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Antimony (Sb) is widely utilized in modern industries and classified as a critical mineral worldwide. China possesses the most abundant Sb mineral resources globally, with over 70% of proven reserves concentrated in southern China. However, due to excessive exploitation, the lifespan of Sb reserves is less than ten years. Therefore, the knowledge of Sb needs to be urgently strengthened. Here, the effectiveness of the geochemical block method to delineate the prospective areas of Sb deposits and determine the potential resource of Sb was studied, with geochemical data covering 2.3 million km2 across southern China. The statistical results showed that the median concentration of Sb in stream sediments (1.05 ppm) in southern China was 1.5 times that of whole China, indicating a significantly elevated background level of Sb in southern China. By setting the threshold value at 2.98 ppm, a total of nine distinct geochemical blocks were delineated. Remarkably, 85% and 76% of the large and medium Sb deposits were located within these geochemical blocks, respectively. Taking the block containing the Xikuangshan giant Sb deposit in Hunan Province as the model, the metallogenic coefficient of Sb is calculated to be 0.32%. The total potential Sb resources in southern China within a depth of 1000 m are estimated to be 21.939 million tons, which are primarily concentrated in the provinces of Hunan, Guangxi, Yunnan, and Guizhou. When the threshold value is set at 4.19 ppm, the predicted potential resources of Sb are 21.45 million tons in twelve blocks, which closely approximate 21.939 million tons. The estimated Sb resource in this study significantly surpasses the proven reserves. The periphery and deep areas of known Sb deposits still hold promising prospects for exploration. This study highlighted the effectiveness of employing the geochemical block method to estimate the potential resources of Sb and determined the ore-prospecting direction of Sb deposits. However, it is important to acknowledge and address the overestimation of predicted resources resulting from the high geological background. [ABSTRACT FROM AUTHOR]

Aqueous complexation has long been considered the only viable means of transporting gold to depositional sites in hydrothermal ore-forming systems. Here, we present direct evidence supporting an alternative hypothesis, namely, the transport of gold as colloidal particles. We observed nano-scale gold particles adsorbed on halloysite and micro-scale gold particles in altered rocks by TEM and SEM in the Shanggong orogenic gold deposit. Based on this evidence, we propose a feasible model for the origin of microscopic gold particles in alteration zones. In the early stage of ore-forming fluid, gold may migrate in the form of collaurum, which is maintained by supercritical CO2 and colloidal silica. Low salinity and high pressure are conducive to the stable migration of colloidal gold. When the physicochemical conditions change, some collaurum is precipitated and adsorbed by the clay minerals produced by hydrothermal alteration, and some collaurum undergoes growth and evolves into micro-submicrometer-sized gold particles. This study highlighted the significance of collaurum in the formation of orogenic gold deposits. [ABSTRACT FROM AUTHOR]

An analytical method to accurately determine trace levels of Se and Te is essential to meet the growing importance of these elements to Earth science research. Herein, an in‐house assembled photochemical vapour generation (PVG) unit, instead of normal sample nebulisation, with inductively coupled plasma‐mass spectrometry (ICP‐MS), was developed for the detection of Se and Te in geological samples. The major parameters that might potentially influence the PVG efficiencies of Se(IV) and Te(IV) were investigated. The unit could fully generate volatile species under 30 s of ultraviolet irradiation in the presence of 15% v/v formic acid, 15% v/v acetic acid and 50 mg l‐1 of Co2+. Under optimised conditions, the limit of detections (LODs, 3s, n = 11) of the proposed method were 0.5 ng l‐1 for Se and 0.6 ng l‐1 for Te. The RSDs of Se and Te were 2.0% and 2.3% (1 μg l‐1, n = 7), respectively. Interference experiments showed that Fe, Ti, V and Cu have certain negative effects, so the standard addition method was used for real sample analysis. Measurement results for eleven CRMs, including soils (GSS‐4, GSS‐7), sediments (GSD‐9, GSD‐10) and rocks (GSR‐1, GSR‐2, GSR‐3, GSR‐5, AGV‐2, GSP‐2 and W‐2a), were consistent with literature values, and showed better precision, indicating the feasibility of the proposed method for determination of trace Se and Te in geological samples. [ABSTRACT FROM AUTHOR]

