (Southern Brazil) in the 2014–2020 period, the La/Eu and Gd/Yb ratios in marine, beach, and adjacent Patos estuary sediments were investigated. Mud from the beach showed similar ratios of REE to dredged sediments from the harbor basin and navigation channel within the estuary. Industrial and port activity changes REE ratio in sediments of the navigation channel, and they are distinct from naturally deposited marine and estuarine sediments. We conclude that the mud deposition events at the beach are most likely associated with dredging processes in the estuary especially where overflow is the source of fluid mud on the beach shoreface.

Modelling Hydrological Performance of a Bauxite Residue Profile for Deposition Management of a Storage Facility

Accurate scheduling of bauxite residue (red mud) deposition time is required in order to prevent the risk of storage facility failure. This study was conducted to precisely determine the hydraulic parameters of bauxite residue and investigate the capability of HYDRUS to accurately estimate the residue moisture profile and the timing for its deposition. The hydraulic properties of the bauxite residue profile were determined by solving an inverse problem. A one-dimensional hydrological model (HYDRUS-1D) was validated using a 300 mm long column filled with bauxite residue and exposed to a dynamic lower boundary condition. After numerical validation, the model was used to simulate the moisture profile of bauxite residue under the climatic conditions of an alumina refinery site in Queensland, Australia, as well as other scenarios (i.e., high (300 mm) and small (1.7 mm) rainfall events of the site). This study showed that the HYDRUS model can be used as a predictive tool to precisely estimate the moisture profile of the bauxite residue and that the timing for the re-deposition of the bauxite residue can be estimated by understanding the moisture profile and desired shear strength of the residue. This study revealed that the examined bauxite residue approaches field capacity (water potential −10 kPa) after three days from a low rainfall event (<1.7 mm) and after eight days from an intense rainfall event (300 mm) at the time of disposal. This suggests that the bauxite residue can be deposited every four days after low rainfall events (as low as 1.7 mm) and every nine days after high rainfall events (as high as 300 mm) at the time of deposition, if bauxite residue experiences an initial drying period following deposition.

Centurial Evolution of an Offshore Mud Deposition Area in the Changjiang (Yangtze) Estuary and Its Links to Environmental and Anthropogenic Activities

Large amounts of sediments originating from the Changjiang (Yangtze) River are deposited in the subaqueous delta and in the adjacent muddy area off the mouth and on the inner shelf of the East China Sea. The terrestrial sediments deposited in these areas not only contain information about the composition and environment of the source area, but they also record changes in anthropogenic activities. A sediment piston core (CJ0702) was extracted from the Changjiang subaqueous depocenter (31.00°N, 122.67°E) in a water depth of 22.0 m. The core was subsampled at 1–2 cm intervals and analyzed for grain size, clay mineralogy, and major element geochemistry. Results indicate a relatively high sediment accumulation rate of approximately 3.11 cmyr. These parameters exhibited only minor cyclical fluctuations in the core, which resulted from many factors. During the past 120 years, the Changjiang River-derived sediment is the primary source of sediment in the offshore mud area without evidence for the Yellow River-derived sediment increasing. After the trunk stream shifted from the North Branch to South Branch, the variations of proxies are controlled by the periodic fluctuation possibly linked to El Nino-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). In addition, anthropogenic heavy metal concentrations can be divided into three stages, which coincide well with economic development and environmental protection policies.

Modavite finds in Middle Miocene (Langhian Stage) deposits of southwestern Poland

Most of the Ries tektites (moldavites) were deposited in sediments clearly postdating the Ries crater formation. This suggests secondary deposition for these ejected glasses. Only a few sedimentary formations known to contain these tektites are of Middle Miocene age and coeval with the Ries event. One is the Poznanska Formation, which is exposed across southwestern Poland. These mud deposits formed in the Middle Miocene (Langhian Stage). New moldavites, described in this report were found in the Poznanska Formation and weigh from 0.851 to 0.907 g. The North Stanislaw sandpit, where the tektite specimens were found, is located 490 km from the Ries structure. These finds agree with the numerical simulation modelling of the ejection of these moldavites up to 600 km away from the source crater.

