中国煤中硫的地球化学研究

燃烧过程中,煤中硫会以硫氧化物等形式释放出来,污染大气以至形成酸雨,对环境造成极大的影响。本文在对中国煤中硫全面分析的基础上．总结并分析了中国煤中硫在不同地区、不同煤层和不同形成环境中的含量与分布规律,阐述煤中硫形成的地质成因和影响因素．以及育机硫、无机硫和元素硫的赋存状态．概述了煤利用过程中硫的转化机理及其对环境的影响．提出了对煤中硫的研究趋势和今后研究方向与热点问题。     

Isotopic Geochemistry of Chinese Fluorite Deposits

China is one of the richest countries in the world in terms of fluorite resources. On the basis of host rocks and mineralization patterns, the fluorite deposits in China have been classified into three types: (1) those occurring in Mesozoic volcanic regions, mainly consisting of veinfilling deposits of the quartz-fluorite association (Type I); (2) those occurring in granite areas, chiefly belonging to veinfilling deposits of the quartz-fluorite association or veinfilling or altered-rock deposits associated with Pb, Zn, W, Sn, etc. (Type II); and (3) those occurring in carbonate rocks as bedded deposits of quartz-fluorite, sulfide-fluorite, and quartz-barite-calcite-fluorite assemblages (Type III).

This paper summarizes the characteristics of fluorite deposits in China on the basis of strontium-, hydrogen-, and oxygen-isotopic and geochronological data, as well as geological investigations of deposits from 22 mining districts. δ¹⁸O and δD values of ore-forming fluids are ?10.2 to +3.7‰ and ?77.9 to 41.0‰, respectively, for Type-I deposits, ?13.1 to ?4.9‰ and ?65.5 to ?41.7‰ for Type-II deposits, and -5.6 to +4.3‰ and ?80 to ?29‰ for Type-Ill deposits. Study of the isotopic water-rock exchange indicates that the mineralizing fluids for these types of deposits have been derived mostly from circulating geothermal water that originated from Mesozoic meteoric water. The differences in the isotopic characteristics of hydrothermal systems for various types of deposits depend mainly on isotopic exchange between water and rocks, the water/rock values being 0.05 to 2.0 for Type-I deposits, generally more than 2.0 for Type-II deposits, and 0.5 to 3.0 for Type-Ill deposits.

The ore-forming ages for Type-I and Type-II deposits are roughly separated into three groups—230 to 180 Ma, 120 Ma, and 90 to 60 Ma. These ages successively decrease from northwestern China to southeastern coastal areas.

⁸⁷Sr/⁸⁶Sr values of 0.7306 to 0.7710 (mean 0.7513) from fluorite in the early stage (main mineralization) for Type-I deposits are higher than those from host rocks (0.7081 to 0.7260) during the mineralizing event, and mostly fall in the range of ⁸⁷Sr/⁸⁶Sr values from basement metamorphic rocks (from 0.7455 to 0.9094) during the epoch of mineralization. But the ⁸⁷Sr/⁸⁶Sr values of 0.7102 to 0.7137 (mean 0.7122) for late-stage fluorite and calcite are similar to those of surrounding host rocks. This indicates that the mineralizing materials of early stages in the formation of deposits (Type-I) originated mostly from Precambrian basement metamorphic rocks; those of later stages (Type II) were derived chiefly from host rocks. Type-II and Type-Ill deposits from different mining areas exhibit great variations in ⁸⁷Sr/⁸⁶Sr values, but are quite similar to their host rocks, indicating that the mineralizing materials in Type-II and Type-Ill deposits were derived chiefly from their host rocks.     

