黄河水氢、氧同位素组成的空间变化特征及其环境意义

2005年7月从黄河源头到渤海人海口沿黄河干流系统采集了24个水样,对水的氢氧同位素组成进行了分析.黄河水δD和δ18O值的变化范围分别为-91‰～-44‰和-12.4‰～-4.2‰,并且二者都表现出从上游到下游整体逐渐上升的趋势,但青海玛多样品除外.黄河水δ18O和δD的线性关系方程为δD=5.69×δ18O-15....     

硅岩的Rb-Sr同位素组成特点及其地质意义

通过对扬子地台和东昆仑山地区的不同时代、不同成因、成分上差异较大的硅岩Rb-Sr同位素组成的对比研究，探讨其物源和形成环境，利用所测Rb-Sr等时线年龄，有效的解决硅岩的地层年代，开创硅岩测年的应用前景。     

硅同位素测量方法及其地质应用

建立了硅同位素测量方法,获得了比前人更高的测量精度。分析了52个地质样品,探讨了硅同位素地质应用的前景。     

长江水中悬浮物含量与矿物和化学组成及其地质环境意义

在2003～2007年间,在长江干流的25个水文站及主要支流的13个水文站系统采样,对悬浮物的含量及其矿物与化学组成系统地进行了测定。根据这些数据,对长江悬浮物的矿物和化学组成的时空变化及其地质与环境意义进行了系统研究。 本次所采样品中悬浮物含量平均值为256.5mg/L,在世界各大河中居于中等水平。悬浮物含量呈现大幅度的时空变化,与水流速度、径流量及泥沙供给情况的变化相对应,受河床坡度、降雨量、风化强度、侵蚀情况及人工活动等多种因素的影响。近年来,长江悬浮物含量逐渐下降,与上游的退耕还林和水库建设密切相关。特别是三峡水库工程引起泥沙在库区大量沉积,显著降低河水的悬浮物含量,导致其下游河段堤岸冲刷加剧,洞庭湖、鄱阳湖和长江口的沉积减少。这种变化带来的环境效应巨大,需要慎重评估和应对。 长江水中悬浮物主要由粘土矿物、碎屑硅酸盐矿物和碎屑碳硅酸盐矿物组成,并含有少量重矿物、氢氧化物和有机物。与黄河悬浮物矿物组成的对比研究表明长江流域的化学风化作用明显强于黄河流域,而物理侵蚀作用明显弱于黄河流域。由上游到下游,长江悬浮物中粘土和碎屑硅酸盐矿物逐渐增高,而碎屑碳硅酸盐逐步降低,与中下游地区气候变得湿热,化学风化变强的情况相对应。 与上地壳岩石平均值相比,长江悬浮物的SiO2、CaO、K2O 、Na2O含量较低,而TFe2O3含量较高,反映硅酸盐矿物化学风化过程中部分硅、钾、钠、钙的流失和铁的富集。与全球河流悬浮物和黄河悬浮物相比,长江悬浮物的SiO2、Na2O含量较低,反映长江流域的化学风化作用较强。与长江水系沉积物相比,长江悬浮物的SiO2、Na2O含量较低,而Al2O3、K2O 、MgO、TFe2O3较高,反映悬浮物比较富含粒度较小的粘土与铁质成分。从上游往下游,长江悬浮物中CaO、MgO含量逐渐降低,SiO2 含量逐步升高,与粘土矿物含量增高和碳酸盐含量降低的趋势相对应。 长江悬浮物中Co、Ni、Cu、Zn、Pb、Cd含量均高于上地壳岩石的平均含量,可能由这些元素在风化过程优先为粘土所吸附所引起。在攀枝花、宜宾、九江、大通、南京等站悬浮物中发现的铜、铅、锌的高含量,可能均与相关地段采矿活动有关。2005年7月在富顺和长沙发现Cd的高异常值引人注目。悬浮物中Cu、Pb、Zn、Cd的含量较长江水系沉积物的平均含量高出数倍、乃至数十倍,可能反映近年来流域采矿活动加剧,其对流域环境的长远影响值得关注。 长江悬浮物的稀土总量与全球页岩的平均值相比略显偏高。长江悬浮物的REE分布形式于上地壳基本一致,表明长江流域出露的岩石的化学组成与上地壳岩石平均组成没有明显差别,而且岩石风化过程中稀土元素未出现明显分馏。     

陕西八卦庙金矿床硅同位素组成及地质意义

作卦庙金矿床是秦岭泥盆系地层中发现的特大型金矿床。矿床分布于佛坪隆起西缘增生体向西侵入的前锋区,赋矿岩层为上泥盆统底部铁白云质粉砂千枚岩。矿床受区域ＮＷ向剪区断裂,ＮＥ间断裂与解理密集带交汇部控制。硅同位素组成有两组,分别与本地区泥盆系地层热水沉积物和印支－燕山期中酸性岩浆岩硅同位素相近,表明成矿流体早期以地层为源主,晚期在岩浆源为主。     

花溪河水碳同位素的季节变化及其环境意义

碳的全球生物地球化学循环是与全球变化相关的一系列重大国际合作计划的主要研究内容之一.     

