吉林小西南岔金-铜矿床成矿流体地球化学特征及矿床成因研究

小西南岔金-铜矿床产于海西期花岗闪长岩-石英闪长岩体之中,其矿化类型以石英大脉及石英细脉带型金-铜矿化为主,局部地段叠加发育有石英脉型辉钼矿化。流体包裹体研究结果表明,矿区金-铜矿脉及辉钼矿脉石英中均主要发育含NaCl子矿物三相、气相-富气相及气液两相三种类型的原生流体包裹体,同类包裹体均一温度、盐度等参数相近,显示两类矿化成矿流体具有相似的地球化学性质,氢-氧同位素研究结果反映它们均主要来源于岩浆热液。辉钼矿Re-Os同位素定年研究表明区内辉钼矿化主要发生于109Ma±,而金-铜矿脉石英的40Ar-39Ar同位素定年结果表明金-铜矿化则主要发生于123.35±0.8Ma。结合矿区已有的岩浆岩年代学研究成果,提出小西南岔矿区金-铜矿化主要与燕山晚期细粒(花岗)闪长岩活动有关,而辉钼矿化则与其后侵位的隐伏花岗斑岩活动有关的认识。     

云南省铝元素地球化学特征及资源远景

云南铝成矿地质条件较好,分岩浆型和沉积型。铝地球化学异常特征复杂,呈带、呈区分布。对成矿地球化学分析后,圈定找矿远景区。以典型矿床为基础,对铝矿资源进行预测评价。     

塔里木盆地寒武系—下奥陶统白云岩成因及识别特征

对63口井岩心及薄片的观察以及大量阴极发光、碳氧同位素、包裹体及电子探针能谱的分析,认为塔里木盆地寒武系—下奥陶统白云岩主要有四种成因,分别对应有四种白云岩类型,即萨布哈白云岩、渗透回流白云岩、埋藏白云岩和热液白云岩。前两者受沉积相控制,后两者受成岩相控制。萨布哈白云岩发育于同生—准同生期蒸发成岩环境的潮间—潮上坪,渗透回流白云岩发育于同生—准同生期蒸发成岩环境的澙湖中,埋藏白云岩发育于埋藏期的深、浅埋藏环境,热液白云岩发育于埋藏期的深埋藏环境。总结了四种不同成因的白云岩的岩石特征及地球化学特征。认识到叠合盆地古老海相地层的白云石化机理复杂,白云岩类型多样,白云岩结构特征不但与沉积相密切相关,更受埋藏期白云石化作用的叠加改造。     

南京市心脑血管疾病的医疗气象预报研究

以2003年1月至2008年7月南京市某医院的心脑血管逐日就诊人数为样本,首先根据其时间分布特征采用虚拟变量选择包含节假日等的22个非气象因子,然后通过逐步回归法筛选气象因子和非气象因子,得到最终模型的解释变量,采用支持向量机(SVM)回归方法分别构建了南京市心、脑血管疾病预测模型。将就诊人数分为5个等级,通过反查,模型针对心、脑血管疾病在同一等级和差一等级的准确率分别为87.91%和84.62%,实际预测结果较好,证明该模型具有较高的实际应用价值。     

Hydrogeochemical modeling of the water seepages through Tannur Dam,southern Jordan

This paper reveals the geochemical processes of dissolution, precipitation and cation exchange that took place during water–rock interaction between water seepages through the Tannur Dam. The Schoeller diagram indicates that there are three major water types originating during water–rock interaction. The first water type is characterized by low salinity that ranges from 1,300 to 2,800 µs/cm, which represents the reservoir water and the water in the right side of the central gallery. The second water type is in the left side of the central gallery, which exhibits medium salinity that reaches about 4,400 µs/cm. The third water type is characterized by very high salinity that reaches a value of around 8,500 µs/cm and represents the water in the right existing adit. The increase of salinity can be explained due to the dissolution of carbonate and sulfate minerals that form the matrix of the foundation and the abutment rocks, and the dissolution of the grout curtain, which is composed of cement and bentonite. Hydrogeochemical modeling, using a computer code PHREEQC, was used to obtain the saturation indices of specific mineral phases, which might be related to interaction with water seepages, and to identify the chemical species of the dissolved ions. The thermodynamic calculations indicate that most of the water samples were undersaturated with respect to gypsum, anhydrite and halite, and were saturated and/or supersaturated with respect to calcite and dolomite. Ca(HCO₃)₂ is the primary water type, as a result of dissolution of carbonate minerals such as calcite and dolomite prevailing at the dam site. However, cation-exchange processes are responsible for the formation of the Na₂SO₄ water type from the CaSO₄ type that formed due to the dissolution of gypsum.     

