Deposition Conditions Research Articles

Electrophoretic deposition of carbon-ionomer layers on proton conducting membranes.

Synthetic and natural carbons are widely used as carrier for electrodes in electrochemical applications. They need to have a controlled morphology in order to facilitate mass and charge transport, so the process of film formation is of uttermost importance. Here we show, how carbons (after proper preconditioning) can be codeposited with an ionomer by electrophoretic deposition, a method that does allow full control of deposition conditions during the process. In view of potential applications, we focus on the direct deposition on proton-conducting membranes. Ionomers and membranes applied are based on established per-fluorinated polyethylene with SO3H-terminated side chains (PFSA). Conditions for reproducible deposition are reported in terms of optimal charge on the carbon particles, field strength in the deposition cell and necessary deposition times for a given film thickness. Additionally, a horizontal cell arrangement is suggested to avoid gravitational effects.

The Mechanism of Aluminum Deposition and Dendrite Growth on a Copper Substrate in Anode-Free Aluminum Batteries.

Given the critical demand for batteries with a high energy density and the global scarcity of lithium, anode-free aluminum batteries (AFABs) have attracted significant attention. AFABs utilize collectors instead of traditional anode metal foils, eliminating the need for anode materials and significantly enhancing the energy density of the batteries. However, the proliferation of aluminum dendrites might cause safety risks and reduce Coulombic efficiency, possibly impeding commercialization. This study employs molecular dynamics (MD) simulations to explore the deposition mechanisms of aluminum (Al) on copper (Cu) collectors and the dynamics of aluminum dendrite growth under nonhomogeneous deposition conditions. The results indicate that the surface properties of the Cu substrate significantly affect aluminum deposition, leading to more homogeneous and amorphous deposition on Cu(110) surfaces. However, the FCC structure of Al atoms on the Cu(111) surfaces exhibited the largest number. Strategically increasing the temperature and pressure can effectively prevent the formation of aluminum dendrites. The results are helpful for enhancing the battery cycle stability and the application of novel AFABs.

Microscopic examination of rf-cavity-quality niobium films through local nonlinear microwave response

The performance of superconducting radio-frequency (SRF) cavities is sometimes limited by local defects. To investigate the rf properties of these local defects, especially those that nucleate rf magnetic vortices, a near-field magnetic microwave microscope is employed. Local third-harmonic response (P3f) and its temperature dependence and rf power dependence are measured for one Nb/Cu film grown by direct current magnetron sputtering (DCMS) and six Nb/Cu films grown by high-power impulse magnetron sputtering (HiPIMS) with systematic variation of deposition conditions. Five out of the six HiPIMS Nb/Cu films show a strong third-harmonic response that is likely coming from rf vortex nucleation due to a low-Tc surface defect with a transition temperature between 6.3 and 6.8 K, suggesting that this defect is a generic feature of air-exposed HiPIMS Nb/Cu films. A phenomenological model of surface-defect grain boundaries hosting a low-Tc impurity phase is introduced and studied with time-dependent Ginzburg-Landau (TDGL) simulations of probe-sample interaction to better understand the measured third-harmonic response. The simulation results show that the third-harmonic response of rf vortex nucleation caused by surface defects exhibits the same general features as the data, including peaks in third-harmonic response with temperature, and their shift and broadening with higher microwave amplitude. We find that the parameters of the phenomenological model (the density of surface defects that nucleate rf vortices and the depth an rf vortex travels through these surface defects) vary systematically with film deposition conditions. From the point of view of these two properties, the Nb/Cu film that is most effective at reducing the nucleation of rf vortices associated with surface defects can be identified. Published by the American Physical Society 2024

Ichnological record in gateways and other high-energy deepwater environments: a palaeo- and neoichnological approach

