Guangzhou Institute of Geochemistry
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Grid Model of Energy Consumption Using Random Forest by Integrating Data on the Nighttime Light, Population, and Urban Impervious Surface (2000-2020) in the Guangdong-Hong Kong-Macau Greater Bay Area
No full textEnergy consumption is an important indicator for measuring economic development and is closely related to the atmospheric environment. As a demonstration zone for China's high-quality development, the Guangdong-Hong Kong-Macao Greater Bay Area imposes higher requirements on ecological environment and sustainable development. Therefore, accurate data on energy consumption is crucial for high-quality green development. However, the statistical data on local energy consumption in China is insufficient, and the lack of data is severe, which hinders the analysis of energy consumption at the metropolitan level and the precise implementation of energy policies. Nighttime light data have been widely used in the inversion of energy consumption, but they can only reflect socio-economic activities at night with certain limitations. In this study, a random forest model was developed to estimate metropolitan-level energy consumption in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2020 based on nighttime light data, population data, and urban impervious surface data. The estimation results show that our model shows good performance with an R2 greater than 0.9783 and MAPE less than 9%. A long time series dataset from 2000 to 2020 on energy consumption distribution at a resolution of 500 m in the Guangdong-Hong Kong-Macao Greater Bay Area was built using our model with a top-down weight allocation method. The spatial and temporal dynamics of energy consumption in the Greater Bay Area were assessed at both the metropolitan and grid levels. The results show a significant increase in energy consumption in the Greater Bay Area with a clear clustering, and approximately 90% of energy consumption is concentrated in 22% of the area. This study established an energy consumption estimation model that comprehensively considers population, urban distribution, and nighttime light data, which effectively solves the problem of missing statistical data and accurately reflects the spatial distribution of energy consumption of the whole Bay Area. This study provides a reference for spatial pattern analysis and refined urban management and energy allocation for regions lacking statistical data on energy consumption
A shallow ( < 100 km) ilmenite-bearing pyroxenitic source for young lunar volcanism
No full textThe lunar magma ocean (LMO) hypothesis predicts that the uppermost mantle (-60-100 km) is composed of ilmenite-bearing cumulate (IBC), which may have sunk deeply due to gravitational instability. However, the extent to which this process restructured the lunar mantle and influenced mare volcanism remains unclear. Here, we approach this issue by examining pyroxenes in Chang'E-5 (CE5) basalts and petrological modeling. We show that the low Mg# and negative anomalies in Ti and Ta of CE5 basalts cannot be produced by extensive fractionation of peridotite-derived low-Ti basalts, but were most likely formed through partial melting of a shallow (< 100 km) IBC pyroxenite source. This model is also applicable to the -3.0 Ga lunar basaltic meteorites. The increasing involvement of IBC sources in young lunar magmas, also revealed by the remote-sensing data, implies an inefficient gravitational restructuring process during the late LMO stage and provides new insights into the thermochemical state of the lunar interior
Multiple mineralization events in the Central Borneo metallogenic belt, Indonesia: Insights from the Beruang Kanan orefield
No full textThe Beruang Kanan is an important polymetallic orefield in Indonesia and is the first reported example of coexisting Cretaceous and Miocene mineralization on the island of Borneo. This study presents new U-Pb-Hf isotope and pyrite chemistry data to characterize the tectono-magmatic events tied to the ore formation at Beruang Kanan, and to establish the geochronological framework for gold and base metal mineralization across the Central Borneo region. Base metal mineralization (ca. 102-105 Ma) was closely linked to the emplacement of Sepauk tonalite (ca. 120-108 Ma) and its associated volcanism. Gold mineralization (ca. 13.09-9.18 Ma) was associated with the emplacement of Sintang intrusion (ca. 13.94-9.33 Ma). Pyrite grains from the Cretaceous Menunuk volcanics has lower gold content than those from the Miocene Malasan volcanics, reflecting the multiphase nature of the mineralization at Beruang Kanan. The Cretaceous and Miocene magmatism may have mainly formed the base-metal and gold-silver mineralization, respectively. Central Bornean ore deposits from both metallogenic epochs are attributed to calc-alkaline subduction-related magmatism. The metallogenic potential of intra-plate volcanic rocks and granitoids formed in the Jurassic and Plio-Pleistocene period has yet to be explored