The Geochemistry of Scapolite Part II. Trace Elements, Petrology, and General Geochemistry

Fifty scapolites have been analysed spectrographically for numerouselements. Average concentrations (p.p.m.) were as follows: B25, Be 9-3, Ga 33, Ti 82, Li 56, Cu 4-4, Zr 59, Mn 57, Sr 1,800,Pb 45, Ba 120, Rb 20. The following were seldom or never detected:Cr, Ni, Co, Mo, Sn, V, Sc, Ag, Y, La. The major elements Ca,Na, K were also determined. The distribution of the trace elementscan be explained by isomorphous substitution, but no detailedcorrelation of trace elements with each other or with majorelements was found. Refractive indices were determined and the relation betweenaverage index and per cent Me was examined: correlation waspoor, which may in part be attributed to analytical error. Examination of scapolite parageneses shows that scapolite characteristicallyoccurs in the upper amphibolite facies or the pyroxene hornfelsfacies: it is not restricted to these and may occur in any faciesfrom zeolitic to granulitic and in any hornfels facies. Theelements generally concentrated in scapolite include Ca, Na,C, Cl, S, H, B, Be, Li, Sr, Pb. The presence of C, Cl, S, Htestify to genesis in the presence of high partial pressureof CO₂, Cl₂, SO₃, H₂O (or related compounds), that is in pneumatolytic,pegmatitic, or hydrothermal environments. The concentrationof B, Be, Li can also be attributed to these conditions. The source of the elements concentrated in scapolite must inpart be common rocks. In a limited contact zone, the nearbymagma supplied some elements, but where regional scapolitizationhas taken place the presence of magma is less clear. Many commonrocks or rock series contain all the necessary constituents,but some particular conjunction of conditions is necessary forscapolite to form, or it would be more common.     

The Geochemistry of Scapolite: Part II. Trace Elements, Petrology, and General Geochemistry

Fifty scapolites have been analysed spectrographically for numerouselements. Average concentrations (p.p.m.) were as follows: B25, Be 9–3, Ga 33, Ti 82, Li 56, Cu 4–4, Zr 59,Mn 57, Sr 1,800, Pb 45, Ba 120, Rb 20. The following were seldomor never detected: Cr, Ni, Co, Mo, Sn, V, Sc, Ag, Y, La. Themajor elements Ca, Na, K were also determined. The distributionof the trace elements can be explained by isomorphous substitution,but no detailed correlation of trace elements with each otheror with major elements was found. Refractive indices were determined and the relation betweenaverage index and per cent Me was examined: correlation waspoor, which may in part be attributed to analytical error. Examination of scapolite parageneses shows that scapolite characteristicallyoccurs in the upper amphibolite facies or the pyroxene hornfelsfacies: it is not restricted to these and may occur in any faciesfrom zeolitic to granulitic and in any hornfels facies. Theelements generally concentrated in scapolite include Ca, Na,C, Cl, S, H, B, Be, Li, Sr, Pb. The presence of C, Cl, S, Htestify to genesis in the presence of high partial pressureof CO₂, Cl₂, SO₃, H₂O (or related compounds), that is in pneumatolytic,pegmatitic, or hydrothermal environments. The concentrationof B, Be, Li can also be attributed to these conditions. The source of the elements concentrated in scapolite must inpart be common rocks. In a limited contact zone, the nearbymagma supplied some elements, but where regional scapolitizationhas taken place the presence of magma is less clear. Many commonrocks or rock series contain all the necessary constituents,but some particular conjunction of conditions is necessary forscapolite to form, or it would be more common.     

中国煤中硒的环境地球化学

硒是煤中易挥发元素之一。伴随煤炭的开采、利用,煤中硒可能进入环境并引起环境质量的变化,影响生态环境和人体健康。本文在全面综合国内外研究文献的基础上,分析了中国煤中硒在不同省份、不同成煤时代中的含量及分布规律,总结了硒在煤中的赋存状态、形成机理和影响因素,概括了煤在燃烧和淋溶过程中硒的迁移转化及其环境影响,指出中国煤中硒的含量在不同煤田、不同成煤时代及不同变质程度的煤中,含量差别较大,全国平均值约为5.60 mg/kg。     