The evolution of gateways determines variations in palaeoenvironmental (ecological and depositional) conditions affecting tracemaker communities, and hence biogenic structures. With respect to palaeogateways, bottom currents and associated deposits (i.e. contourites) may be approached through trace-fossil studies. Ichnological analysis – individual ichnotaxa and changes in ichnofacies – of Late Miocene contourites and associated facies from the Rifian Corridor palaeogateway (Morocco) reveals a major impact of food supply, flow velocity, seafloor heterogeneity and hydrodynamic energy. The fact that Eocene to middle Miocene deep-marine deposits, mainly contourites, from the nearby Indian palaeogateway (Cyprus) show ichnofacies replacement is evidence of increased bottom-current flow velocity associated with sea-level variations. Moreover, ichnofabric changes reflect pelagic, gravitational and bottom-current processes that simultaneously influence sedimentation. Changes in the trace-fossil composition of both areas, and in the shape of burrows, reflect intermittent bottom-current processes that governed contourite deposition. Neoichnological studies complement and validate the trace-fossil record of high-energy deep-sea environments that can occur in palaeogateways. Modern traces ( lebensspuren ) observed on the seafloor show variable features (e.g. diversity, density, morphology) depending on the type of disturbance that high-energy conditions exert on the trace-making benthic fauna. Parameters such as substrate consistency, nutrient availability/distribution and the duration and intensity of energetic events play a major role in determining lebensspuren features. We conclude that an integrative palaeo- and neoichnological approach is a powerful tool when used to improve our knowledge of benthic ecosystems in high-energy deep-sea environments such as gateways.

Machine Learning-Enhanced Fabrication of Three-Dimensional Co-Pt Microstructures via Localized Electrochemical Deposition

This paper presents a novel method for fabricating three-dimensional (3D) microstructures of cobalt–platinum (Co-Pt) permanent magnets using a localized electrochemical deposition (LECD) technique. The method involves the use of an electrolyte and a micro-nozzle to control the deposition process. However, traditional methods face significant challenges in controlling the thickness and uniformity of deposition layers, particularly in the manufacturing of magnetic materials. To address these challenges, this paper proposes a method that integrates machine learning algorithms to optimize the electrochemical deposition parameters, achieving a Co:Pt atomic ratio of 50:50. This optimized ratio is crucial for enhancing the material’s magnetic properties. The Co-Pt microstructures fabricated exhibit high coercivity and remanence magnetization comparable to those of bulk Co-Pt magnets. Our machine learning framework provides a robust approach for optimizing complex material synthesis processes, enhancing control over deposition conditions, and achieving superior material properties. This method opens up new possibilities for the fabrication of 3D microstructures with complex shapes and structures, which could be useful in a variety of applications, including micro-electromechanical systems (MEMSs), micro-robots, and data storage devices.

Corrigendum to: Thermodynamic analysis of ethanol steam reforming using Gibbs energy minimization method: A detailed study of the conditions of carbon deposition [International Journal of Hydrogen Energy 34 (2009) 4321–4330]

Corrigendum to: Thermodynamic analysis of ethanol steam reforming using Gibbs energy minimization method: A detailed study of the conditions of carbon deposition [International Journal of Hydrogen Energy 34 (2009) 4321–4330]

Carbon, iron and sulfur records of lacustrine paleo-environments during the middle Eocene in eastern China

It is widely recognized that anoxic conditions facilitate the preservation of organic carbon in marine sediments. However, the specific geological factors that lead to the development of such conditions in paleo-lakes are less well understood. Owing to their smaller size, paleolakes could experience more frequent and stronger changes in geochemical conditions than oceans. Such changes, such as volcanism, hydrothermal fluids, or ocean transgressions, can also strongly affect the lacustrine organic carbon burial thereby complicating sediment diagenesis record. Here, we used total organic carbon content (TOC), organic carbon isotope (δ13Corg), iron speciation, and pyrite sulfur isotope (δ34Spy) data to establish relationships between organic carbon preservation and anoxic conditions in fine-grained sediments from the middle Eocene lacustrine depositional environments from the Shahejie Formation of the Jiyang Depression, Bohai Bay Basin, eastern China. The results reveal TOC between 1 % and 10 %, highly-reactive iron to total iron ratios >0.38, and most TOC to total sulfur ratios exceeding 2. These data indicate that the organic-rich shales of the Shahejie Formation were formed as a result of high primary productivity during the warm and humid middle Eocene period, coupled with the efficient preservation of organic matter in anoxic bottom waters. Negative δ13Corg and δ34Spy excursions recorded in the Shahejie Formation indicate water column conditions to have been influenced by transient volcanic eruptions. Positive δ13Corg and negative δ34Spy excursions may have been caused by hydrothermal fluids input whereas δ34Spy values approaching 20 ‰ suggest frequent marine transgressions. In particular, despite potential inputs of S into the paleolake by volcanism, hydrothermal fluids, or marine transgressions, bacterial sulfate reduction efficiently depleted the sulfate pool to have created ferruginous geochemistry water conditions for the effective preservation of organic carbon in sediments. Our results establish a direct link between lacustrine shale geochemical signatures and geological phenomena that impact its sedimentation.

