Development Of Deposits Research Articles

A transition from porphyry Mo to vein-style Zn-Pb mineralization: Insights from hydrothermal fluid evolution of the Chalukou deposit, NE China

To reveal the hydrothermal evolution from porphyry Mo to vein-style Zn-Pb mineralization, the Chalukou deposit in NE China with these two typical mineralization overprinted is selected for detailed research. From early to late hydrothermal veins, the quartz cathodoluminescence intensities change from bright to dark and the textures also evolve. The Ti concentrations of quartz in these veins change from high to moderate and then to low values. The fluid inclusion petrography, microthermometry and stable isotope analyses indicate intermediate-density magma-derived fluids (δ18Owater = +4.7 to + 6.2‰, δD = −132 to −136‰) exsolved at high temperatures (560° to 600 °C) with low to moderate salinity (2.4 to 8.0 wt% NaCl equiv) containing minor CO2 (<5.7 mol %). Early minor molybdenite occurred under lithostatic conditions at high temperatures (540° to 580 °C) during fluids pH change and early magnetite precipitation. Later main molybdenite precipitation at moderate temperatures (350° to 430 °C), result from fluid cooling and involving of meteoric water under the transition from lithostatic to hydrostatic conditions. The precipitation of pyrite in transitional veins at moderate temperatures (330° to 420 °C), and the late sphalerite-galena from a lower-temperature fluid (180° to 300 °C) is consistent with the cooling of magmatic fluid, and gradually dilution with meteoric water under hydrostatic conditions. It is deduced the transition from porphyry Mo to vein-style Zn-Pb mineralization is likely driven by progressive decrease in temperature of the magmatic fluids and the increasing influx of meteoric water.

Paleo-uplift forced regional sedimentary evolution: A case study of the Late Triassic in the southeastern Sichuan Basin, South China

The sedimentary environment of the Upper Triassic in the southeastern Sichuan Basin is obviously controlled by Luzhou paleo-uplift (LPU). However, the influence of paleo-uplift on the sedimentary patterns of the initial stages of this period in the southeastern Sichuan Basin has not yet been clear, which has plagued oil and gas exploration and development. This study shows that there is a marine sedimentary sequence, which is considered to be the first member of Xujiahe Formation (T3X1) in the southeastern Sichuan Basin. The development of LPU resulted in the sedimentary differences between the eastern and western Sichuan Basin recording T3X1 and controlled the regional sedimentary pattern. The western part is dominated by marine sediments, but the eastern paleo-uplift area is dominated by continental sedimentation in the early stage of T3X1, and it begins to transform into a marine sedimentary environment consistent with the whole basin in the late stage of the period recorded by the Xujiahe Formation. The evidences are as follows: (1) time series: based on the cyclostratigraphy analysis of Xindianzi section and Well D2, in the southeastern Sichuan Basin, the period of sedimentation of the Xujiahe Formation is about 5.9 Ma, which is basically consistent with the Qilixia section, eastern Sichuan basin, where the Xujiahe Formation is widely considered to be relatively complete; (2) distribution and evolution of palaeobiology: based on analysis of abundance evolution of major spore-pollen, many land plant fossils are preserved in the lower part of T3X1, indicates the sedimentary environment of continental facies. In the upper part of T3X1, the fossil of terrestrial plants decreased, while the fossil of marine and tidal environment appeared, this means that it was affected by the sea water in the late stages of T3X1; (3) geochemistry: calculate the salinity of water from element indicates that the uplift area is continental sedimentary environment in the early stage of T3X1, while the central and western areas of the basin are marine sedimentary environment. Until the late stage of T3X1, the southeast of the basin gradually turns into marine sedimentary environment, consisting with the whole basin; (4) types of kerogen: type Ⅲ kerogen representing continental facies was developed in the early stage of T3X1 in the uplift area, and type Ⅱ kerogen, representing marine facies, was developed in the late stage; while type Ⅱ kerogen was developed in the central and western regions of the basin as a whole in T3X1. This study is of great significance for understanding of both stratigraphic division and sedimentary evolution providing theoretical support for the exploration and development of oil and gas.