Parameterized atmospheric oxidation capacity during summer at an urban site in Taiyuan and implications for O<sub>3</sub> pollution control
No full textIn recent years, summer ozone pollution shows a significant upward trend in many cities of China, affecting human health and ecosystems. The atmospheric oxidation capacity (AOC) is the core driving force for converting primary pollutants into secondary pollutants. In order to better understand the characteristics of AOC in summer, the comprehensive observation of VOCs (including OVOCs) was conducted at an urban site in Taiyuan from July 20 to August 3, 2020. The parameterized analysis of AOC and R-OH was carried out by combining with the simulated photolysis rates (J(O1D), J(NO2) and J(NO3)). The results showed that the mean value of MDA8 O-3, AOC and R-OH were 84.2 ppbv, 2.4 x 10(7) molecules cm(-3) s(-1) and 28.3 s(-1), respectively. The major reductants of AOC were CO (37.6%), isoprene (21.7%) and formaldehyde (16.8%). Diurnal variations of AOC showed a peak at noon, the major oxidants for AOC were OH (97.7%) and O-3 (78.7%) during the daytime and nighttime, respectively. The mean value of MDA8 O-3, AOC and VOCs-AOC during the pollution period (MDA8 O-3 > 75 ppbv) were 33.0%, 45.0% and 59.3% higher than the non-pollution period, respectively. The OH reactivity ratio of NOx and VOCs indicated that O-3 formation occurred under a VOC-limited regime. The backward trajectory analysis showed that VOCs from southwestern airmass had the highest AOC (2.0 x 10(7) molecules cm(-3) s(-1)), and the domain contributors were isoprene (39.0%), formaldehyde (24.9%), acetaldehyde (9.8%) and ethylene (4.4%). This study could provide some references for regulating AOC to alleviate O-3 pollution
Influence mechanism of original components on mechanical properties and transformation behaviors of natural bitumen
No full textNatural bitumen is an important component with high-purity organic matter in fossil energy and energy engineering scenarios. However, the production and application of natural bitumen could be severely hindered by the lacking of understanding the effects and influencing mechanisms of original components on physical properties of natural bitumen. Therefore, the main purpose of this work is to illustrate the influence mechanisms of original components (saturated hydrocarbon, aromatic hydrocarbon, resin and asphaltene) on mechanical properties of natural bitumen by the combination of nanoindentation technology and molecular structure analysis. The effects of each original component on the mechanical properties were carried out for Wuerhe natural bitumen which collected from Junggar Basin of China, and the influencing mechanisms were further revealed based on nanoindentation and X-ray diffraction (XRD) results. The occurrence units of each component in the chemical structural stacking of bitumen were established for the first time. It was found that hydrocarbons and resins can disintegrate the chemical structural stacking, thereby reducing the mechanical strength of natural bitumen. According to our micro-scale analysis results, the plastic and elastic deformation of natural bitumen were controlled by the structural units of amorphous carbon and aromatic carbon microcrystalline, as determined by saturated and aromatic hydrocarbons, respectively. And the schematic diagram of occurrence of each component in solid bitumen for the first time. Hence, the mechanical strength of natural bitumen can be effectively reduced by retaining or increasing the content of alkanes during exploitation, transportation and processing of natural bitumen. This research provided a new understanding for the stacking structure and physical property change mechanism of natural bitumen
Transport dynamics of rare earth elements in weathering crust soils
No full textIn modern industries, rare earth elements (REEs) are considered as essential metals and invaluable natural resources. Ion -adsorption deposits (IADs) are repositories of REE in the weathering crust soils, in which REEs are adsorbed on clay minerals. In the last few decades, the mining of REEs from IADs has caused substantial environmental damage owing to the overuse of leaching agents for the desorption and transport of REEs in weathering crust soils. These environmental issues have sparked extensive research interest in modeling REE transport dynamics in weathering crust soils. Nevertheless, because current models treat REE adsorption and transport independently, they do not accurately describe REE transport dynamics. Therefore, in this study, a unified workflow that synergizes adsorption and transport dynamics is proposed to predict REE transport. The adsorption of REEs on IADs was found to follow the Freundlich isotherm with the coefficient of determination exceeding 0.9826. The adsorption capacities of La 3+ , Sm 3+ , Er 3+ , and Y 3+ reach 1.3127, 1.4423, 1.5793, and 1.1061 mg g -1 at 300 ppm, respectively. For the breakthrough curve, an advection - dispersion - adsorption - eq- uation (ADAE) model was developed and utilized to accurately and reliably predict REE transport dynamics in soil columns. It was found the saturation time of REEs in soils is 39.22, 44.15, 50.64, and 32.17 h, respectively at 2 mL min -1 and decreased with the increase of flow velocity. The upper and lower limits of REE transport are ADAE-Freundlich and ADAE-Toth. More importantly, the model was applied to simulate REEs transport in fieldscale weathering crusts over 100 years and predict REE accumulation in the highly weathered layered, which is found in natural weathering crusts. The qualitative prediction of REE transport dynamics in weathering crusts may help fundamentally lower the usage of leaching agents and mitigate concomitant the environmental impacts of mining
