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Assessment of trace metals contamination in stream sediments and soils in Abuja leather mining, southwestern Nigeria

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Acta Geochimica 2018年第4期37卷 592-613页

作者： Abiola Oyebamiji Adegbola Odebunmi Hu Ruizhong Atta Rasool State Key Laboratory of Ore Deposit geochemistry Instituteof Geochemistry Chinese Academy of SciencesGuiyang 550081 China department of Geological Services Ogun State Ministry of Commerce and Industry Oke-Mosan Abeokuta Nigeria University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Environmental geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081 China department of Science Laboratory Technology Ekiti StateUniversity Ado-Ekiti Ekiti State Nigeria

This study is aimed at determining the level of environmental degradation as well as the concentration of trace elements in soil and stream sediments in order to evaluate the environmental impact of the mining ***-five(25) soils and ten(10) stream sediment samples were collected from the study area. The physicochemical parameters were determined using appropriate instrumentation with the aid of a digital p H meter(Milwaukee meter) to measure the p H and electrical conductivity, total dissolved solids, moisture content and loss on ignition of the soil and stream sediment samples. The p H of the soil sample ranged from(6.10 to 7.19); Electrical conductivity ranged from(21.3 to 279.4 μS/cm), moisture content varied from(0.60% to 7.20%), and the LOI ranged from(2.03% to 18.62%). The results of the analysis showed that the concentrations of the trace elements in the soils and stream sediment samples were slightly higher than the background values. Plots of the trace elements in stream sediment samples show moderate, consistent decrease downstream except at points where there was mine water discharge into the main river. The pollution levels of heavy metals were examined in stream sediment and soil samples using different assessable indices, such as the enrichment factor, which showed significant-moderate enrichment for Cr, Th, Nb, Zn, Pb, Y and Zr and the geoaccumulation index, which showed practically moderate contamination with Cr, Ni and Sr based on regional background reference values. Geo-accumulation index and contamination index for soils and stream sediment revealed uncontaminated to moderate contamination. Likewise,elements with moderate contamination were Cr, Ni and *** Pearson correlation showed that there were significant positive associations among selected metals in soil and stream sediment samples.

关键词： Trace metals Stream sediments Geo-accumulation index - PCA Soil Southwestern Nigeria

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Is bicarbonate directly used as substrate to participate in photosynthetic oxygen evolution

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Acta Geochimica 2021年第4期40卷 650-658页

作者： Yanyou Wu State Key Laboratory of Environmental geochemistry Institute of GeochemistryChinese Academy of Sciences550081 GuiyangPeople’s Republic of China

If the photosynthetic organisms assimilated only CO_(2) in the Archean atmosphere,hydroxide ion in the Archean seawater would not *** plants would not consume bicarbonate as a direct substrate during photosynthesis,it is difficult to explain the evolution of Earth's *** date,it is generally accepted that photosynthetic O_(2) evolution of plants come from water ***,it should be debated by evaluating the effect of bicarbonate in photosynthetic O_(2) evolution,analyzing the role of carbonic anhydrase(CA) in photosynthetic O_(2) evolution,and the relationship between thylakoid CA and photosynthetic O_(2) *** the paper,I propose that bicarbonate is directly used as substrate to participate in photosynthetic O_(2) *** rationality of bicarbonate photolysis of plants is discussed from the thermodynamics and evolution of Earth's *** isotopic evidence that bicarbonate is not the direct substrate of photosynthetic O_(2) release is reexamined,and the new explanation of bicarbonate photolysis in photosynthetic O_(2) evolution is proposed.