Sedimentary evolution and lake level fluctuations of Urmia Lake (north‐west Iran) over the past 50 000 years; insights from Artemia faecal pellet records

AbstractA 25 m long sediment core from hypersaline Urmia Lake (north‐west Iran) was studied for the Late Quaternary depositional history and palaeoclimate variations using the abundance and compositional characteristics of Artemia faecal pellets. Sediment analysis is supported by scanning electron microscopy – energy dispersive X‐ray spectroscopy, organic and inorganic carbon content measurements, and stable isotopes (δ13C and δ18O) from faecal pellet carbonates. The imprecise chronology of the core back to 50 kyr bp is supported by ten radiocarbon ages from faecal pellets and bulk sediments. The palaeoenvironmental record is subdivided into four periods: (i) During much of Marine Isotope Stage 3, a period of lake level lowering is characterized by a decreasing amount of faecal pellets, and an increasing amount of coated grains, sulphate minerals and reworked shell fragments. (ii) During late Marine Isotope Stage 3 and early Marine Isotope Stage 2 a lake level lowstand and a lake floor exposure is interpreted based on the relatively low abundance of pellets, which are multicoloured and appear together with volcanic lithics and rounded sulphate minerals. (iii) During late Marine Isotope Stage 2 the record is devoid of pellets but dominated by large sulphate crystals suggesting a prolonged low lake level. (iv) During Marine Isotope Stage 1 a relative lake level highstand is rapidly established with sediments that are highly abundant in fresh pellets. The modern lake level lowstand is represented by a salt crust. The δ13C and δ18O records measured from faecal pellet carbonates suggest a link with the precipitation versus evaporation balance in the lake over time. From bottom to top the linear trend towards more negative delta values illustrates the increasing amount of precipitation arriving at the lake from the Late Pleistocene to the Holocene. Two prominent isotope minima during the Late Pleistocene and one prominent minimum in the early Holocene mark relative high lake levels, which can also be linked to Lake Van in Turkey.

New constraints on the Late Miocene-Pliocene deformational and depositional evolution of the Eastern Cordillera and Sub-Andean Zone in Southern Peru

The deformation history of the Eastern Cordillera (EC) and Sub-Andean Zone (SAZ) of southern Peru is critical for understanding the roles that tectonics and climate played in the erosional exhumation of bedrock and the associated sediment flux delivered to the Amazon drainage basin. In this study, we report new field and subsurface data, apatite fission track (AFT) and (U–Th)/He thermochronological ages, U–Pb ages on detrital zircon grains, Sr–Nd isotopic compositions of fine sediments, which combined with previously published data, provide new constraints on the Neogene deformation and deposition history across the southern Peruvian EC and SAZ between 12° and 14°S. Late Miocene-Pliocene deformation is recorded by AFT and AHe ages in both the EC and SAZ and by growth strata geometry in the SAZ. This period is characterized by the development of piggy-back synclines and duplexes in the SAZ, overthrusting of the EC, and input of recycled sedimentary rocks of the SAZ and first cycle sediments from Triassic Plutonic rocks from the EC to the late Miocene-Pleistocene piggy-back syncline sediments. We report a transition from low-energy sand-dominated to high-energy conglomerate-dominated deposits in the Plio-Pleistocene marking an increase in sedimentation rates, indicating that the thrust wedge has continued to propagate. Our data agrees with that of previously published studies and indicate that the Late Miocene-Pliocene was a period of tectonic uplift and deformation in both the EC and SAZ.

Heavy mineral constraints on the evolution and provenance of upper Permian and lower Triassic siliciclastic deposits of the Central European Basin

Heavy mineral constraints on the evolution and provenance of upper Permian and lower Triassic siliciclastic deposits of the Central European Basin