Observations of the distribution and flocculation of suspended particulate matter in the North Yellow Sea cold water mass

Flocculation has a great influence on the biogeochemical cycle by altering the particle size, density and settling velocity of suspended particulate matter (SPM) from coastal to shelf sea areas. However, the flocculation process in the shelf sea areas of China has not been systematically studied. In this study, the influencing mechanism of the North Yellow Sea cold water mass (NYSCWM) on the distribution and flocculation process of SPM is studied based on a comprehensive investigation during the summer of 2016. The results revealed that the mass concentration and turbidity of SPM showed a decreasing trend from coastal to offshore areas and an increasing trend from surface to near-benthic layers. Sediments from the Shandong subaqueous clinoform that were resuspended by the tidal mixing effect were the main source of inorganic SPM in the North Yellow Sea in summer. The existence of the bottom cold water mass enhanced the thermocline and pycnocline in the North Yellow Sea shelf area. The pycnocline obstructed the vertical diffusion of nutrients in the NYSCWM, resulting in a subsurface maximum chlorophyll a (chl a) layer, which further contributed to the maximum subsurface volume concentration of SPM. Flocculation was ubiquitous in the study area and was the main reason for the asynchronous variability in the mass concentration, turbidity and volume concentration of SPM. Three different kinds of flocculation mechanisms were identified, including the effects of biological activities in water masses above the NYSCWM, physicochemical effects in the near-benthic nepheloid layer within the NYSCWM, and their combined effects in shallow coastal areas. The flocculation of SPM enhanced the transport of particles from the surface to the bottom of the water column and made an important contribution to the formation of the North Yellow Sea mud deposit.

The Analysis of Total Dissolved Iron from Mud Sedimentation Ponds Wastewater in PT Bukit Asam (Persero) Tbk Tanjung Enim Using Individual Control Diagram

The tests have been carried out on the iron content of wastewater in the inlet and outlet of the mud sedimentation ponds PT Bukit Asam (Persero) Tbk Tanjung Enim, South Sumatra Province. The iron concentration in mining waste water that does not comply with government standards of 7.0000 mg / L can pollute the environment. The measurement of iron concentration was carried out by Atomic Absorption Spectrophotometer (AAS) method in accordance with SNI 06-6989.4: 2004. Analysis of iron concentration using calibration curve methods and individual control diagrams. The results of data analysis showed that the iron content of the inlet and outlet MSP (Mud Sedimentation Ponds) wastewater was still under the standard set with an average value of 1.4488 mg/L inlet and outlet 0.4061 mg/L. Based on the results of the study the concentration of iron meets the established quality standards.

Magnetic Resonance Imaging as a Novel Method for Elucidating Sediment Burrow Structures and Functions.

Burrow structures produced by various benthic animals in sediments are important components of aquatic ecosystems, allowing the circulation of interstitial water via ingress of fresh bottom water into the burrows upon feeding and intraburrow migration. Although X-ray computed tomography has been used to visualize burrow structures, it could not reveal the structures in the soft mud in Lake Kasumigaura, where evaluation of the water-circulation effect of burrows is an important issue. Here, we describe the first attempt to use magnetic resonance (MR) imaging (MRI) to visualize intact burrow structures in the soft mud sediment cores collected from a eutrophic lake. Our MRI application clarified the dynamic distribution of burrows inhabited by chironomids in the soft mud that previous studies could not visualize. By examining the relationships between the degree of chloride ion depletion in deeper layers and the burrow density calculated from the MR images, we were able to consistently explain the water-circulation effect of burrows, suggesting the higher reliability of burrow density calculated from MR images. In addition, we were able to evaluate the activity of burrows, which is difficult to achieve in sediment core experiments. We observed a smaller water-circulation effect of burrows on ammonium ions than on chloride ions, suggesting the enhancement of ammonium production or release in burrow-rich sediments.

Analisis sedimen dan pengaruhnya terhadap kondisi garis pantai di kawasan pantai timur Kabupaten Lampung Selatan

The erosion and sedimentation process that occurred in the east coast of South Lampung is a natural process affecting the balance of coastal sediment transport and resulting in the instability of coastal lines to the loss of the coastal communities along the coast, such as silting the river and can disturb the traffic of fishing boats. This is seen as a natural process influenced by the magnitude of wave energy coming, the type and size of sediment deposited, and coastal morphology. This research aims to analyze sediment and its effect on the changing coastline. The calculation approach with the empirical formula against coastal sediment data and wave data is used to predict the natural processes occurring along the coast. Analysis of SPOT 6/7 satellite imagery years 2008, 2013, 2016, and 2018 is the next step to estimate the similarity with empirical calculation results. The results showed that the East Coast had a characteristic mud sediment size ranging from 0.0258 – 0033 mm with the highest wave from the east with a wave height above 2.57 m and a period above 8,015 S. Research locations tend to undergo sedimentation processes that are influenced by waves, grain size, and there are rivers carrying sediments and deposits in the river estuary.