Optimization of LPCVD Deposition Conditions of Silicon-Rich Silicon Nitride to Obtain Suitable Optical Properties for Photoluminescent Coating

Silicon nitride is a commonly used material for ceramic applications and in the fabrication processes of integrated circuits (ICs). It has also increased in interest from the scientific community for use as a functional coating due to its physical, mechanical, electrical, and optoelectronic properties. In particular, silicon-rich silicon nitride (SRSN) has been considered in the photovoltaic industry as a down-conversion film for solar cells. In this work, SRSN films have been obtained by the Low-Pressure Chemical Vapor Deposition (LPCVD) technique at low to moderate deposition temperatures with a variation in the precursor gas pressure ratio. The SRSN films showed a wide photoluminescence (PL) in the visible region (without a high-deposition temperature or annealing process) and suitable optical properties (refractive index and absorption in the UV) to be used as photoluminescent coating on silicon solar cells. The absence of high-deposition temperatures could preserve the original structure of silicon solar cells, once the SRSN layer was applied. In addition, control of the reactive gas pressure ratio and deposition temperature showed an influence on the refractive index, the surface roughness, and the PL emission.

Assessment of recent lake sediment conditions in the conterminous U.S.

This study provides the largest sediment quality assessment of lakes in the conterminous United States (U.S.). A variety of lakes (n = 1005) were selected based on the randomized, probabilistic sampling design of the broader 2017 National Lakes Assessment study. Surficial sediment samples (0–5 cm) were collected at one representative site (generally the deepest point) for each lake (n = 969). The samples were analyzed for 16 metal(loid)s, 25 polycyclic aromatic hydrocarbons (PAHs), 53 polychlorinated biphenyl (PCB) congeners, 27 legacy pesticides and metabolites, total organic carbon, and grain size. Metal(loid)s and PAHs were widely distributed due to natural and potential anthropogenic sources, with regional variations observed for lakes in the nine ecoregions encompassing the U.S. Most sites did not have detectable PCB congeners or legacy pesticides. An integrative chemical index of mean probable effect concentration quotients, composed of seven metal(loid)s and ƩPAH13, was used to assess sediment quality for the estimated population of 224,916 lakes in the conterminous U.S. Nationally, 26.5 % (CI of 20–33 %) of lakes were in good condition (corresponding to predicted low incidences of toxicity to benthic organisms), 69.3 % (CI of 63–76 %) of lakes were in fair condition, and 1.8 % (CI of 0.6–3 %) of lakes were in poor condition (corresponding to predicted high incidences of sediment toxicity). Unweighted metal(loid) and ƩPAH13 concentrations were compared to lake, watershed, and land use data. Deeper lakes were significantly more contaminated (or naturally enriched) with As, Cd, Cu, Pb, Hg, Zn, and ƩPAH13 than shallow lakes. Lakes at lower elevation were also associated with more contamination (or natural enrichment) of As, Cr, Pb, Hg, Ni, Zn, and ƩPAH13 than higher elevation lakes. Greater contamination was associated with watersheds containing larger percentages of developed land. This study demonstrates an approach which can be used by others to assess sediment quality in their jurisdictions.