Simulation of Hydrate Particles Aggregation and Deposition in Gas-Dominated Flow

Summary Owing to low-temperature and high-pressure production environments, hydrate generation, accumulation, and deposition are prone to occur in deepwater oil and gas production wells and transportation pipelines, leading to pipeline blockage and threatening the safety of oil and gas production. To explore the aggregation mechanism and deposition law of hydrate particles in the main gas diversion pipeline, this study considered the adhesion effect of hydrate particles and established a hydrate particle aggregation and deposition model based on theory and experiments. The coupled computational fluid dynamics-discrete element method (CFD-DEM) is used in the simulation calculation. The simulation results were compared with the relevant experimental results, and maximum and average errors of 9.48% and 4.56% were observed, respectively. It was found that the main factor affecting the aggregation of hydrates is the adhesion between particles. As the subcooling temperature increased, the aggregation and adhesion of the hydrate particles increased to varying degrees. The tangential adhesion force between the hydrate aggregate particles was significantly greater than the normal adhesion force, and the adhesion force between the particles gradually increased from the surface to the interior of the aggregates. The coordination number of the hydrate particles can quantitatively characterize the degree of aggregation and is affected by many factors, such as adhesion. By studying the particle coordination number, the evolution of hydrate accumulation and deposition under different conditions can be summarized. Based on the simulation results, the mathematical relationship between different dimensionless numbers and hydrate deposition ratio (HDR) was calculated, and an expression that can predict the HDR was obtained, with an average relative error of 10.155%. This study provides a theoretical basis for predicting the aggregation and deposition of hydrate particles in gas-dominated systems and a reference for the development of hydrate prevention and control plans.

Analysis of the driving factors of the change of erosion-deposition in the Minjiang Estuary, Southeast China

Understanding the evolution and driving factors of sedimentation and erosion at the mouths of small and medium-sized mountain streams during various periods is essential for regional spatial utilization, development, and sustainable economic growth. This is particularly important when considering the combined impact of climate change and human activities. This paper presents an analysis of the changes in sedimentation and erosion of mouth isobaths and underwater deltas over different periods using nautical chart data (1950-2019) and analyzes the factors driving changes in sedimentation and erosion during different periods from 1950 to 2020 based on the runoff-sediment discharge of the Minjiang River (MR) and extreme climate factors such as typhoons, especially the driving factors that caused a sudden change in the sedimentation and erosion process between 1998 and 2005. The results indicate that runoff-sediment characteristics are crucial in driving sedimentation and erosion changes. In the past 70 years, the underwater delta of the MRE has mainly experienced four stages: deposition (1950-1992) -erosion (1993-1998) -deposition (1998-2011) -erosion (2011-2019). Taking the impoundment operation of the Shuikou Reservoir in 1993 as the node, the sediment load of the Minjiang River into the sea began to decrease sharply, and then the estuary quickly showed a state of erosion. The change of sediment flux into the sea is the main driving factor for the evolution of erosion and deposition in the Minjiang River Estuary (MRE). The critical value of the erosion-deposition transition is about 570.3 × 104 t/yr. After the estuary entered a state of erosion in 1993-1998, significant siltation suddenly occurred in 1998-2005. The reason for the siltation in this period may be related to the frequent transit typhoons and flood events in 1998-2005. Therefore, the change of river sediment supply into the sea is the main driving factor controlling the erosion and deposition evolution of the Minjiang River estuary on a long time scale of more than 10 years, which reflects the influence of large-scale human activities on the river and estuary area in the past half century. Extreme climate events are the incentive to adjust the estuary landform in the short term. Extreme climate events will not fundamentally change the process of estuarine geomorphological evolution under the background of sediment supply reduction.

Evolution of Cenozoic sedimentary architecture in Central and Southern South China Sea basins