Mud‐associated organic matter and its direct and indirect role in marsh organic matter accumulation and vertical accretion

AbstractIn situ plant production is often assumed to be the major contributor to organic matter (OM) accumulation and vertical accretion in tidal marshes. Here, we evaluate the contribution of mud‐associated OM in salt and brackish marshes in Louisiana. Based on 14 soil cores, the OM content of the mud fraction—i.e., any material smaller than 64 μm—was 17% ± 7% for the salt marshes and 28% ± 14% for the brackish marshes. This remains nearly uniform over the top 35 cm depth, suggesting that this material is deposited contemporaneously with the mud. The dry bulk density of the mud (300–450 kg m−3) is also much lower than what was estimated using a previously proposed two‐constituent mixing model (1990 kg m−3). To reconcile this discrepancy, we developed a modified mixing model that includes mud OM and differentiates sand as a separate constituent with its high dry bulk density. The model estimates that mud contributes to ~ 60% of the total marsh vertical accretion in Louisiana, considerably higher than the ~ 14% estimated with the two‐constituent mixing model. The result, which is a direct consequence of the relatively high porosity of mud, highlights that mud deposition is crucial for the accretion of microtidal marshes. Further, the model estimates that the mud OM constitutes ~ 60% of the total soil OM, emphasizing that in situ plant production is not the only—and, in minerogenic marshes, not the major—contributor to OM accumulation.

Fluid Mud Measurement and Siltation Analysis in A Trial Excavated Channel in the Approach Channel of the Xiangshan Port

In order to clarify the distribution and variation of silt and fluid mud in the Waiganmen shallow section of the 50000-ton intake channel of the Xiangshan Port, and to understand the influence of the channel excavation on the surrounding flow conditions and the strength of the backsilting, especially the impact of typhoon on the sudden silting of the channel, so as to demonstrate the feasibility and stability of the channel excavation. The fluid mud, hydraulic, sediment and topographic measurements were carried out in the study area, and the thickness of the fluid mud layers, tidal current, sediment and topographic data were obtained. Dual-frequency sounder, gamma-ray densitometer and SILAS navigational fluid mud measurement system were used to monitor the fluid mud, and the results were compared and verified. The adaptability and accuracy of the three methods were analyzed. The SILAS navigational continuous density measurement system and gamma-ray fixed-point fluid mud measurement are used to detect the density, thickness and variation of the fluid mud accurately. Based on the hydrological observation data, the process of erosion and deposition in excavation channel and its influence mechanism are analyzed, and the distribution characteristics and evolution law of siltation in engineering area are given in the form of empirical formula. The research shows that the super typhoon can produce large siltation, which results in sudden siltation of the channel. The tidal current is the main dynamic factor of the change of erosion and siltation of the excavation trench. Under the influence of reciprocating tidal current and excavation topography, the trial excavation trench is silted on the whole. There is fluid mud in the monitoring area of the trench, and the distribution of fluid mud is different in space. The thickness of the fluid mud at the bottom of the trench is generally larger than that outside the trench and the slope of the trench, and the siltation of the trench tends to be slow. The research results can provide scientific evaluation for channel excavation and maintenance, and support for the implementation of the project.

Organic Carbon and Carbonate System in the Bottom Sediments of Shallow Bights of the Peter the Great Bay (Sea of Japan)

Abstract—The diagenesis of organic matter (OM) is studied in bottom sediments taken in February, 2018 from therapeutic mud deposits of the Uglovoi Bay and Voevoda and Ekspeditsiya bights (Peter the Great Bay, Sea of Japan). The carbonate system of bottom sediments and pore water were analyzed for the contents of nutrients, dissolved organic carbon, humic substance, and concentrations of sulfates and chlorides. The concentrations of organic carbon, chlorophyll-a, humic and fulvic acids, and mobile sulfide species are measured in a solid phase of sediment. Underwater photographing shows that sampling localities are covered by Zostera marina meadows in the Voevoda and Ekspeditsiya bights and by diatom mats in Uglovoi Bay. The proportions between dissolved inorganic carbon and alkalinity, as well as data on sulfate–chlorine ratios and mobile sulfide species indicate that the OM degradation in bottom sediments is mainly controlled by sulfate reduction. The Uglovoi Bay and Voevoda and Ekspeditsii bights are characterized by different values of bioturbation coefficients: 3.0, 107.6, and 14.5 cm2/day, respectively. The estimated fluxes of organic carbon from water into sediment and of dissolved inorganic carbon from sediment into water significantly differ. The disbalance between organic and inorganic carbons can be caused by the following reasons: (a) ignored CO2 flux released by marine organisms from bottom sediments through their siphonal system; (b) partial OM consumption in food with its subsequent deposition in it.