Malaysia's commitment to ecological quality is evident in its agendas for achieving a sustainable environment by 2030. However, hindrances like challenges towards energy transition efforts, stable political institutions, unclean economic globalization practices, and transiting to a complex economy could potentially delay the nation's attainment of its environmental goals. Against this backdrop, the current study focuses on examining the roles of political risk, economic globalization, energy transition, and economic complexity on ecological sustainability in Malaysia. In contrast to previous studies, this study innovatively incorporates a dummy variable to account for potential structural breaks that may occur during the study period. Furthermore, this study used an innovative environmental proxy which incorporates both the demand and supply aspect of the environment during computation. Using the time series data from 1984 to 2018 and employed the ARDL estimator method, the empirical results indicate that economic globalization is associated with ecological deterioration in Malaysia in the long run. On the other hand, economic complexity, political stability, and energy transition are shown to promote ecological sustainability in Malaysia in the long run. Moreover, the bootstrap time varying causality method demonstrates that each of the regressors has the capacity to predict the load capacity factor during distinct sub-periods. [ABSTRACT FROM AUTHOR]

Ion adsorption-type rare earth element (REE) ore deposits in South China are a major source of heavy rare earth elements (HREE) around the world, which are of considerable economic and strategic significance. In these ores, REE is enriched in the clay minerals, specifically kaolinite and halloysite, which are derived from their parent granitoid by the weathering process. However, the mechanisms of supergene REE mineralization remain unclear. We investigated the nature and origin of supergene REE mineralization, based on a nanoscale study of a typical REE-mineralized granite regolith profile (ΣREEmax = 1201 ppm) in the Dazhou super-large, ion adsorption-type REE deposit, Guangxi Province, South China. Bulk mineralogical and geochemical analyses, coupled with novel nano-characterization techniques [i.e., hollow fiber flow field-flow fractionation inductively coupled plasma-mass spectrometry (HF5-ICP-MS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM)], were used to determine the nature of the nano-minerals and nanoparticles in the regolith samples. X-ray diffraction and SEM-EDS analyses revealed that ion-adsorption clay minerals are dominated by platy-shaped kaolinite and rod-like halloysite (10 and 7 Å) within the regolith. The average clay mineral contents decreased from 38 to 15% from the fully weathered horizon to the semi-weathered horizon, whereas the proportion of halloysite increased in the clay mineral fraction in the deep horizons. The REE-bearing nanoparticles consist predominantly of macromolecules of organic matter (2–5 nm) and clay minerals (5–40 and 40–80 nm) according to the HF5-ICP-MS analysis. There is a close association between REE and Al contents in particles with sizes of 5–40 nm in the semi-weathered horizons and 40–80 nm in the highly weathered horizons, which indicates that nanoscale clay minerals (halloysite and kaolinite, respectively) are important REE carriers. In addition, nanoscale secondary REE mineral phases, including oxide, silicate, and phosphate, were identified by the SEM and TEM observations. These phases are typically adsorbed onto the surfaces of clay minerals, specifically rod-like halloysite, but have different occurrences in the regolith profile. Cesium-oxide (cerianite) and Ce-silicate (cerite) occur mainly in the upper horizon of the regolith profile, whereas low-crystallinity REE phosphates [rhabdophane-(La)] occur mainly in the lower horizon of the profile. Our results indicate that nano-minerals and nanoparticles affect REE enrichment and fractionation during granite weathering. Migration and accumulation of REE-bearing nano-minerals were caused by leaching and neoformation of REE-bearing nano-minerals during secondary precipitation. These processes contribute to the formation of supergene REE mineralization in granite regolith. [ABSTRACT FROM AUTHOR]