The Central and Southern South China Sea (CSSCS) has a complex tectonic dynamic background and abundant oil and gas resources, which has always been a hot topic of academic and industrial attention. However, systematic analyses are still lacking regarding its sediment filling structure and evolution, mostly due to limited borehole penetration and poor quality of seismic reflection data for deeply buried sequences. No consensus has been reached yet on the sedimentary infilling processes, which impeded the reconstruction of the palaeogeography of Southeast Asia and the oil-and-gas exploration undertakings. Here, we illustrate the Cenozoic sedimentary evolution of the CSSCS region by synthesizing relevant data from previous literature and our own observations and displaying the evolution of depositional systems in sequential reconstructions. Besides, the controlling factors of preferred sedimentary scenarios in the CSSCS incorporate the latest interpretations of the spreading of South China Sea (SCS) as well as the demise of the hypothetical Proto-South China Sea (PSCS). The results show that there are three types of sedimentary basins in the CSSCS (foreland, strike-slip, and rift basins) with different sedimentary filling structures. The foreland basins formed a depositional pattern of ‘transition from deep water to shallow water environments’, dominated by deep-water depositional systems which were formed before the Early Oligocene with submarine fans developed. Later, the foreland basins were gradually dominated by shallow-water depositional systems with deltas and shallow marine facies. The strike-slip basins showed the depositional architecture of ‘transition from lake to marine environments’, i.e. the basins were dominated by lacustrine deposits during the Eocene and evolved into the marine depositional environment since Oligocene with delta developed in the western part of the basin. The depositional evolution of rift basins illustrated the characteristics of ‘transition from clastic to carbonate deposits’, i.e., the rift basins were dominated by Eocene–Oligocene shallow marine clastic depositional systems, while carbonate platforms started to develop since the Early Oligocene from east to west. The above-mentioned differences of depositional architecture in the CSSCS were controlled by the scissor-style closure of the PSCS and the progressive-style expansion of the SCS. Specifically, the early-period deep-water sedimentary environment of CSSCS basins was controlled by the distribution of PSCS in the Eocene. As the scissor-style closure of PSCS progressed from west to east during the Oligocene to Early Miocene, the northwest of Borneo continued to rise, providing a great number of clastic materials to the basins and gradually developing large-scale deltas from west to east. The distribution of early-period lacustrine sedimentation of strike-slip basins was affected by paleo uplift, and the basins transgressed from the northeast and gradually evolved into marine sedimentary environment due to the expansion of SCS. The expansion of SCS also controlled the sedimentary filling evolution of the rift basins, which broke away from the South China continent and drifted southward. Thus, the rift basins lacked the supply of terrigenous clastic sediments which hindered the development of large-scale deltas and formed a clear water environment conducive to the development of carbonate platforms from east to west.

Atmospheric deposition of microplastics in Shiraz, Iran

The atmosphere plays a critical role in the regional and global transportation and redistribution of microplastics (MPs). However, the significance of rainfall and its means of scavenging MPs are not well understood. In this study, MP deposition was determined during successive dry and rainy events over eight consecutive days in the Shiraz region of Iran. Flux magnitudes and temporal distributions at six sites within and outside the city (including a remote, non-urbanised location) were similar and revealed a progressive increase in MP abundance and deposition during dry periods (up to about 50 MP m−2 h−1) and subsequent relatively rapid wet deposition (washout) by incipient rainfall (peaking at about 130 MP m−2 h−1). Wet deposition of MPs progressively decreased throughout the rainfall event, but with evidence of secondary peaks, before atmospheric accumulation and dry deposition increased during the next dry event and the cycle continued. Dry and wet deposition were dominated by fibres (that included polyester-polyethylene terephthalate, polystyrene, polyvinyl chloride and polyethylene) but the evolution of deposition did not appear to be associated with changes in MP size. These observations indicate that, as with other airborne pollutants, initial rainfall is an efficient scavenger of atmospheric MPs. Along with variations in methodology, this effect may contribute to the wide variation in MP fluxes reported in the literature.

Paleoenvironmental Significance of Claystone in the Middle Ordovician Miboshan Formation of Ordos Basin, China: Evidence from Trace Elements

The Miboshan Formation in the Middle Ordovician plays a crucial role in the sedimentary evolution of the western margin of the Ordos Basin as it represents the transition from a carbonate platform to a deep-water slope-basin environment. This study focuses on the paleoenvironment of claystone in the Middle Ordovician Miboshan Formation, located in the Ningxia Hui Autonomous Region of the Ordos Basin. The study aims to analyze the influence of sea level and salinity on rare earth elements, investigate terrigenous input and redox conditions through trace element analysis, and exemplify the coupling relationship between depositional and tectonic environments. The Miboshan Formation profile consists of thick- to thin-bedded limestones, mainly composed of lenticular calcirudite with erosion surfaces and horizontal laminae. Grayish black claystone have deformation structures and graptolite fossils. Based on the total number of rare earth elements and the trace element indexes, the seawater properties, redox degree, and terrigenous input are located in two data sets in different parts of the profile (i.e., sample 6-1 to 6-5: Concentrated in lower part, and samples 6-6 to 6-8: Concentrated in upper part), implying that they were deposited at different subaqueous uplifts. Negative Ce anomalies, La/Ce, V/Cr, and Fe3+/Fe2+ ratios indicate an anoxic condition with stratified redox structure, whereas characteristic LaN/NdN, Y/Ho, and Sr/Ba suggest deep-water affected by fresh water. The ∑REEs and Th/U ratios indicated that the study area was mainly deposited from terrigenous materials in the stable tectonic area. According to the ages of deposition, lithologic analyses, and chemical parameters, the Miboshan Formation is related to the deep water environment in a ponded basin influenced by subaqueous uplift resulting from plate subduction in an active continental margin. This study provides valuable insights into paleoenvironment and paleotectonic environments of the Miboshan Formation in the Middle Ordovician.