中国矿物岩石地球化学学会第九届侯德封矿物岩石地球化学青年科学家奖评选公告

20 0 2年 6月 2日 ,在我会第五届理事会理事长、第四届侯德封矿物岩石地球化学青年科学家奖评选委员会主任欧阳自远院士的主持下 ,顺利进行了第九届侯德封矿物岩石地球化学青年科学家奖的评选。本次共评选出 6名获奖人。现将评选结果公告如下 (以姓氏笔划为序 )。韦刚健　男 ,196 8年 6月生 ,中国科学院广州地球化学研究所副研究员 ,博士 ;请奖项目 :海洋地球化学及其气候环境演变记录研究获奖人主要学术成就 :1)率先在国内开展高分辨率珊瑚古气候重建的研究 ,首先成功建立了高精度的热电离质谱 (ＴＩＭＳ)Ｕ Ｔｈ定年方法。该方法使精确测…     

The Geochemistry of Lake Joyce, McMurdo Dry Valleys, Antarctica

Lake Joyce is one of the least studied lakes of the McMurdo Dry Valleys. Similar to other lakes in this region, Lake Joyce is a closed-basin, permanently ice-covered, meromictic lake. We present here a detailed investigation of major ions, nutrients, and dissolved trace elements for Lake Joyce. Specifically, we investigate the role of iron and manganese oxides and hydrous oxides in trace metal cycling.Lake Joyce is characterized by fresh, oxic waters overlying an anoxic brine, primarily Na–Cl. Surface waters have a maximum nitrate concentration of 26M with a molar dissolved inorganic nitrogen to phosphorus ratio of 477. The supply of nitrogen is attributed to atmospheric deposition, possibly from polar stratospheric clouds. Dissolved phosphorus is scavenged by hydrous iron oxides. The pH is highest (10.15) just beneath the 7-m thick ice cover and decreases to a minimum of 7.29 in the redox transition zone. Dissolved Al exceeds 8M in surface waters, and appears to be controlled by equilibrium with gibbsite. In contrast, concentrations of other trace elements in surface waters are quite low (e.g., 5.4nM Cu, 0.19nM Co, <20pM La). Dissolved Fe, Mn, Ni and Cd were below our detection limits of 13 nM, 1. 8 nM, 4.7 nM and 15pM (respectively) in surface waters. There was a 6-m vertical separation in the onset of Mn and Fe reduction, with dissolved Mn appearing higher in the water column than Fe. Based on thermodynamic calculations, dissolved Mn appears to be controlled by equilibrium with hausmannite (Mn3O4). Co tracks the Mn profile closely, suggesting Co(III) is bound in the lattice of Mn oxides, whereas the Ce profile is similar, yet the Ce anomaly suggests oxidative scavenging of Ce. Release of Cu, Ni, Cd and trivalent REE appears to be controlled by pH-induced desorption from Fe and Mn oxides, although Cu (and perhaps Ni) may be scavenged by organic matter in surface waters.     

铀有机地球化学研究进展

与铀矿有密切关系的有机质主要是腐殖酸（HAs)、富里酸（FAs)、微生物及细菌。腐殖酸与铀酰存在着强烈的吸附、络合及还原作用关系。微生物和细菌在铀矿形成过程中也起到一定的作用。在研究手段上包括试验、计算、热解分析、X－线分析、裂变径迹分析、电子探针、红外光谱、紫外光谱、荧光光谱、顺磁共振、色谱质谱联用等方法。     