黄河水δ18O、δD和3H的沿程变化特征及其影响因素研究

根据2000年8～9月雨季和2001年3～4月旱季在黄河18条断面上河水的同位素测试结果，分析了黄河水占δ^18O、δD和^3H浓度的沿程变化特征。研究结果发现，从黄河源头至入海口，黄河水具有稳定同位素比率逐渐增大而^3H浓度逐渐下降的趋势；外来水体的混合作用、蒸发作用以及人类活动对黄河水的同位素具有明显的影响。黄河源头地区和中游地区是黄河两个主要的产流区，河水同位素的变化是不同径流来源对河水补给的良好标志。兰州以上黄河源头地区河水的δ^18O、δD的季节性变化与雨水相反，地下水对河水的补给贡献旱季大于雨季。晋陕峡谷北段雨季δ^18O相对较低的岩溶水和当地雨水对河川径流有明显的补给，而旱季^3H浓度相对较低的岩溶水对河川径流有一定的补给；吴堡—潼关段雨季和旱季均有同位素比率相对较高的地表支流(如汾河、渭河)的加入。河水水面蒸发作用对兰州—包头段和黄河下游段旱季河水的δ^18O具有明显的影响，而对这些河段雨季河水的同位素影响较小，灌溉回归水的蒸发可能是影响这些地段河水同位素组成的主要因素。     

燕山地区铁岭组稳定同位素组成特征及其地质意义

测定的样品采自天津蓟县和北京门头沟青白口两地铁岭组碳酸盐,测得152对δ~(13)C和δ~(18)O数据,发现碳、氧同位素在两地铁岭组具有相同的变化趋势,并对它们的成因机制和地质意义进行了对比及探讨。     

福建李坊重晶石矿床中硅质岩硅、氧同位素组成及成因意义

福建李坊大型重晶石矿床围岩中发育层状硅质岩,为了研究硅质岩的成因,本文对14件硅质岩样品进行了硅、氧同位素分析。结果表明:δ(³⁰Si)分布范围为-0.3×10^-3～+0.1×10^-3,平均值为-0.1×10^-3;δ(¹⁸O)分布范围为10.6×10-3～18.9×10-3,平均值为14.7×10^-3。基于该层状硅质岩的δ(³⁰Si)和δ(¹⁸O)分布范围特征,结合野外地质调查研究工作的认识,该硅质岩应为原生沉积成因,二氧化硅来源于热水沉积;根据燧石-海水氧同位素地质温度计估算石英的形成温度为100.2℃—198.7℃,平均值为146.0℃,即该硅质岩形成于热水沉积,暗示李坊重晶石矿床形成于热水沉积作用。     

黄河悬河研究及其专家系统研制

本文在分析了大量研究资料的基础上,提出了一套以地壳,堤坝和地基三系统控制论为理论基础,以工程治理与环境治理,环境治理与经济发展,地质工程治理与水利工程治理相结合为治理对策的研究思路,在此基础上,利用人工智能技术,研制了黄河下游悬浮河稳定性评价专家系统（ＳＳＲＰＰ系统）,并运用该系统对黄河下游悬河郑州铁桥－彭楼集段等进行了稳定性分析,评价结果与实际情况吻合。     

黄河内蒙古段上覆水、悬浮物和底泥重金属特征及生态风险研究

系统地采集黄河内蒙古段上覆水、悬浮物和底泥样品,分析其中重金属元素的含量。采用地质累积指数法和潜在生态危害系数法,研究了黄河干流内蒙古段的上覆水、悬浮物和底泥的重金属沿程分布特征、污染程度和生态风险。分析结果显示:除了As元素,悬浮物中重金属元素含量总体上高于底泥中的含量。地质累积指数法评价结果表明:悬浮物和底泥属于无污染—中度污染,悬浮物总体上比底泥污染严重;潜在生态危害系数法评价结果表明:底泥和悬浮物中重金属的生态危害总体上属轻微状态;因此,生态风险指数法和地质累积指数评价结果基本一致。     