Evolution of carbon deposits during ethylene aromatization over Zn/ZSM-5

Zn/ZSM-5 catalysts exhibit remarkable catalytic activity in the ethylene aromatization process. Nonetheless, they frequently suffer from rapid deactivation owing to coke deposition. This study investigated the coking process of Zn/ZSM-5 catalyst during the ethylene aromatization, as well as the evolution of carbon deposits and their impact on the catalyst's structure and surface properties. The results showed that, despite ethylene conversion remaining at 100 % during the initial high-activity stable phase (0–24 h), even small amounts of carbon deposition resulted in significant decrease in microporosity and strong acid sites of the catalyst. Methyl-substituted benzene was identified as the primary deposit on the catalyst in the initial reaction stage, as confirmed by infrared (IR) spectroscopy, ultraviolet-Raman (UV-Raman), thermogravimetry-mass spectrometer (TG-MS), gas chromatography-mass spectrometry (GC–MS), and electron paramagnetic resonance (EPR), which can act as an active hydrocarbon pool species for ethylene oligomerization. Thus, the catalyst was able to maintain high ethylene conversion activity despite the loss of some acid sites. However, during the decline in activity period (24–72 h), the composition and location of carbon deposits underwent significant changes. A large number of polycyclic aromatic hydrocarbons formed on the catalyst surface, which resulted in the weakening of the interaction between Zn species and the zeolite, ultimately leading to the transformation into large grain ZnO and decrease in aromatics selectivity. Additionally, the bulky carbon deposits covered the pores of the zeolite, leading consequently to a decrease in ethylene conversion and ultimately catalyst deactivation.

Characterization of the Sedimentary Environment of the Shanxi Formation in the Southeastern Ordos Basin Revealed by Detrital Zircon and Geochemical Analyses

The interpretation of the sedimentary paleogeographic environment of the Lower Permian Shanxi Formation (P1s) coal strata in the southeastern Ordos Basin remains a subject of significant debate. In this paper, based on detrital zircon U–Pb source analysis, paleosalinity assessment, the sandstone modal composition, and other methods, we analyzed the P1s source system and constructed a model of the sedimentary evolution. The findings reveal that the primary source of the clastic materials in the study area stems from a mixed-source within the recycling orogenic belt. During the deposition period, the Shanxi Formation developed two predominant material source systems: one in the north, primarily linked to the Paleo-Yinshan Fold Orogenic Belt (YFOB), and the other in the south, originating from the North Qinling Orogenic Belt (NQinOB). These two major source systems converged in the Yichuan–Fuxian area. From the early stages of the Shanxi Formation period (Shan1), there was a regional retreat of the sea in the area. The seawater receded in a southeastward direction, leading to a gradual reduction in the paleosalinity and Sr/Ba-ratio variability during the Shan1 period. The influence of the seawater diminished, transitioning into a deltaic depositional system. This shift towards a terrestrial lakeshore basin reached its full development during the Lower Xiashihezi period. This study concludes that the Shanxi Formation in this area represents the evolution of a deltaic depositional system originating from a shallow sea shelf. This evolution can be divided into three major stages: remnants of the shallow sea shelf, barrier island–lagoon–littoral, and deltaic deposition. Within this framework, the shoreline underwent frequent lateral migration, influencing a broad range of characteristics. In the vertical direction, numerous alternating sets of sandstone bodies and mudstone, shale, and coal beds formed, creating a significant relationship between coal hydrocarbon sources and reservoirs. This study also establishes the stratigraphic-sequence framework of the basin for this period. These results hold great importance for the expansion of natural gas exploration and development efforts.