Key Sputtering Parameters for Precursor In2O3 Films to Achieve High Carrier Mobility.

Owing to their extremely high carrier mobility (μ) of >100 cm2/(V s) and suitable low carrier concentrations, transparent conducting films of solid-phase crystallized H-doped In2O3 (spc-IO:H) exhibit high conductivity with high optical transparency over a broad frequency range. These properties can be attributed to solid-phase crystallization of the amorphous precursor film. Therefore, the development of high-quality spc-IO:H films requires the deposition conditions of the precursor films to be optimized. This study systematically investigates the effects of three key sputtering parameters, namely, water vapor partial pressure (PH2O), radio frequency magnetron sputtering power (PRF), and flow ratio of O2 to total sputter gas (fO2) on the crystallographic texture evolution of spc-IO:H films during solid-phase crystallization. In addition, the carrier transport in the resulting films is examined. PH2O, PRF, and fO2 are found to be indispensable for producing high-mobility (>100 cm2/(V s)) spc-IO:H films. Furthermore, it is found that introducing a small amount of PH2O during deposition, a lower PRF, and a suitable fO2 facilitates the formation of precursor films having a lower crystallite density. Moreover, after annealing at a temperature of 200 °C, the IO:H precursor films with a lower crystallite density are found to have larger crystal grains. However, the μ values of the postannealed IO:H films are mainly correlated with the stoichiometric deviation.

Innovative geological–geotechnical zoning framework for urban planning: Wuhan’s experience

Traditional methods for understanding geological conditions, such as borehole drilling and on-site tests, are often costly and impractical for extensive urban areas like Wuhan’s Main Urban Area. This study introduces an innovative geological–geotechnical zoning framework that utilizes limited data to overcome these challenges, essential for urban planning, underground space development, and construction design. We began by dividing the study area into four primary geological units based on geomorphological characteristics, using a novel method validated at four metro stations. Our approach incorporated data from 1544 geological boreholes to compile a comprehensive database, from which six typical stratigraphic profiles for each unit were identified. These profiles facilitated the estimation of potential layers and their corresponding geotechnical parameters, and the identification of subsurface hazards. The study resulted in a detailed engineering geological zoning divided into nine secondary units. Our analysis not only demonstrates the effectiveness of the proposed criteria for geomorphological units in achieving more accurate and quantifiable outcomes but also shows the framework’s suitability for regions with complex sedimentary conditions. The resultant engineering geological zoning enhances understanding of geological risks, providing a foundation for safer and more sustainable urban development.

The constraints of sedimentary environment on the evolution of bauxite reservoir characteristics within the benxi formation in the Linxing area, Ordos Basin, China

AbstractThe breakthrough of bauxite natural gas in the Taiyuan Formation in the Longdong area of the Ordos Basin makes bauxite natural gas gradually become a new exploration direction. However, the complex sedimentary conditions and diverse developmental strata of the Linxing region present difficulties for the exploration of bauxite gas. In this research, samples of bauxite cores from significant drilling sections in the Linxing area were obtained for comprehensive geochemical, mineralogical, and pore structure analysis. This study investigates the impact of sedimentary environments on the physical properties of bauxite reservoirs within the Benxi Formation, focusing on lithofacies categorization, mineral composition, and pore structure. This study established a lithofacies categorization system that iron minerals, aluminum minerals + titanium minerals, clay minerals as three end‐member components. The study identified four lithofacies types: pure bauxite, clayey bauxite, mixed bauxite, and bauxite mudstone. According to geochemical analysis, the bauxite rock in the study area is deposited in a semi‐enclosed bay with terrestrial freshwater input. The physical properties of bauxite reservoir in the study area are relatively poor, among which the physical properties of bauxite reservoir are the best. Authigenic minerals like pyrite are often filled in dissolution pores. The constraint of sedimentary environment on bauxite reservoir is mainly manifested as the influence on the formation of diaspore mineral framework, and its acidity and alkalinity are very important for the formation of diaspore. Hence, diaspore commonly forms in the shallow lake environments characterized by pure bauxite rock, exhibiting favorable reservoir conditions. This research examines the impact of mineral composition on bauxite reservoirs through the lens of lithofacies and sedimentary environments. The variations in bauxite rock reservoirs across distinct sedimentary environments have been elucidated. It provides a new guidance for the exploration of natural gas in Benxi Formation bauxite in Ordos Basin.