Significance of non-DLVO interactions on the co-transport of levofloxacin and titanium dioxide nanoparticles in porous media
No full textWith the application of engineered nanomaterials and antibiotics in the fields of medicine, aerospace, new energy and agriculture, the associated contamination is detected widely in soil -groundwater systems. It is of great scientific and practical significance to deeply explore the environmental interface process between nanoparticles and antibiotics for the scientific assessment of environmental fate and ecological environmental risks, as well as the development of new composite pollution control technologies. In this study, the co -transport behaviors of positively charged titanium dioxide nanoparticles (TiO 2 -NPs) and negatively charged levofloxacin (LEV) in quartz sand (QS) are investigated in this study. The results show that TiO 2 -NPs hardly flow out when transported alone in the column because of its positive charge, which creates a strong attraction with the negatively charged quartz sand on the surface. When TiO 2 -NPs co -migrate with LEV in porous media, the presence of LEV promotes the transport of TiO 2 -NPs, while the presence of TiO 2 -NPs inhibits LEV transport. Non-XDLVO interactions based on molecular dynamics (MD) simulations can help explain the observed promotion and inhibition phenomena as well as the correlation between TiO 2 -NPs and LEV. The results indicate that TiO 2 -LEV complexes or aggregates can be formed during the co -transportation process of TiO 2 -NPs and LEV in porous media. As flow velocity increases from 0.204 cm min - 1 to 1.630 cm min - 1 , both the transport capacities of TiO 2 -NPs and LEV are enhanced significantly. Under the condition of high citric acid (CA) concentration (15 mmol L - 1 ), the transport capacity of TiO 2 -NPs is slightly inhibited, while the transport capacity of LEV is enhanced. This study provides new insights into the transport of nanometallic oxides and antibiotics in porous media, which suggests that non-XDLVO interactions should be considered together when assessing the environmental risks and fate of nanometallic oxides and antibiotics in soil -groundwater systems
Redefining timing, genesis and geodynamic setting of polymetallic skarn mineralization, Gangdese belt, Tibet, from LA-ICP-MS garnet U-Pb geochronology
No full textIron, Cu, Pb-Zn, and W-Mo skarn deposits occur in the Gangdese metallogenic belt, Tibet. A lack of precise age constraints for mineralization hinders understanding of the processes contributing to skarn mineralization, particularly identification of the causative intrusions. In this study, new garnet U-Pb geochronological data are provided for the Qiagong (Fe) and Jiaduobule (Fe-Cu) skarns. We place particular emphasis on skarn garnet mineralogy, using scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), to characterize garnet textures, compositions, and U-Pb isotope systematics. All garnets studied belong to the grossular-andradite series and display oscillatory compositional zoning (And 100 Gr 0 to And 20 Gr 80 ). Andradite-dominated garnet features a chondrite-normalized REE fractionation pattern exhibiting enrichment in LREE relative to HREE and a positive Eu anomaly, whereas grossular-dominated garnet displays relative LREE depletion and a marked flat HREE fractionation trend. Ore-forming elements, including Sn, W, As, and U, are detected at concentrations up to several hundreds of ppm in the same garnets. Concentrations of W and As are higher in andradite and correlate positively with one another. The correlation between U, Sn and the major oxide composition of garnet is insignificant, potentially resulting from the changing valence states of these elements under different redox conditions. Together with previously published and limited new data for the Gebunongba (Fe), Ri'a (Cu), and Hahaigang (W-Mo) skarns, the new garnet U-Pb age data indicate that the major Fe, Pb-Zn, and W-Mo mineralization event in the Gangdese metallogenic belt took place between 65 Ma and 50 Ma, with marked peaks at - 65 Ma and - 53 Ma. Partial melting of a crustal-dominated source due to the slab rollback (-65 Ma) and break off (-53 Ma) of Yarlug-Zangbo Tethyan Ocean and subsequent asthenosphere upwelling induced this regional event during the Paleogene to early Eocene. A less common but regionally widespread Cu (+/- Au) mineralization event in the same belt formed during the Late Cretaceous (-85 Ma) and may have resulted from the coupled influence of the northward subduction of the Yarlug-Zangbo Tethyan Ocean and the southward subduction of the Bangong-Nujiang Tethyan Ocean. This contribution highlights the potential significance of the Late Cretaceous Cu(+/- Au) event and hence the prospectivity of the belt for both skarn and porphyry systems. More broadly, our findings carry implications for Neo-Tethyan metallogeny in the region extending from southwestern China to eastern Europe during the Late Cretaceous. (c) 2024 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved
Redefining timing, genesis and geodynamic setting of polymetallic skarn mineralization, Gangdese belt, Tibet, from LA-ICP-MS garnet U-Pb geochronology
No full textIron, Cu, Pb-Zn, and W-Mo skarn deposits occur in the Gangdese metallogenic belt, Tibet. A lack of precise age constraints for mineralization hinders understanding of the processes contributing to skarn mineralization, particularly identification of the causative intrusions. In this study, new garnet U-Pb geochronological data are provided for the Qiagong (Fe) and Jiaduobule (Fe-Cu) skarns. We place particular emphasis on skarn garnet mineralogy, using scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), to characterize garnet textures, compositions, and U-Pb isotope systematics. All garnets studied belong to the grossular-andradite series and display oscillatory compositional zoning (And 100 Gr 0 to And 20 Gr 80 ). Andradite-dominated garnet features a chondrite-normalized REE fractionation pattern exhibiting enrichment in LREE relative to HREE and a positive Eu anomaly, whereas grossular-dominated garnet displays relative LREE depletion and a marked flat HREE fractionation trend. Ore-forming elements, including Sn, W, As, and U, are detected at concentrations up to several hundreds of ppm in the same garnets. Concentrations of W and As are higher in andradite and correlate positively with one another. The correlation between U, Sn and the major oxide composition of garnet is insignificant, potentially resulting from the changing valence states of these elements under different redox conditions. Together with previously published and limited new data for the Gebunongba (Fe), Ri'a (Cu), and Hahaigang (W-Mo) skarns, the new garnet U-Pb age data indicate that the major Fe, Pb-Zn, and W-Mo mineralization event in the Gangdese metallogenic belt took place between 65 Ma and 50 Ma, with marked peaks at - 65 Ma and - 53 Ma. Partial melting of a crustal-dominated source due to the slab rollback (-65 Ma) and break off (-53 Ma) of Yarlug-Zangbo Tethyan Ocean and subsequent asthenosphere upwelling induced this regional event during the Paleogene to early Eocene. A less common but regionally widespread Cu (+/- Au) mineralization event in the same belt formed during the Late Cretaceous (-85 Ma) and may have resulted from the coupled influence of the northward subduction of the Yarlug-Zangbo Tethyan Ocean and the southward subduction of the Bangong-Nujiang Tethyan Ocean. This contribution highlights the potential significance of the Late Cretaceous Cu(+/- Au) event and hence the prospectivity of the belt for both skarn and porphyry systems. More broadly, our findings carry implications for Neo-Tethyan metallogeny in the region extending from southwestern China to eastern Europe during the Late Cretaceous. (c) 2024 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved
Secondary Organic Aerosol Generated from Biomass Burning Emitted Phenolic Compounds: Oxidative Potential, Reactive Oxygen Species, and Cytotoxicity
No full textPhenolic compounds are largely emitted from biomass burning (BB) and have a significant potential to form SOA (Phc-SOA). However, the toxicological properties of Phc-SOA remain unclear. In this study, phenol and guaiacol were chosen as two representative phenolic gases in BB plumes, and the toxicological properties of water-soluble components of their SOA generated under different photochemical ages and NOx levels were investigated. Phenolic compounds contribute greatly to the oxidative potential (OP) of biomass-burning SOA. OH-adducts of guaiacol (e.g., 2-methoxyhydroquinone) were identified as components of guaiacol SOA (GSOA) with high OP. The addition of nitro groups to 2,5-dimethyl-1,4-benzoquinone, a surrogate quinone compound in Phc-SOA, increased its OP. The toxicity of both phenol SOA (PSOA) and GSOA in vitro in human alveolar epithelial cells decreased with aging in terms of both cell death and cellular reactive oxygen species (ROS), possibly due to more ring-opening products with relatively low toxicity. The influence of NOx was consistent between cell death and cellular ROS for GSOA but not for PSOA, indicating that cellular ROS production does not necessarily represent all processes contributing to cell death caused by PSOA. Combining different acellular and cellular assays can provide a comprehensive understanding of aerosol toxicological properties