Metavirome and its functional diversity analysis through microbiome study of the Sikkim Himalayan hot spring solfataric mud sediments.

Viruses are the most prodigious repertory of the genetic material on the earth. They are elusive, breakneck, evolutionary life particles that constitute a riveting concealed world. Environmental viruses have been obscurely explored, and hence, such an intriguing world of viruses was studied in the Himalayan Geothermal Belt of Indian peninsula at Sikkim corridor through hot springs. The hot springs located at the North Sikkim district were selected for the current study. The solfataric mud sediment samples were pooled from both the hot springs. The virus community showed significant diversity among the two hot springs of Yume Samdung. Reads for viruses among the mud sediments at Old Yume Samdung hot springs (OYS) was observed to be 11% and in the case of New Yume Samdung hot springs (NYS) it was 6%. Both the hot springs were abundant in dsDNA viromes. The metavirome reads in both the OYS and NYS hot spring mud sediments showed the predominance of Caudovirales; Herpesvirales; Ortervirales among which viral reads from Siphoviridae, Myoviridae, Phycodnaviridae and Podoviridae were abundantly present. Other viral communities belonged to families like Baculoviridae, Mimiviridae, Parvoviridae, Marseilleviridae etc. Interestingly, in the case of NYS, the unassigned group reads belonged to some unclassified giant DNA viruses like genera Pandoravirus and Pithovirus. Other interesting findings were - reads for Badnavirus having ds (RT-DNA) was exclusively found in NYS whereas Rubulavirus having ss(-)RNA was exclusively found in OYS sample. This is the first ever report on viruses from any hot springs of Sikkim till date.

Yield stress measurements of mud sediments using different rheological methods and geometries: An evidence of two-step yielding

Yield stress materials have a wide range of commercial applications. Yet, the suitable way of determining the yield stress values of a given material has been the subject of many studies and debates. Yield stresses are dependent on the material (shear) history and composition, which implies that robust protocols should be developed to study the yield stress dependence on a given parameter. In this study, three natural mud samples from a port having different densities were chosen for analysis. Four different geometries including concentric cylinders (Couette), cone and plate, parallel plates, and vane geometries were used. Our aim was to find the geometry and measurement protocol that best adapted to natural mud samples: the measurement should be reasonably fast and the major changes in sample structure (two-step yielding) should be recorded within the same measurement. Various rheological experiments such as stress sweep, oscillatory amplitude sweep, creep and stress growth tests were tested. Two-step yielding behavior was observed for the mud samples in stress sweep and amplitude sweep tests. The first yield point was linked with the breakage of interconnected network of aggregates/flocs while the second one was attributed to the collapse of aggregates into the smaller flocs or individual particles. Stress sweep tests proved to be practical, time efficient, and reliable tests for measuring yield stress values. Our study showed that Couette and parallel plate geometries are the most suitable geometries for analyzing the two yield stresses of the samples. Vane geometry is appropriate to study consolidated (solid-like) systems as for these samples a Couette geometry cannot be used because the bob could get stuck during the experiment.

Heterogeneous electro–Fenton using three–dimension NZVI–BC electrodes for degradation of neonicotinoid wastewater

Neonicotinoids (NEOs), as the most widely used pesticides, pose a serious threat to water ecosystems, especially clothianidin (CLO). However, the degradation behavior of CLO, as a new type of persistent organic pollutant, is rarely studied in wastewater treatment. To bridge this gap, heterogeneous electro-Fenton system using three-dimension electrodes made of biochar-supported zero-valent iron nanoparticle hybrid material (NZVI–BC), abbreviated as 3D–ICE–EF system, is invented and initially applied in CLO wastewater degradation, without the addition of Fenton reagent. NZVI–BC in 3D–ICE–EF system can concentrate CLO on electrodes by excellent adsorption and effectively eliminate it to achieve self-cleaning effect. In addition, the deposition of iron mud (Fe(OH)3) and the circular utilization of Fe in Fenton system is effectively improved by the addition of hydroquinone (HQ) in 3D–ICE–EF system. The pH applicable scope of Fenton system is extended to alkaline condition by the applications of NZVI–BC electrodes. The increase in the acidity of electrolyte is considered the primary reason of the high degradation efficiency of CLO in 3D–ICE–EF system at an initial pH of 9.0. The degradation performance of 3D–ICE–EF system tends to be promoted by the increase of current intensity and air flow rate. Seven plausible mechanisms of CLO degradation were identified in 3D–ICE–EF system. The ecotoxicity evaluation of degradation products indicated that CLO degradation in 3D–ICE–EF system exhibits a remarkable tendency to reduce toxicity levels.