Development of the Ge-MDST instrument structure with an induced p-type channel

The conditions for the growth of n-type Ge conduction layers by the HW CVD method with the parameters required to create a Ge-TIR transistor with an induced p-type channel are determined. The conditions of deposition by electron beam deposition and subsequent annealing of layers of a high-k dielectric ZrO2:Y2O3 are optimized, allowing to achieve a leakage current of 5 × 10–6 A/cm2. For the developed instrument structure, some parameters of the Ge-TIR transistor were calculated, such as the channel length, the maximum voltage between the drain and the source, and the breakdown voltage.

Assessment of Water Status, Bottom Sediments, Macrophytes in the Light of Index Analysis and Geochemical Parameters of Selected Dam Reservoirs of Kielce Upland (Poland)

Concentrations of trace elements such as Cr, Zn, Cd, Co, Mn, Cu, Ni, Pb, and Fe were investigated in water, bottom sediments, and macrophytes (Phragmites australis and Typha latifolia L.) collected from the Borków, Wilków, and Rejów water reservoirs in the Kielce Upland (Poland). The main objective of this study was to investigate the condition of water, bottom sediments, and macrophytes in selected three sedimentary basins of the Kielce Upland and to identify natural and anthropogenic factors influencing this condition. The secondary objectives were (i) to determine the contents of trace metals in water, bottom sediments, and macrophytes, (ii) to assess the quality of abiotic and biotic elements of the ecosystem based on selected criteria, (iii) to compare reservoirs in terms of pollution, and (iv) to determine the ability of macrophytes to be used as a bioindicator of water/sediment pollution. Field tests were conducted in 2021. The trace metals in water were determined by ETAAS (Cr, Cd, Mn, Cu, Ni, Pb) and FAAS (Zn), and spectrophotometry method (Fe). The trace metals in sediments and macrophytes, including Cr, Zn, Cd, Co, Mn, Cu, Ni, Pb, and Fe, were detected using ICP-OES method. Contamination of bottom sediments with potentially toxic metals was determined based on the geo-accumulation index (Igeo), contamination factor (CF), and pollutant load index (PLI). Statistical analyses were performed using the Statistica PL 13.1. The analyses showed that the accumulation of trace elements in the surface layer of the reservoir sediments increases as follows: in Borków, Cd < Co < Ni < Cu < Pb < Cr < Zn < Mn < Fe; in Wilków, Cd < Co < Cu < Ni < Pb < Cr < Zn < Mn < Fe; and in Rejow, Cd < Co = Cu = Ni = Pb < Zn < Cr < Mn < Fe. It was shown that the average distribution of metals in the bottom sediments of the studied reservoirs was as follows: Borków > Wilków > Rejów. Research has shown that the degree of trace metal accumulation increases as follows: water < sediments < macrophytes (except Pb from the reservoir in Borków).

Enhanced optoelectronic characteristics of La-doped ZnO and its compatibility with Cs-doped MAPbI3 perovskite absorber material

Abstract The present study investigates the structural, electrical and optical characteristics of pristine and lanthanum (La)-doped zinc oxide electron transport layers (ETLs) fabricated by the sol gel method and their compatibility with Cs0.10MA0.90Pb(I0.9Br0.10)3 absorber layer for perovskite solar cells. All the ETLs were deposited under same deposition conditions, with the only difference in La percentage in the precursor solutions, ranging from 0 to 6%. X-ray diffraction (XRD) analysis demonstrated the presence of crystalline ZnO thin films and the absence of any impurity phases after La-doping. The calculated crystallite size, determined using Scherrer’s equation, increased from 11.13 to 21.76 nm after the introduction of dopant. The doping with 4% La led to the decrease in the optical bandgap from 3.32 eV of pristine ZnO to 3.23 eV. SEM analysis revealed better morphology of perovskite/4% La:ZnO specimen, which facilitated the absorbance and reduced the charge carrier recombination. It also exhibited superior resilience towards moisture and humidity which will eventually contribute to the development of more stable and efficient planar perovskite solar cells (PCSs).