The influence of cyanide complexation on the speciation and solubility of radionuclides in a geological repository

Prussian Blue, Fe^III ₄[Fe^II(CN)₆]₃, and structurally related transition metal compounds are used as cesium ion exchangers in decontamination procedures of liquid radioactive waste. The used ion exchangers are conditioned as a cementitious waste form for interim storage and finally will become part of the radioactive waste in geological repositories. The problem discussed here is the long-term behaviour of the ion exchangers Fe^III ₄[Fe^II(CN)₆]₃ and Ni₂[Fe(CN)₆] in planned geological repositories. The worst-case scenario is the instantaneous and complete dissolution and decomposition of the ion exchangers in the cementitious environment and the release of free cyanide. All radionuclides belonging to the class of hard acceptors, e. g. Cs, Sr, Ra, U, Np, Pu, Am and Cm, are not affected by cyanide complexation under these conditions. Radionuclides belonging to the class of soft acceptors and borderline metals, e.g. Co, Ni, Tc, Cd, Pb, Pd and Ag, are affected to various degrees by cyanide complexation. Strong complexation and extensive cyanide leaching is found for Ni, Co, Pd, Ag.     

雅鲁藏布江大峡谷地区环境地球化学与地方病

雅鲁藏布江大峡谷地区地方性群发性骨骼生育疾病严重影响区域居民健康和经济社会发展。中国地质调查局在雅鲁藏布江大峡谷腹地部署了波密幅墨脱县幅区域地球化学调查．成果表明．大峡谷地区环境地球化学特征是生命元素Fe、P、Ca、Mg、Mn、Co、Zn偏低，Cu、Mo、Cr、V、Ni明显偏低，毒性元素Ba、Be、Sr、Li偏高，U、Th明显偏高．P／F、Sr／Ca、Ba／Ca比例失调。地方病的发生与环境地球化学质量低下有密切关系。大峡谷地区板块运动造成的大规模物质交换和特殊的地球化学景观是环境地球化学质量低下和地方病产生的深层次原因。     

Mixing of shallow and deep groundwater as indicated by the chemistry and age of karstic springs

Large karstic springs in east-central Florida, USA were studied using multi-tracer and geochemical modeling techniques to better understand groundwater flow paths and mixing of shallow and deep groundwater. Spring water types included Ca–HCO₃ (six), Na–Cl (four), and mixed (one). The evolution of water chemistry for Ca–HCO₃ spring waters was modeled by reactions of rainwater with soil organic matter, calcite, and dolomite under oxic conditions. The Na–Cl and mixed-type springs were modeled by reactions of either rainwater or Upper Floridan aquifer water with soil organic matter, calcite, and dolomite under oxic conditions and mixed with varying proportions of saline Lower Floridan aquifer water, which represented 4–53% of the total spring discharge. Multiple-tracer data—chlorofluorocarbon CFC-113, tritium (³H), helium-3 (³He_trit), sulfur hexafluoride (SF₆)—for four Ca–HCO₃ spring waters were consistent with binary mixing curves representing water recharged during 1980 or 1990 mixing with an older (recharged before 1940) tracer-free component. Young-water mixing fractions ranged from 0.3 to 0.7. Tracer concentration data for two Na–Cl spring waters appear to be consistent with binary mixtures of 1990 water with older water recharged in 1965 or 1975. Nitrate-N concentrations are inversely related to apparent ages of spring waters, which indicated that elevated nitrate-N concentrations were likely contributed from recent recharge.The online version of the original article can be found at     

烃类组分在金属矿床的成矿理论和矿产勘查研究中的应用

很多的研究证据表明烃类组分在自然界赋存空间和范围非常广泛:如地表和近地表的各类岩石和土壤,现代海底烟囱、海槽现代活动热水区和火山喷发气体,深源的基性-超基性岩和玄武岩包裹体,甚至在碳质球粒陨石中都有烃类组分的存在.因此对烃类组分的研究不应局限于石油、天然气和煤炭等能源矿床,而应该推广到各类金属矿床及其流体的研究中来.与其他气态组分如CO2、H2S、N2、H2等相比,烃类具有组分多元化和性质稳定的特点,同时烃类各组分间的相关特征和配分规律是其地质流体演化过程(氧化-还原条件、温度、压力等环境因素)中的重要参数.为直观表现烃类组分综合特征和流体混合、叠加演化过程中烃类组分细微变化,本文提出建立烃类组分标准化背景的研究思路,探索性地将具有幔源流体特征的峨眉山玄武岩作为烃类组分的标准化背景,其意义类似于选择球粒陨石作为标准化稀土元素背景的建立.通过在云南个旧和广西大厂锡多金属矿、陕西马鞍桥金矿等多个典型金属矿床上实际应用,表明该研究方法能将各类地质体烃类组分差异性和演化的规律性得到直观体现,将单纯的烃类组分宏观异常特征归纳、发展为对烃类组分的叠加改造、配分模式以及相关特征的微观规律研究,将过去烃类组分仅作为有机质参与金属成矿的表征现象,发展成为能应用于成矿物质来源、成矿流体演化及成矿作用和规律研究的工具和手段.     

千山花岗岩地球化学特征及其成因探讨

千山花岗岩位于辽宁省鞍山地区,形成于中生代,为一由多种岩石类型组成的花岗岩套。千山花岗岩体的地球化学特征表明,其某些特殊成分含量及某些特征值同澳大利亚东南部晚泥盆世的 A 型花岗岩相似,因此,千山花岗岩具有 A 型花岗岩的特征。它是部分熔融的产物,其岩浆熔体的母岩成分大致相当于富含角闪石的中性火成岩。