Suspended sediment dynamics and morphodynamics in the Yellow River, China

The Yellow River in China carries large amounts of sediments in suspension at concentrations up to several hundreds of kilograms per cubic metre; the sediment is composed mainly of silt. These high sediment concentrations influence the hydrodynamics (flow velocity and turbulence) which, in turn, determine the sediment concentration profile, whereas both the high sediment concentrations and pseudo-cohesive properties of silt determine the morphodynamics of the Yellow River. The effect of sediment on the hydrodynamics is analysed using the Richardson number and the Reynolds number to provide a framework to differentiate between various flow regimes in the Yellow River, which is calibrated and validated with Yellow River data. The flow may be sub-saturated (stable flow), super-saturated (unstable flow characterized by high deposition rates, caused by collapse of turbulence), or hyperconcentrated sub-saturated (stable flow because of hindered settling effects), depending on the Richardson number. Independent of this, the flow may be turbulent, transitional or laminar, depending on the Reynolds number. Analysis of these flow types improves understanding of the flow regimes and morphodynamics of the Yellow River. The morphodynamics of the Yellow River are also affected by pseudo-cohesive behaviour caused by shear dilatance, which results in increasing critical shear stress for erosion at decreasing grain-size. This pseudo-cohesive behaviour may be partly responsible not only for the high deposition rates which characterize the lower Yellow River, but also for mass erosion during river floods.     

黄河包头段颗粒物中轻稀土元素的分布特征

干流表层沉积物和悬浮物中各轻稀土元素的总量、非稳定态及非稳定态之和的横向分布特征,以及稀土元素的配分模式和地球化学特征参数均揭示,来自包头市工业废水的外源轻稀土元素对黄河包头段干流具有一定的迭加作用;柱状沉积物中各轻稀土元素的含量、非稳定态及其非稳定态之和的纵向变化规律则揭示,这种迭加作用呈逐年递减之势,但又由于支流柱状沉积物中非稳定态稀土元素的含量较高,从而仍有对干流产生进一步迭加的潜势。     

An Overview of Dissolved and Suspended Matter Fluxes in the Loire River Basin: Natural and Anthropogenic Inputs

The spatial and temporal distributions of major elements were investigated in the surface waters and in associated suspended matter at two sites of the upper Loire basin (Orleans and Brehemont) between 1995 and 1998.According to geochemical and isotopic patterns, the dissolved load appears to result from a process of mixing rainwater inputs, weathering processes of carbonate and silicate bedrock, and agricultural and urban inputs. Natural inputs influence 60% of water chemical composition at both sites. Annual dissolved fluxes were estimated to be 1300 10³ t/y at Orleans and 1620 10³ t/y at Brehemont. Major elements are transported mainly in the dissolved fraction. After correcting for atmospheric and anthropogenic inputs, the silicate specific export rate was calculated to be 11 t/y/km² throughout the basin and the carbonate specific export rate to be from 47 t/y/km² at Orleans to 23 t/y/km² at Brehemont.The suspended load appears to result from at least two particle reservoirs: a silicate reservoir and a carbonate reservoir. The silicate reservoir has a detrital origin, mainly during periods of high flow, while the carbonate reservoir has a detrital origin during periods of high flow and an authigenic origin during periods of low flow. Of the total annual flow of suspended matter, this authigenic material represents 16% at Orleans, 25% at Brehemont and 37% in the fluvial part of the estuary. After correcting authigenic inputs, the specific export rate due to mechanical weathering was estimated to be 8 t/y/km² throughout the Loire basin.     

Chemical and Isotopic Characters of the Water and Suspended Particulate Materials in the Yellow River and Their Geological and Environmental Implications