关键词： Bicarbonate photolysis Carbonic anhydrase PhotosystemⅡ Photosynthesis Water photolysis

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Stable carbon isotope composition of monoterpanes in essential oils and crude oils

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Science China Earth Sciences 2010年第4期53卷 522-528页

作者： ZHANG DaJiang WANG PeiRong MAO ZhiChao XU GuanJun Research Institute of Petroleum Exploration&Development PetroChinaBeijing 100083China Key Laboratory of Petroleum geochemistry CNPCBeijing 100083China geochemistry department Yangtze UniversityJingzhou 434023China

Twenty-five monoterpanes from six types of essential oils and hydrogenated turpentine oil have been identified and their stable carbon isotope composition *** in essential oils sourced from terrestrial higher plants display a δ13C value in the range of-34‰-26‰,and mostly between-29‰ and-27‰.The δ13C value of any single monoterpane is very consistent in different essential *** monoterpanes show closer isotope composition between-28.6‰ and-26.2‰,with an average value of-27.7‰.In contrast,the isotope composition of cyclic monoterpanes is more scattered with an average value of-28.6‰.Isotopic fractionation with 13C enrichment has been observed during both artificial and geological hydrogenation of monoterpenoids to monoterpanes,and this is more obvious for the acyclic *** addition to higher plants,acyclic monoterpane 2,6-dimethylheptane in crude oil can also be originated from other organic inputs.

关键词： monoterpenoids stable carbon isotope essential oil crude oil

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Synthesis of new silicene structure and its energy band properties

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Chinese Physics B 2020年第8期29卷 270-275页

作者： Wei-Qi Huang Shi-Rong Liu Hong-Yan Peng Xin Li Zhong-Mei Huang department of Physics Hainan Normal UniversityHaikou 571158China Institute of Nanophotonic Physics Guizhou UniversityGuiyang 550025China State Key Laboratory of Environment geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550003China

Silicene,silicon analogue to graphene which possesses a two-dimensional(2D)hexagonal lattice,has attracted increasing attention in the last few years due to predicted unique ***,silicon naturally possesses a three-dimensional(3D)diamond structure,so there seems to be not any natural solid phase of silicon similar to *** we report the synthesis of new silicene structure with a unique rectangular lattice by using a coherent electron beam to irradiate amorphous silicon nanofilm produced by pulsed laser deposition(PLD).Under the irradiation of coherent electron beam with proper kinetic energy,the surface layer of silicon nanofilm can be crystallized into *** dynamic stability and the energy band properties of this new silicene structure are investigated by using first-principle calculations and density function theory(DFT)with the help of the observed crystalline structure and lattice *** new silicene structure has a real direct bandgap of 0.78 ***,the simulating calculation shows that the convex bond angle is 118°in the new silicene structure with rectangular *** DFT simulations reveal that this new silicene structure has a Dirac-cone-like energy *** experimental realization of silicene and the theoretically predicted properties shed light on the silicon material with potential applications in new devices.

关键词： silicene nanofilm irradiation of coherent electron beam pulsed laser deposition Dirac cone

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Reservoir geochemistry of the Tazhong Oilfield in the Tarim Basin, China, Part II. Migration, accumulation and mixing of crude oils

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Chinese Journal Of geochemistry 2007年第2期26卷 157-162页

作者：张敏黄光辉胡国艺 department of geochemistry Yangtze University Langfang Branch of China Institution of Petroleum Exploration and Development

Measurements of the absolute and relative concentrations of nitrogen-containing compounds in crude oils from different reservoir strata (Ordovician, Silurian and Carboniferous) in the Tazhong region of the Tarim Basin, Xinjiang, China, showed that even though there are quite a number of factors affecting the distributional and compositional characteristics of neutral nitrogen-containing compounds in crude oils, the distributional and compositional characteristics of crude oils whose source conditions are approximate to one another are influenced mainly by the migration and fractionation effects in the process of formation of oil reservoirs. In addition, crude oils in the Tazhong region show obvious migration-fractionation effects in the vertical direction. Carboniferous crude oils are characterized by high migration parameters and low compound concentrations, just in contrast to Ordovician crude oils. This indicates that crude oils from shallow-level oil reservoirs were derived from those of deep-level oil reservoirs via faults, unconformable contact or carrier beds. Crude oils from the Tazhong region show some migration-fractionation effects in the lateral direction, but mixing of crude oils derived from different hydrocarbon source rocks in the process of formation of oil reservoirs made it more complicated the migration and accumulation of crude oils, as well as the formation of oil reservoirs.

