再论油气与金属（非金属）矿床的相互关系

本文根据近代Ｐｂ－Ｓｒ－Ｎｄ同位素地球化学在油气研究领域的新成果，指出油气与金属（非金属）矿床的相互关系需重新审视。从卤水、火山作用对油气、金属（非金属）矿床分布的影响，认为造成油气与金属（非金属）矿床这种空间分布关系的主要原因，可能由于它们均源于深部物质，而不是上部地壳的矿源层、烃源层。深入进行这项研究，必将对矿床成因理论有新的突破，并将对矿床勘探产生重大影响。     

Variation of heavy metals in recent sediments from Piratininga Lagoon (Brazil): interpretation of geochemical data with the aid of multivariate analysis

In the last decade, the Atlantic coast of south-eastern Brazil has been affected by increasing deforestation and anthropogenic effluents. Sediments in the coastal lagoons have recorded the process of such environmental change. Thirty-seven sediment samples from three cores in Piratininga Lagoon, Rio de Janeiro, were analyzed for their major components and minor element concentrations in order to examine geochemical characteristics and the depositional environment and to investigate the variation of heavy metals of environmental concern. Two multivariate analysis methods, principal component analysis and cluster analysis, were performed on the analytical data set to help visualize the sample clusters and the element associations. On the whole, the sediment samples from each core are similar and the sample clusters corresponding to the three cores are clearly separated, as a result of the different conditions of sedimentation. Some changes in the depositional environment are recognized using the results of multivariate analysis. The enrichment of Pb, Cu, and Zn in the upper parts of cores is in agreement with increasing anthropogenic influx (pollution).     

Formation and destruction of magnetite in CO3 chondrites and other chondrite groups

Primitive CO3.00–3.1 chondrites contain ∼2-8 vol.% magnetite, minor troilite and accessory carbide and chromite; some CO3.1 chondrites have fayalite-rich veins, chondrule rims and euhedral matrix grains. All CO3.00–3.1 chondrites contain little metallic Fe-Ni (0.4–1.2 vol.%). CO3.2–3.7 chondrites contain 1–5 vol.% metallic Fe-Ni, minor troilite, accessory chromite and 0-0.6 vol.% magnetite. Magnetite is formed in primitive CO3 chondrites from metallic Fe by parent-body aqueous alteration, resulting in decreased metallic Fe-Ni and an increase in the proportion of high-Ni metal grains. The paucity or absence of magnetite in CO chondrites of subtype ≥3.2 suggests that magnetite is destroyed during thermal metamorphism; thermochemical calculations from the literature suggest that magnetite is reduced by H₂ and reacts with SiO₂ to form fayalite and secondary kamacite. Analogous processes of magnetite formation and destruction occur in other chondrite groups: (1) Primitive type-3 OC have opaque assemblages containing magnetite, carbide, Ni-rich metal and Ni-rich sulfide, but OC of subtype >3.4 contain little or no magnetite. (2) Primitive R3 chondrites and clasts (subtype ≲3.5) contain up to 6 vol.% magnetite, but most R chondrites contain no magnetite. The principal exception is magnetite with 9–20 wt.% Cr₂O₃ in a few R4-6 chondrites. Magnetite grains with high Cr₂O₃ behave like chromite and are more stable under reducing conditions. (3) CK chondrites average ∼4 vol.% magnetite with substantial Cr₂O₃ (up to ∼15 wt.%); these magnetite grains also are stable against reduction during metamorphism. (4) The modal abundance of magnetite decreases with metamorphic grade in CV3 chondrites. (5) Chromite occurs instead of magnetite in those rare samples classified CR6, CR7 and CV7.     

Chemical Characterization of Biosolids from Three Spanish WWTPs: Transfer of Organics and Metallic Pollution from Urban Wastewater to Biosolids

The production of biosolids in three Spanish wastewater treatment plants (WWTPs) has been investigated. Biosolids produced from the treatment of urban wastewater in Spain are usually intended for agricultural use. The reliable production of biosolids mainly depends on both the quantity of suspended solids and the organic load influent to the treatment systems. The quality of the generated biosolids was independent of both the amount of treated water and the treatment process applied, with 20 to 25% dried matter, and 60 to 75%, 7% and 4% of organic matter, N and P, respectively, of the total matter. The biosolids contained ca. 11 to 19 g/kg of total metals in the dry matter, with Fe, Zn, Cu and Mn representing 97% of all of the metals present, and Hg being the minority metal. Such biosolids had the ability to concentrate the organic matter and metals from the wastewater up to 417 and 869 times, respectively, and thus, can be used in agricultural practice.     