东天山四顶黑山层状岩体岩石地球化学特征

位于东天山黄山岩带最东端的四顶黑山镁铁质-超镁铁质层状杂岩体规模较大,呈北东向展布,可分为南、北2个岩体。主要岩石类型有单辉橄榄岩、橄榄辉石岩、橄榄苏长辉长岩、橄榄辉长岩、辉石角闪岩、辉长岩和角闪辉长岩,超镁铁岩相常与辉长岩相呈韵律互层。主量元素化学组成主要属拉斑玄武岩系列。岩石稀土元素配分曲线呈平坦型以及Eu的正异常,普遍富集大离子亲石元素(Rb、Ba、U),显示明显的Sr正异常以及Nb、Ta的亏损。通过橄榄石最高的Fo值(79.6)估算出母岩浆中MgO和FeO含量分别为6.23%和6.60%。岩浆在演化过程中发生了橄榄石、斜方辉石、单斜辉石、斜长石的分离结晶/堆晶作用以及较弱的上地壳同化混染作用。岩石高的(La/Yb)N值1.550和1.744值表明岩浆源区的深度可能大于90km;Th/U值特征以及Th/Yb-Nb/Yb和La/Ba-La/Nb图解表明,四顶黑山岩体的岩浆源区可能为受俯冲作用改造的岩石圈地幔。     

Geochemistry of the Kupferschiefer,Poland

Cu, Pb and Zn are the main metals occurring in sulfides in the Kupferschiefer. They are arranged in the three distinct zones around »Rote Fäule«, in the order Cu, Pb and Zn. Copper zones are enriched in transition metals, i.e. Ag, Ni, Co, V and Mo ranging from 600 to 1500 ppm; they are concentrated especially in the bottom part of black shale. Re is associated with Mo; the Re: Mo ratio in Cu-, Pb- and K-castaingites is about 170.In copper zones, near the contact with lead zones, Au, platinum group metals (PGM) and U are concentrated, ranging from traces to several hundred ppm. The main mechanism of concentration of transition metals was catalytic autooxidation and dehydrogenation of organic matter.The noble metals form either independent minerals or are present in organic matter and thucholite. In the lead zones, at the contact with Cu zones, an increased content of Ag (100–1500) and Hg (5–800) ppm is present. The average Hg content for the black shale of the zone is 61 ppm.A natural gas, exploited from the Rotliegendes beneath the Kupferschiefer, carries, in aerosols, significant amount of Pb, Cu, Mn, Fe, Ag and Hg. This suggests the Rotliegendes as a pathway or as a source of metals for the Kupferschiefer. The presence of K-castaingite intergrown with silvinite (KCl) may suggest K-dominated brines as the mineralizing fluids.

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Zusammenfassung Die häufigsten Metalle, die in den Sulfiden des Kupferschiefers vorkommen, sind Kupfer, Blei und Zink. Diese Metalle sind in der Reihenfolge Cu-Pb-Zn an drei bestimmte Zonen um die »Rote Fäule« gebunden.Die Kupfer-führenden Zonen sind reich an Übergangsmetallen wie Ag, Ni, Co, V und Mo, deren Konzentrationen zwischen 600 und 1500 ppm schwanken und die hauptsächlich in bodennahen Bereichen des Schwarzschiefers angereichert sind. Dabei tritt Re in Verbindung mit Mo auf und das Re-Mo Verhältnis in Cu-, Pb- und K-Castaingiten ist ungefähr 170.Gold, Platin-Gruppen-Metalle (PGM) und Uran, deren Konzentrationen zwischen geringen Spuren und mehreren 100 ppm liegen, findet man in Kupfer-führenden Schichten in der Nähe von Kontakten zu Blei-führenden Zonen. Katalytische Autooxidation und Dehydrogenisierung organischen Materials sind die dominierenden Mechanismen, die die Anreicherung der Übergangsmetalle steuern. Die Metalle liegen als Minerale oder gebunden an organische Substanz und Thucholit vor.In den Kontaktbereichen der Blei- und Kupferzonen findet man erhöhte Werte von Ag (100–1500 ppm) und Hg (5–800 ppm). Der Durchschnittswert für Hg im Schwarzschiefer beträgt 61 ppm.Ein natürliches Gas, das aus dem den Kupferschiefer unterlagernden Rotliegenden gefördert wird, enthält als Aerosole bedeutende Mengen an Pb, Cu, Mn, Fe, Ag und Hg. Somit ist es wahrscheinlich, daß das Rotliegende entweder als Quelle der Metalle des Kupferschiefers oder zumindest als Durchgangsstation der Metallführenden Lösungen anzusehen ist. Das Vorkommen von K-Castaingit-Verwachsungen mit Silvinit (KCI) spricht für K-reiche Solen als mineralisierende Lösungen.