Depositional evolution of Eocene deep-lake mudrock lithofacies driven by astronomical forcing in the Dongying Depression, China

With the deepening of shale oil and gas exploration and development, researchers are more eager to understand the depositional evolutionary pattern of mudrock lithofacies, and the astronomical cycle is an important mechanism driving the depositional evolution of mudrock. In this paper, stratigraphy is divided based on astronomical cycle, and a stratigraphic sequence is established by using long eccentricity and precession cycles to dissect well sections with cores in the connecting well profiles. The relationship between the type of lithofacies development in response to the long eccentricity cycle is found. The lake basin mainly developed mudstone-dominated facies during high-value periods of long eccentricity, while sandstone facies developed in the slope zone and marl facies developed in the deep-lake zone during low-value periods. The relationship between lithofacies subcycles and amplitude variations in precession within the long eccentricity cycles has been determined. Sandstone or marl developed during periods of maximum precession, while mudstone developed during periods of minimum precession. The model of climate and depositional cycles controlled by long eccentricity and precession has been summarized. First, during periods of low long eccentricity, the amplitude of precession is small. This leads to cold and arid climates with reduced rainfall, resulting in less terrestrial input to the basin and a period of contraction. During periods of high long eccentricity, the climate is hot. This leads to hot and humid climates with increased rainfall, resulting in stronger terrestrial input to the lake basin and a period of expansion. Second, the amplitude variations in precession also affect the strength of terrestrial input. During periods of maximum precession, the received solar radiation is low, resulting in a dry and cold climate with reduced rainfall, weakening the terrestrial input to the basin. During periods of minimum precession, the received solar radiation increases, resulting in a hot and humid climate with increased rainfall, strengthening the terrestrial input to the basin. This study systematically investigates the depositional model and factors controlling the mudrock layers in the research area. The research results can contribute to the prediction of “sweet spots” for shale oil and gas and provide references for similar sedimentary basins.

Facies association analysis of a Toarcian siliciclastic‑carbonate lacustrine system, Sichuan Basin, China

Globally, considerable coverage has been devoted to marine environment affected by the Jenkyns Event, but little attention has been given to lacustrine system. Here, siliciclastic‑carbonate samples of the Da'anzhai Member (J1dn) were examined for petrology and geochemistry in order to evaluate lithofacies characteristics, depositional processes and environmental changes of the palaeo-Sichuan lacustrine basin contemporaneous with the Jenkyns Event. Unique sedimentological and petrological features were used to identify five principal facies associations (FA) and depositional environments, including the distal delta front, accretionary bioclastic shoals, proximal bioclastic shoal ramp, distal bioclastic shoal ramp and (semi-)deep lacustrine environment. The vertical transitions of FA reveal that J1dn forms a complete lacustrine transgressive-regressive sedimentary system during the Toarcian, which can be further divided into 3 units in combination with standard gamma logging. The lower unit is characterised by frequent intermixing of multiple FA interpreted as frequent lake-level fluctuations. The middle unit is characterised by the deposition of clay-rich mudstone and the demise of bioclastic shoals interpreted as intensive lacustrine transgression that were at times affected by storm-induced waves or oscillatory currents coinciding with the initiation of the Jenkyns Event. The upper unit is characterised by the thicker and higher proportion of biogenic carbonate-rich lithofacies interpreted as the lake regression, contemporaneous with the end of the Jenkyns Event. Overall, clay-rich lithofacies from suspension settling, turbidity current or slumping triggered by storm events were deposited during a high relative lacustrine-level, accompanied by organic carbon-rich deposition and preservation. In contrast, carbonate-rich lithofacies were mainly controlled by biogenic carbonate sedimentation, associated with a low relative lacustrine-level unconducive to organic matter accumulation. Finally, the proposed depositional evolution model at the lake-level highstand stage and lowstand stage of the palaeo-Sichuan lacustrine basin provides new insights and understanding on the changing palaeolimnological history of the Toarcian lacustrine system.