关键词：塔里木盆地塔中油田储层地球化学原油运移原油积聚混合

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Phase Equilibrium of Quaternary System Cd^(2+)//Cl^-,SO_4^(2-),NO_3^--H_2O at 298 K

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Chemical Research in Chinese Universities 2011年第3期27卷 482-485页

作者： HUANG Yi ZOU Fang NI Shi-jun SANG Shi-hua department of geochemistry Chengdu University of Technology Chengdu 610059 P. R. China

Solid-liquid equilibrium of quaternary system Cd2＋//Cl–, SO42–, NO3–-H2O at 298 K was studied by means of an isothermal solution saturation method. Experimental results indicate that there are three univariant curves BE, AE and CE, one invariant point E and three crystallization fields in the quaternary system. The quaternary system belongs to a simple type, and there are no double salts or solid solution existing. The crystallization zones of equilibrium solid phases are CdCl2·5/2H2O（AEB field）, 3CdSO4·8H2O（AEC field） and Cd（NO3）2·4H2O（BEC field）, respectively. The composition of the invariant point is CdCl2, Cd（NO3）2, CdSO4 and H2O and the contents of which are 17.02%, 45.50%, 4.52% and 32.96%, respectively. The physico-chemical properties of solution in the quaternary system show regular changes along with the increased cadmium concentration. The results indicate that Cd（NO3）2 possessed the highest solubility among those three salts, which means a strong transfer of Cd ion and a high pollution risk of soil environment. And the solubility of CdSO4 would be restrained as the salts existing together.

关键词： Cadmium Quaternary system Isothermal method Solid-liquid equilibrium

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Study on the carbonate ocelli-bearing lamprophyre dykes in the Ailaoshan gold deposit zone,Yunnan Province

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Science China Earth Sciences 2002年第6期45卷 494-502页

作者：黄智龙韩润生钟昆明许成刘丛强李文博肖化云 1. Open Laboratory of Ore Deposit geochemistry Institute of Geochemistry Chinese Academy of Sciences 550002 Guiyang China 2. department of Geology Kunming University of Science and Technology 650093 Kunming China

Three carbonate ocelli-bearing lamprophyre dykes have been found in the Laowangzhai and Beiya gold orefields in the northern sector of the Ailaoshan gold deposit zone, Yunnan Province. Ocelli in the lamprophyre dykes are carbonates composed mainly of dolomite and calcite. Their trace elements, REE and C isotopic compositions are characteristic of carbonatite and the main mineral assemblages, major elements, trace elements and REE in the matrix are similar to those in the carbonate ocelli-barren lamprophyre dykes in the orefields, which are calc-alkaline lamprophyres that derived from the fertile mantle. The results indicate that the carbonate ocelli-bearing lamprophyre dykes in this area were produced at the time when the Himalayan lamprophyre magma evolved to a relatively late stage of silicate-carbonate liquid immiscibility. In the process of magmatic evolution there took place magmatic degassing with CO2 and H2O as the dominant released gases.

关键词： carbonate ocelli-bearing lamprophyre dyke, magmatic liquid immiscibility, magmatic degassing, Ailaoshan gold deposit zone.