Facies analysis and palynology of upper Miocene to Pliocene sediments exposed at Timika–Tembagapura section, Papua, Indonesia

This study reports on the recent sedimentological and palynological analysis of the rock unit outcropping at the road between Timika and Tembagapura from KM 73 to KM 92, Papua, Indonesia. The unit has been previously regarded as being late Proterozoic to Permian in age. Sedimentary facies analysis suggests a non-channelised deep-lacustrine slump and debris-flow dominated environment consists of delta front, slump, debrite, turbidite and lacustrine mud deposits. New palynological data designated a late Miocene to Pliocene age for the analysed samples, based on the occurrence of Nothofagus brassii type pollen, Stenochlaena milnei type spores (Stenochlaenidites papuanus), Dacrycarpus pollen (Dacrycarpites australiensis) without Proteaceae pollen (Proteacidites spp.). The palynomorph assemblage is interpreted to consist of two main groups: autochthonous and allochthonous components. The autochthonous component is dominated by freshwater algae with the co-occurrence of diatoms, freshwater sponge spicules, Pseudoschizaea, testate amoebae and aquatic plants. The allochthonous pollen component is derived from five major vegetation types: lowland rain forest, lower montane forest, upper montane forest, swamp forest and scrub/grassland. The palynomorph assemblages support the notion of a fluvial–lacustrine depositional environment in an inland position away from marine influences. Furthermore, the studied rock unit is considered to be deposited in the piggyback basin between Papuan Fold and Thrust Belt during the Central Range orogeny. KEY POINTS The section has been previously regarded as being late Proterozoic to Permian in age. New palynological data indicate a late Miocene to Pliocene age for the analysed samples. Sedimentological features and palynomorph assemblages suggest a fluvial–lacustrine depositional environment in an inland position away from the influence of the sea. The studied rock unit is considered as being deposited in the piggyback basin between Papuan Fold and Thrust Belt during the Central Range orogeny.

Tropical cyclone deposits in the Pliocene Taiwan Strait: Processes, examples, and conceptual model

The characteristics of tropical cyclone (TC) deposits are highly variable, and in the shallow waters of straits their character has not been established. Multiple coarse-grained beds in lower Pliocene strata in the Western Foreland Basin of Taiwan are interpreted as TC deposits, and the sedimentology of these beds reflects evolving TC processes and storm stages. By comparing sedimentological data from these beds with previous research on TCs, and with analysis of TCs that cross Taiwan from east to west, a conceptual model is built for understanding deposition in the Taiwan Strait during tropical cyclones.Taiwan is impacted by more than three TCs per year, including more than two super-typhoons every 10 years. These storms can deliver immense volumes of rain over very short time periods and are associated with intense winds. During TCs, and in shallow water in the Taiwan Strait (10–35 m water depth), hyperpycnal discharge, strong bottom currents, and oscillatory wave motion all impact deposition. These processes are manifested in the resulting deposits, and we propose that the best sedimentological criteria for recognizing TC deposits, include: 1) a basal scour surface; 2) an absence of within-bed bioturbation; 3) trough cross-stratification that preserves multi-directional, mainly shore-parallel flow with a 180° change in flow direction; 4) preservation of oscillatory structures towards the top of the bed; and, 5) organic lamina and clasts throughout the bed. Mudstone intercalated with trough cross-stratification is also a useful indicator of TC deposition as it probably reflects wave- and current-redistribution of sediment delivered to the strait through hyperpycnal and hypopycnal discharge from rivers. Contemporaneous mud deposition within TC beds is manifested as mudstone drapes on foresets and toesets, and discontinuous mudstone beds between trough cross-stratified sandstone beds. While not all TC beds exhibit all sedimentological characteristics, we hypothesize that high-probability TC beds should show three or more of them.