Comparativestudy of experimental thermographic data and finite element analysis on temperature evolution of PET-G layer deposition during additive manufacturing process

Comparativestudy of experimental thermographic data and finite element analysis on temperature evolution of PET-G layer deposition during additive manufacturing process

Sedimentary evolution of the western North Yellow Sea mud patch: A Holocene perspective

The western North Yellow Sea mud patch has a unique location, abundant sediment supply and a complex sedimentary environment. Reconstructing its sedimentary evolution is crucial for a comprehensive understanding of source to sink process in the North Yellow Sea. Using core W03 collected from the mud patch, this study unravels its Holocene history through analysis of sedimentology, mineralogy and micropalaeontology. The results indicate that core W03 can be divided into three depositional units (DU). DU3 (538-461 cm) is composed of earthy yellow clayey silt and characterized by a hard layer. It was formed in the near-coast environment between 10.3 and 9.8 cal kyr BP, a hiatus period between Melt Water Pulse 1B and 1C events. DU2 (460-341 cm) was formed during the period of 9.8–6.5 cal kyr BP. As sea level rose, the westward retreat of the Yellow River mouth caused the transportation of Yellow River-derived sediment over longer distances, leading to an increase in flaky minerals. The rising sea level also induced a shift towards a reducing environment in the western North Yellow Sea. DU1 (340-0 cm) was formed after 6.5 cal kyr BP. During this period, the study area remained in a shelf shallow sea environment characterized by relatively strong chemical hydrolysis and reducing conditions. The intensification of the Yellow Sea Warm Current and an increase in Yellow River sediment transported to the sea led to an obvious increase in sedimentation rate after 2.3 cal kyr BP.

Applications of trace element and isotope geochemistry in revealing origin and evolution of thermal spring water and ore deposit

Geochemistry is normally referred to as the study of Earth’s chemistry by exploring properties of materials and natural processes from deep beneath the Earth’s surface to the upper atmosphere, demonstrating the natural phenomena nowadays and discovering the history of nature. This study describes a subtopic of geochemistry: inorganic isotopes and trace elements, and discusses the application of the isotopes and trace elements in studies of geothermal spring water and ore deposit. The study of water samples in Hengjing, China was accomplished with the help of gas isotope analysis. The carbon isotope ratios and gas compositions indicate that the thermal waters are mostly sourced from meteoric and mantle sources in this area. The He isotope could evolute from mantle fluid, and CO2 is a product of the carbonate decomposition of rocks at high temperatures. The other study, conducted on the Zhaoxian ore deposit, revealed the origin and processes of formation of the different compositions of the ore. The magmatic-hydrothermal activity in this tectonically active area contributes much to the mineralization process of the ore, as shown by the analysis of trace elements of pyrite. The fluid inclusion He-Ar isotope shows that the ore was characterized by crust-mantle mixing with a little participation of meteoric water.

Sedimentary evolution and control factors of the Rizhao Canyons in the Zhongjiannan Basin, western South China Sea

Sedimentary evolution and control factors of the Rizhao Canyons in the Zhongjiannan Basin, western South China Sea

Electrochemical Recovery of Lithium-Ion Battery Materials from Molten Salts: Microstructural Characterisation Using X-Ray Imaging