SIMULTANEOUS ANALYSIS OF Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ),Zn(Ⅱ)AND Cd(Ⅱ)BY SPECTROPHOTOMETRY AND THE KALMAN FILTER

This paper describes the simultaneous determination of cobalt,nickel,copper,zinc and cadmium byspectrophotometry and the Kalman filter method.Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ),Zn(Ⅱ)and Cd(Ⅱ)react with 5-bromo-2-(2-pyridylazo)-5-diethylaminophenol(5-Br-PADAP)in the presence of cationic surfactant cetylpyridinium bromide(CPB)to form five different coloured ternary complexes.The absorption curves ofthese complexes overlap severely in the scanning range 500-620 nm.The Kalman filter algorithm issuccessfully applied to resolve the overlapped absorption curves and therefore makes the simultaneousdetermination of these metallic ions possible without tedious pretreatment.The proposed method isapplied to analyse the titled elements in synthetic samples and in environmental samples such as hair,fingernail and river water samples with satisfactory results.     

南秦岭柞水-山阳矿集区小河口矽卡岩型铜矿床矿物化学及其成矿意义

秦岭造山带燕山期斑岩-矽卡岩型铜矿床因过去发现的数量有限,限制了对区内铜矿床成矿机制的深入研究。小河口铜矿床是南秦岭柞水-山阳矿集区内的典型矽卡岩型铜矿床,矿体产于燕山期花岗闪长玢岩与泥盆系桐峪寺组地层接触处的矽卡岩带内。成矿作用划分为4个阶段:Ⅰ干矽卡岩阶段、Ⅱ湿矽卡岩-氧化物阶段、Ⅲ石英-硫化物阶段和Ⅳ碳酸盐-石英阶段。本文在对该矿床矽卡岩矿物(石榴子石和辉石)和金属矿物(磁铁矿和硫化物)详细的岩(矿)相学观察基础上,针对这些矿物进行系统的电子探针成分分析,来示踪矽卡岩的成因和形成环境,讨论成矿元素的沉淀富集过程。研究表明,小河口铜矿床为典型的接触交代成因钙质矽卡岩型矿床。干矽卡岩矿化阶段从早到晚依次形成钙铝榴石(Adr_(24-31)Gr_(68-74))、钙铝榴石组分-钙铁榴石组分交替系列(Adr_(26-68)Gr_(31-72))和透辉石(Di_(73-91)Hd_(8-24))-纯钙铁榴石(Adr_(68-100)Gr_(0-30))。伴随着岩浆结晶分异,初始岩浆-热液流体与灰岩发生接触交代作用首先形成无环带钙铝榴石(Grt-a)矽卡岩,此时成岩环境为低氧逸度、酸性还原环境,不利于矽卡岩铁、铜矿化的形成;成矿流体不断从岩浆中出溶并发生多次沸腾,引起残留热液的氧化还原状态发生周期性变化,成矿热液由酸性逐渐向弱碱性演化,进而导致Fe~(3+)和Al~(3+)活度的变化,在振荡的物理化学环境中形成了钙铝榴石-钙铁榴石组分交替生长的宽环带石榴子石(Grt-c)矽卡岩;随着岩浆演化和流体作用的扩大,成矿体系处于较稳定的碱性和高氧逸度环境,Fe和Al的过饱和程度此消彼长,形成了透辉石-密集振荡环带钙铁榴石(Grt-b和Grt-d)矽卡岩。成矿流体演化进入湿矽卡岩-氧化物阶段后,富含挥发分的热液活动起主导作用,沸腾作用将H~+和CO_2分离进入气相,导致流体体系碱性和氧逸度程度进一步升高,进而形成磁铁矿和镜铁矿大量沉淀富集。石英-硫化物阶段,随着温度和氧逸度骤减导致黄铁矿、磁黄铁矿和黄铜矿等硫化物发生沉淀,并以石英-硫化物脉的形式充填于构造裂隙或矽卡岩内。