The chemical and isotopic characteristics of the water and suspended particulate materials(SPM)in the Yellow River were investigated on the samples collected from 29 hydrological monitoring stations in the mainstem and several major tributaries during 2004 to 2007.TheδD andδ~(18)O values of the Yellow River water vary in large ranges from-32‰to-91‰and from-3.1‰to-12.5‰,respectively.The characters of H and O isotope variations indicate that the major sources of the Yellow River water are meteoric water and snow melting water,and water cycle in the Yellow River basin is affected strongly by evaporation process and human activity.The average SPM content(9.635g/L)of the Yellow River is the highest among the world large rivers.Compared with the Yangtze River,the Yellow River SPM has much lower clay content and significantly higher contents of clastic silicates and carbonates.In comparison to the upper crust rocks,the Yellow River SPM contains less SiO_2,CaO,K_2O and Na_2O,but more TFe_2O_3,Co,Ni,Cu,Zn,Pb and Cd.The abnormal high Cd contents found in some sample may be related to local industrial activity.The REE contents and distribution pattern of the Yellow River SPM are very close to the average value of the global shale.The averageδ~(30)Si_(SPM)in the Yellow River(-0.11‰)is slightly higher than the average value(-0.22‰)of the Yangtze River SPM.The major factors controlling theδ~(30)Si_(SPM)of the Yellow River are the soil supply,the isotopic composition of the soil and the climate conditions.The TDS in the Yellow River are the highest among those of world large rivers.Fair correlations are observed among Cl~-,Na~+,K~+,and Mg~(2+)contents of the Yellow River water,indicating the effect of evaporation.The Ca~(2+)and Sr~(2+)concentrations show good correlation to the SO_4~(2-)concentration rather than HCO_3~-concentration,reflecting its origin from evaporates.The NO_3~-contents are affected by farmland fertilization.The Cu,Zn and Cd contents in dissolved load of the Yellow River water are all higher than those of average world large rivers,reflecting the effect of human activity.The dissolved load in the Yellow River water generally shows a REE distribution pattern parallel to those for the Yangtze River and the Xijiang River.Theδ~(30)Si values of the dissolved silicon vary in a range from 0.4‰to 2.9‰,averaging1.34‰.The major processes controlling the D_(Si)andδ~(30)Si_(Diss)of the Yellow River water are the weathering process of silicate rocks,growth of phytolith in plants,evaporation,dissolution of phytolith in soil,growth of fresh water diatom,adsorption and desorption of aqueous monosilicic acid on iron oxide and human activities.The averageδ~(30)Si_(Diss)value of the Yellow River is significantly lower than that of the Nile River,Yangtze River and Siberia rivers,but higher than those of other rivers,reflecting their differences in chemical weathering and biological activity.Theδ~(34)S_(SO4)values of the Yellow River water range from-3.8‰to 14.1‰,averaging 7.97‰.There is some correlation between SO_4~(2-)content andδ~(34)S_(SO4).The factors controlling theδ~(34)S_(SO4)of the Yellow River water are the SO_4 in the meteoric water,the SO_4 from gypsum or anhydrite in evaporite rocks,oxidation and dissolution of sulfides in the mineral deposits,magmatic rocks and sedimentary rocks,the sulfate reduction and precipitation process and the sulfate from fertilizer.The~(87)Sr/~(86)Sr ratios of all samplesrange from 0.71041 to 0.71237,averaging 0.71128.The variations in the~(87)Sr/~(86)Sr ratio and Sr concentration of river water are primarily caused by mixing of waters of various origins with different~(87)Sr/~(86)Sr ratios and Sr contents resulting from water-rock interaction with different rock types.     

金沙江河流悬浮物与沉积物的矿物学特征及其表生地球化学意义

为研究金沙江流域表生风化特征,系统采集了金沙江和岷江流域32件河流悬浮物和河床砂样品,对其进行了矿物组成分析。结果表明,不同江段河流悬浮物、沉积物的矿物组成大致相同,以石英、方解石、斜长石和粘土矿物为主,局部有白云石、钾长石和角闪石等;粘土矿物主要有伊利石、绿泥石、高岭石和蒙脱石。河床沉积物中非粘土矿物碎屑(岩屑)含量明显高于悬浮物。伊利石为铁镁质,Kubler指数在轻微变质范围内,主要来源于三叠系碎屑岩和砂板岩。金沙江、岷江的河流悬浮物矿物组成与流域内出露的碎屑岩、砂板岩、火成岩、碳酸盐岩等的分布有较好的对应关系。河流悬浮物和沉积物的矿物组成及伊利石结晶指数特征表明流域内以物理风化为主。     

Geochemistry of Suspended Particulate Matter (SPM) in the Murray-Darling River System: A Conceptual Isotopic/Geochemical Model for the Fractionation of Major, Trace and Rare Earth Elements