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Résumé Le Cu, le Pb et le Zn sont les métaux principaux des sulfures de la formation des Kupferschiefer. Ils sont distribués autour de la «Rote Fäule» en trois zones distinctes, dans l'ordre: Cu - Pb - Zn.Les zones à Cu sont enrichies en métaux de transition (Ni, Co, V et Mo) quiy présentent des teneurs de 600 à 1500 ppm; ces métaux sont concentrés spécialement dans les parties inférieures des schistes noirs. Le Re est associé au Mo, avec un rapport Re/Mo de l'ordre de 1,70 dans les castaingites à Cu, Pb et K.Dans les zones à Cu, près du contact avec les zones à Pb, on observe une concentration de Au, de U et des métaux du groupe du Pt, avec des teneurs qui vont des traces à quelques centaines de ppm. Le mécanisme principal de la concentration des métaux de transition a été l'auto-oxydation et la déshydrogénation catalytiques de la matière organique. Les métaux nobles sont sous la forme de minéraux indépendants, ou sont contenus dans la matière organique et la tucholite.Dans les zones à Pb, il existe une concentration en Ag (100–1500 ppm) et en Hg (5–800 ppm) au contact avec les zones à Cu. La teneur moyenne en Hg des schistes noirs est de 61 ppm.Un gaz naturel, exploité à partir des Rotliegende situés sous les Kupferschiefer, renferme, sous forme d'aérosols, des quantités appréciables de Pb, Cu, Mn, Fe, Ag et Hg. Les Rotliegende pourraient donc être soit la source, soit le chenal des métaux contenus dans les Kupferschiefer. La présence d'intercroissances de castaingite potassique et de sylvinite (KC1) suggère que les fluides minéralisants ont pu être des solutions potassiques.

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, . «Rote Fäule»., , , .: Ag, Ni, Co, V , 600 1500 ppm; . Re , Re/Mo , 170., , , , , . . , . (100–1500 ppm) Hg (5–800 ppm). 61 m. , , , , , . , , , , - , « » , . KCl , .

     

有机地球化学指标的分析

有机地球化学的指标经过近几十年的研究,已能较好地指导油气勘探工作。通过对未熟—低熟烃源岩及原油与成熟烃源岩及原油的有机地球化学指标的比较,着重论述了未熟—低熟油、源中可用的指标系列及内涵,指出成熟度方面甾烷C2920Rββ/(αα ββ)、αααC2920S/(20S 20R)及βα-莫烷/αβ-藿烷和ββ-藿烷等是比较可靠的地球化学参数;在生源方面非环状类异戊二烯化合物、三环萜烷和四环萜烷系列等是可靠的标志物;形成环境方面β-胡萝卜烷及重排甾烷/规则甾烷等都是重要的指标。     

Geochemistry Of The GuaxupÉ Granulites, Minas Gerais, Brazil

Geochemical data for granulite terrain are presented in the northernmost portion of the Guaxupé Massif, at Mantiqueira Province, SE Brazil. Several types of granulites are recognized in the area: basic, intermediate and acid granulite. Major and trace elements (including REE) point to only one magma source for these granulites generated at different times. Geochemical data point to plagioclase and apatite fractionation as the responsable by the REE behaviour in intermediate and more basic rocks. Overall composition of the Guaxupé Granulites is similar to average described worldwide in the literature to the lower crust.