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Theoretical Study of Small Water Clusters of Sulfur Dioxide

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Chinese Journal of Structural Chemistry 2010年第4期29卷 499-508页

作者：赵亚英曾永平张锡辉陶福明 Research Center of Environmental Engineering and Management Graduate School at Shenzhen Tsinghua University State Key Laboratory of Organic geochemistry Guangzhou Institute of GeochemistryChinese Academy of Sciences department of Chemistry and Biochemistry California State University

The intermolecular clusters of sulfur dioxide with water, SO2（H2O）n （n = 2～5）, are studied by using B3LYP density functional theory and MP2 ab initio methods along with the large basis sets （6-311＋＋G（d,p） and aug-cc-pVDZ）. The equilibrium geometries, intermolecular binding energies, and anharmonic frequencies of the clusters are calculated and compared with those of pure water clusters and available experiments. SO2 tends to form cyclic hydrogen-bonded complexes with two or three water molecules. In the larger clusters, however, water molecules begin to retain the structure of pure water clusters and segregate from SO2. Infrared absorption assignments for the small clusters are discussed to resolve a possible incorrect assignment in a recent spectroscopic experiment on the clusters.

关键词： SO Theoretical Study of Small Water Clusters of Sulfur Dioxide LYP MP

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Petrology and geochemistry at the Lower zone-Middle zone transition of the Panzhihua intrusion,SW China:Implications for differentiation and oxide ore genesis

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Geoscience Frontiers 2013年第5期4卷 517-533页

作者： Kwan-Nang Pang Mei-Fu Zhou Liang Qi Sun-Lin Chung Chiu-Hong Chu Hao-Yang Lee department of Geosciences National Taiwan University department of Earth Sciences The University of Hong Kong Institute of geochemistry Chinese Academy of Sciences

A sequence of gabbros showing isotropic,layered and fine-grained textures is exposed in the Nalaqing mine at the southern tip of the～260 Ma Panzhihua intrusion,SW *** field relations,structure,texture and mineralogy of the rocks indicate that the sequence represents the transition between the Lower zone and Middle zone of the *** gabbros characteristic of the Lower zone pass upward to layered gabbros of the Middle zone through a～5 m-thick microgabbro sheet,within and close to which small-scaled, concordant Fe-Ti oxide ore horizons are *** fractionation between HFSE and REE in a subset of samples is ascribed to cumulus titanomagnetite into which HFSE are preferentially incorporated over REE,as reflected in the parallel relations between Nb/La,Hf/Sm and Ti/Ti＊.Both the isotropic and layered gabbros display cumulate textures and have similar mineral compositions（Mg# of clinopyroxene =～76-79 and An59-61）,isotopic compositions[（87Sr/86Sr）i = 0.7044-0.7045 andεNd（t） = ＋2.4 to ＋3.9]and trapped liquid contents inferred from Zr abundance（～17-34 ppm）.However,there are substantial variations in elemental abundances（V,Cr and PGE） and ratios（Ti/V,La/Yb,Ba/Y and Cu/Pd） between the two types of gabbros,features that cannot be explained by cumulate formation from a common magma in a closed *** microgabbros generally resemble high-Ti Emeishan basalts in major element compositions,but their low trace element abundances indicate some lost of residual liquid is inevitable despite rapid nucleation and *** with available data and observations,we propose a model involving in-situ crystallization,followed by magma recharge and closed-system fractionation to explain the formation of texturally distinctive gabbros at Nalaqing and the evolution of the lower part of the Panzhihua intrusion.

关键词： Fe-Ti oxides Layered intrusion Microgabbro Panzhihua Emeishan

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Pressure Effect on K Diffusion in Hydrated Granitic Melt

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Science China Chemistry 1994年第7期37卷 879-886页

作者：柏天宝 A.F.Koster van Groos Also Institute of geochemistry Academia Sinica University of Illinois at Chicago Department of Geological Sciences

The chemical diffusivity of K in a hydrated granitic melt was determined at temperatures of750-900℃ and pressures between 1 and 5.6 kbar.K diffusion follows the Arrhenius equation,its activationenergy is about 20 kcal/mole and the activation volume is about 20 cm^3/mole under the conditions *** diffusivity of K was found to be very sensitive to *** results of this study could be used toevaluate K diffusion in various geological situations.

关键词： K diffusion pressure effect

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