A conceptual isotopic/geochemical model is presented to explain the variation of major, trace and rare earth element (REE) geochemistry and Sr isotope systematics in suspended particulate matter (SPM) as a function of particle/colloid size. This conceptual model is an extension of a previous investigation of the origin of SPM in the Murray-Darling River system (MDRS) that utilised Sr isotope systematics to examine aspects of SPM (particle/colloid) origin, structure and mineralogy. The geochemical processes that give rise to the often coherent trends in major, trace and REE geochemistry and Sr isotopic signature as a function of particulate (<1 μm) and colloidal (>1 μm) size in the MDRS have been identified using an enhanced SPM size fractionation technique as a basis to not only obtain a broad range of particle/colloid size ranges, but also to provide sufficient material for subsequent geochemical and isotopic analysis. The conceptual isotopic/geochemical model proposed here contains three major components: (i) the differential weathering of micas and alkali (K-) feldspars to form the majority of the particulate (<1 μm) fractions (high 87Sr/86Sr ratio), which have a geochemical and Sr isotopic signature that closely resembles precursor mineralogies, (ii) the differential weathering of Na, Ca-feldspars (plagioclase) which decompose to form clay minerals in the colloidal (>1 μm) fractions (low 87Sr/86Sr ratio), with a range of geochemical signatures related to the relative proportions of inorganic and organic constituents, and (iii) the presence of natural organic matter as coatings on the particulate (<1 μm) and colloidal (>1 μm) matter and possibly as organo-colloids which exert an increasing influence in particular on bulk colloid geochemistry with decreasing colloid size. This conceptual isotopic/geochemical model also accounts for the distinct variation in major, trace and REE geochemistry and Sr isotopic systematics between the particulate (<1 μm) and colloidal (>1 μm) fractions, the variation being primarily a function of the distinctly different precursor mineralogies of the SPM fractions and geochemical fractionation during the weathering and transport. Additionally, this model explains a systematic fractionation of REE apparent within colloidal (>1 μm) fractions. Statisitcal (hierachical cluster) analysis of two particulate and three colloidal fractions from 23 samples from the MDRS is used as a basis to investigate geochemical and mineralogical associations within the particulate and colloidal size fractions and to provide additional supporting evidence for the conceptual isotopic/geochemical model. This revised version was published online in July 2006 with corrections to the Cover Date.     

陕西旬阳地区小河金矿硫铅同位素组成及地质意义

小河金矿是近年来在南秦岭中带发现的中型金矿床,矿石类型为微细浸染型,矿床受地层和构造双重控制。在野外工作基础上,根据矿物组合及穿插关系划分了4个成矿阶段:Ⅰ,成矿早期少硫化物石英脉成矿阶段;Ⅱ,石英脉、黄铁矿、毒砂成矿主阶段;Ⅲ,石英脉-多金属硫化物成矿主阶段;Ⅳ,方解石、石英脉成矿晚阶段。其中Ⅱ、Ⅲ阶段是主要金矿化阶段。不同阶段样品的原位硫同位素结果显示:成矿早阶段石英脉期的黄铁矿δ³⁴S值为20.80‰~25.77‰,均值为23.59‰;主成矿期II阶段中黄铁矿、毒砂δ³⁴S值为15.46‰~19.12‰,均值为17.5‰;主成矿期Ⅲ阶段中方铅矿、闪锌矿δ³⁴S值为11.35‰~16.78‰,均值为13.88‰。硫同位素特征指示硫以沉积硫为主,成矿过程可能存在低δ³⁴S值热液的持续加入。金属硫化物Pb同位素测试结果显示²⁰⁶Pb/²⁰⁴Pb为17.882 1~18.367 4,²⁰⁷Pb/²⁰⁴Pb为15.614 0~15.674 1,²⁰⁸Pb/²⁰⁴Pb为38.016 3~38.934 2,指示小河金矿铅主要源于地壳,同时伴随幔源铅的混入。综合矿床地质特征及硫、铅同位素地球化学特征,认为小河金矿成矿过程可能存在流体混合作用。     

长江干流丰水期河水硫酸盐同位素组成特征及其来源解析

碳酸盐岩的硫酸风化机制及其与碳循环的关系是全球碳循环研究中最为关注的科学问题之一, 其关键问题是识别硫酸盐来源.通过分析长江干流丰水期SO₄2-浓度及其硫、氧同位素组成特征, 探讨长江硫酸盐的来源及其主要控制因素.长江河水SO₄2-含量呈现逐年增加的趋势, 并且年增幅度逐渐加大.δ34S_SO4和δ18O_SO4变化范围为-3.5‰~5.6‰和3.7‰~9.2‰, 二者呈现显著的线性负相关关系.δ18O_SO4值从上游到下游的增加趋势受长江水δ18O_H2O值的空间组成特征的影响.研究表明, 大气降水(酸雨)和硫化物氧化是控制长江干流丰水期河水硫、氧同位素组成及其来源的主要机制, 为研究长江流域化学风化侵蚀作用和碳循环过程提供重要的理论依据.