Lithology and sedimentation conditions of the latest Cretaceous of the Klementyeva Mountain section (Eastern Crimea)

Overall study of the boundary Maastrichtian–Danian deposits of Klementyeva Mountain section (Eastern Crimea) was carried out. The lithological characteristics of carbonate, carbonate-argillaceous and clastic rocks were described in detail, the dynamic of changes in foraminifera assemblages was analyzed. For the first time, geochemical and isotopic data were obtained for this section. The stratigraphic complement of the Upper Maastrichtian and Lower Danian has been specified. Late Campanian – Early Maastrichtian age of the underlying deposits was established, for the first time. The Klementyevskaya Formation was formed in deep-sea pelagic paleoenvironments on the submerged part of the outer shelf, and the overlying Lower Danian sediments were formed in shallow waters of the inner shelf with terrigenous sedimentation and high hydrodynamic activity.

Examining the effect of post-depositional processes on the preservation and identification of stone tool residues from temperate environments: An experimental approach.

Studying taphonomy is crucial for understanding how post-depositional processes impact archaeological remains. This knowledge is pivotal for accurately interpreting the archaeological record. Although taphonomy has a long tradition in archaeology, it is less developed in the analysis of stone tool residues compared to other subdisciplines. To address this gap, our study aims to further develop our understanding of the preservation potential of stone tool residues in temperate environments through actualist experiments. To achieve this, we develop a multidimensional experimental program that features the first biweekly monitoring of weathering processes on residues over a one-year cycle, aiming to understand the short-term effects of weathering immediately after tool discard. Additionally, the program involves the study of longer-term burial and weathering visual effects on different residue types within various previously unexplored depositional environments. This approach allows us to observe the visual effects of both weathering and burial processes and to improve our understanding of the different mechanisms involved in the diagenesis of stone tool residues. While known factors such as microbial activity and soil acidity play a primary role in residue decay, specific stone tool-related factors also prove important, underscoring the need to develop further a specific branch of taphonomy related to stone tool residues. Moreover, our results show that certain residue types may survive within these environments that are often considered as being hostile. A residue analysis of stone tools from temperate contexts may thus contribute unique data that can improve our understanding of past human behaviour. Future research with more diverse residue types and depositional conditions will permit further refinement of our understanding of how taphonomy affects residue preservation and enhance the reliability of residue identifications. As such, stone tool residue analysis will become firmly rooted within broader functional approaches to address how humans use stone tools and how this affects stone tool variability.

Hydrogen Evolution Reaction of Electrodeposited Ni-W Films in Acidic Medium and Performance Optimization Using Machine Learning.

Ni-W alloy films were electrodeposited from a gluconate aqueous bath at pH = 5.0, at varying current densities and temperatures. While there is little to no difference in composition, i.e., all films possess ~12 at.% W, their activity at hydrogen evolution reaction (HER) in acidic medium is greatly influenced by differences in surface morphology. The kinetics of HER in 0.5 M H2SO4 indicates that the best performing film was obtained at a current density of -4.8 mA/cm2 and 50 ºC. The Tafel slopes (b) and the overpotentials at a geometric current density of -10 mA/cm2 (η10) obtained for 200 cycles of linear sweep voltammetry (LSV) from a set of films deposited using different parameters were fed into a machine learning algorithm to predict optimum deposition conditions to minimize b, η10, and the degradation of samples over time. The optimum deposition conditions predicted by the machine learning model led to the electrodeposition of Ni-W films with superior performance, exhibiting b of 33-45 mV/dec and and η10 of 0.09-0.10 V vs. RHE after 200 LSVs.