Recycling spent Li-ion batteries (LiBs) guarantees the conservation of important metal resources by reducing demands on raw supply and offsetting the energy and environmental costs associated with its manufacture. However, selecting practical end of life solutions for battery waste management remains a challenge. Molten salts, on the other hand, are a well-established group of inorganic compounds and are understood to be one of the leading candidates in the recovery of valuable metals. They offer a much greener and simpler route to metal recovery by electrochemical means compared with the use of reducing agents for hydrometallurgical recovery [1]. Yet, the current mechanistic understanding of the electrochemical recovery of metals in molten salts needs to be improved.SEM, EDS and XRD are some of the most employed characterisation techniques used to reveal material composition and surface topography; however, they are known to expose the final product to air and moisture obscuring the results. X-ray computed tomography offers a non-destructive approach for 3D microstructure visualisation and subsequent quantification [2]. This technique can be used to study the morphological evolution of metal deposits from their oxide particles in a representative high-temperature medium to provide a wealth of information on the fundamentals of the electrochemical reduction process.Here, we demonstrate a study into the electrochemical deposition of recovered Co metal from lithium cobalt oxide, LiCoO2 in LiCl-KCl eutectic (LKE) which has been previously studied by the authors’ using a fluidised cathode arrangement [3]. This novel diagnostic approach has been applied to LiCoO2-LKE samples before and after electrolysis at 450 °C, yielding key insights into the morphological evolution of product formation. Different morphologies of recovered Co metal such as dendrite features and agglomerates have been captured and quantified. It has also been observed that CO/CO2 gas formation occurs in copious quantities at the anode surface leading to operational consequences such as the required overpotential needed to drive the reaction. For the first time, the application of X-ray imaging offers the ability to understand the role of process conditions and cell configurations to optimise a pyro-electrochemical reprocessing technology that can play a key role in sustainable battery recycling as well as refractory metal recovery.[1] B. Zhang, H. Xie, B. Lu, X. Chen, P. Xing, J. Qu, Q. Song, H. Yin, A Green Electrochemical Process to Recover Co and Li from Spent LiCoO2-Based Batteries in Molten Salts, ACS Sustain Chem Eng. 7 (2019) 13391–13399.[2] P.J. Withers, C. Bouman, S. Carmignato, V. Cnudde, D. Grimaldi, C.K. Hagen, E. Maire, M. Manley, A. du Plessis, S.R. Stock, X-ray computed tomography, Nature Reviews Methods Primers. 1 (2021) 1–21.[3] M. Mirza, R. Abdulaziz, W.C. Maskell, C. Tan, P.R. Shearing, D.J.L. Brett, Recovery of cobalt from lithium-ion batteries using fluidised cathode molten salt electrolysis, Electrochim Acta. 391 (2021) 138846.

Paleoenvironmental reconstruction of glaciomarine sediments in the Drygalski Basin of the western Ross Sea since the Last Glacial Maximum

The repeated growth and reduction of the ice sheet have controlled the striking variation of the continental shelf environment in the Ross Sea. Particularly, glaciomarine shelf sedimentation is closely related to the ice sheet dynamics and ice shelf development since the Last Glacial Maximum (LGM). Using the four gravity (and box) cores obtained from the northern Drygalski Basin in the western Ross Sea, multi-proxies including sediment properties, geochemical proxies, carbon isotopic values of organic matter, clay mineral compositions of fine-grained sediments, and diatom assemblage were analyzed with AMS 14C dating from bulk organic matters. Based on the core description, X-radiograph observation, and results of grain size distribution, the core sediments were classified into the seven sediment facies: clast-rich muddy diamicton, clast-rich sandy diamicton, massive mud, laminated mud, bioturbated mud, massive sandy mud, and bioturbated sandy mud. The association of these sediment facies defines the four lithologic units in terms of the depositional evolution. Lithologic unit 1 represents diamicton deposited proximal to the grounding line. When the ice sheet and ice shelf retreated since the LGM, the unsorted sediment mass was deposited proximal to the grounding line. Lithologic unit 2 consists of the massive mud deposited under the sub-ice shelf condition. During the ice sheet retreat, the fine-grained particles were transported by the meltwater plume to the sub-ice shelf floor. The biogenic materials were also transported from the seasonal open marine area to the sub-ice shelf by the currents. Lithologic unit 3 was composed of sandy mud and mud with abundant dropstones that might have been deposited at the calving line. As the calving line passed the Drygalski Basin, a large amount of the coarse fractions was deposited due to ice shelf breakup. The terrestrial sediments from the Victoria Land coast were transported from the grounding line of the remained local ice sheet, when the calving line passed the north side of Drygalski Ice Tongue. Lithologic unit 4 comprises the bioturbated mud and sandy mud that were deposited under the seasonal open marine condition. The biological productivity increased significantly during the late Holocene, while the terrestrial sedimentation decreased under seasonal open marine conditions. The diatom assemblage and δ13C values of sediment organic matter indicate the mid-Holocene warm climate with more sea ice melting. Since the LGM, the paleoenvironmental change and glaciomarine depositional evolution on the northern Drygalski Basin were closely linked with the ice sheet dynamics and ice shelf activity, in addition to the climate change during the Holocene.