Identification of prospective oil-bearing areas in the peripheral parts of productive horizons U-12 and U-13 of the Zhetybai field

Background: To date, a comprehensive range of scientific, geological exploration, and appraisal work has been conducted at the Zhetybai field. The overall structural map of the field has been relatively well established. However, several critical issues remain insufficiently studied or entirely unexplored. Based on the results of seismic exploration (3D common depth point method) and additional appraisal work, peripheral (edge) zones of the field structure have been identified, including its cross-faults, as well as transverse flexures and longitudinal faults on the southern wing of the structure, which require further investigation. Aim: To further study the field structure, identify new potential hydrocarbon areas in the peripheral parts of the field, and assess the oil potential of the U-12 and U-13 horizons in the Zhetybai field. Materials and methods: This study involved a qualitative assessment of the informativeness of seismic attributes, analysis of reflection geometry (configuration), dynamic amplitude parameters, continuity of frequency, and other indicators. The analysis of reflection characteristics, in conjunction with all available data, primarily geophysical survey data, allowed for hypothesizing sedimentary conditions and obtaining acceptable lithological assessments. Results: The evaluation wells J-1, J-2, and J-3, drilled in 2023-2024 in the peripheral parts beyond the approved boundary of hydrocarbon-bearing horizons U-12 and U-13, yielded positive results. The productivity of the new reservoir was also confirmed by newly drilled production wells 5333, 5652, and 5367. Conclusion: To further study the structure of the Zhetybai field and identify new potential hydrocarbon-bearing areas in the peripheral parts, as well as structural uplifts and sandstone bodies of horizons U-12 and U-13, evaluation wells J-1, J-2, and J-3 were drilled. The detailed identification of sandstone bodies allows for the prediction of prospective areas not covered by drilling. The positive results from drilling evaluation wells have refined the geological structure of horizons U-12 and U-13 and confirmed the productivity of the peripheral parts of the reservoirs.

Geochronology and petrogenesis of Early Mesozoic Rb-mineralized granitic rocks from the Liuzhangshan Rb, West Qinling Orogen Belt, China

ABSTRACT The newly discovered Liuzhangshan (LZS) Rb deposit is a large granite-type deposit in the West Qinling Orogenic Belt (WQOB), spatially associated with biotite monzogranite. Previous research has focused on the geological characteristics and metallogenic conditions of the LZS Rb deposit; however, its geochronology and petrogenesis remain unclear. In this study, monazite U-Pb dating of biotite monzogranite in the LZS deposit yielded a U-Pb age of 200.8 ± 0.9 Ma via laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Combined with the age of magmatic rocks in the WQOB, we propose a potential mineralization event related to Rb around 200 Ma in the WQOB. The biotite monzogranite belongs to weakly peraluminous, high-K calc-alkaline serious, containing high SiO2, Na2O, K2O, and low FeO, MgO, CaO, and P2O5. Compared with primitive mantle and relatively unfractionated granodiorites found in the WQOB, the biotite monzogranite enriched in Rb, Th, U, and Pb, deleted in Ba, Sr, and Ti, and showed negative Eu anomalies, a high Rb/Sr ratio, and a low K/Rb ratio, an ∑REE of 31.3 ppm, an LREE/HREE ratio of 6.48, a LaN/YbN ratio of 2.59, an Mg# of 4.15, and a crystallization temperature of 760°C, the biotite monzogranite also had a high differentiation index (DI = 98.2), apparent tetrad effect (TE 1,3 = 1.12 ~ 1.15), characteristic of highly fractionated I-type granite. Monzoite from the biotite monzogranite in the LZS deposit has negative εNd(t) values ranging from −12.45 to −11.17, and TDM1 of 1569 ~ 2018 Ma, indicating that the LZS biotite monzogranite originated from the partial melting of a Mesoproterozoic ancient basement material, with a minor contribution from mantle-derived melts. Highly differentiated, low Sr and Yb contents, Sr/Yb ratios, and low crystallization temperature magma facilitated the enrichment of Rb.