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1.
为了探讨煤中微量元素的赋存状态和地质成因,本文运用电离耦合等离子体质谱(ICP-MS)、电离耦合等离子体原子发射光谱(ICP-AES)、X射线荧光光谱(XRF)、冷原子吸收光谱(CV-AAS)、离子选择性电极法(ISE)、逐级化学提取试验(SCEE)等,研究了重庆长河碥矿晚三叠世须家河组2号煤层中微量元素的含量、赋存特征及其影响因素.发现该煤层中As(12.9 μg/g)、Cu(125 μg/g)、Cr(72 μg/g)、Ni(63 μg/g)、Pb(111 μg/g)等元素富集;逐级化学提取结果显示,煤层中Pb主要赋存在低温热液成因的黄铁矿脉中;Cr主要存在于粘土矿物中,Cr可能与陆源碎屑供给有关;Cu不仅与粘土矿物有关,也与煤中黄铁矿有关.表明低温热液流体和陆源碎屑供给对该煤中主要微量有害元素的含量和赋存特征起了决定作用.  相似文献   

2.
运用电感耦合等离子体质谱(ICP-MS)、X射线荧光光谱(XRF)、带能谱仪的扫描电镜(SEM-EDX)、逐级化学提取(SCEP)和光学显微镜等方法,对贵州大方煤田11号煤层的地球化学和矿物学进行了研究。结果表明,大方煤田11号煤层中有高含量的脉状石英(11.4%)和脉状铁白云石(10.2%),铁白云石周边常被针铁矿所包裹,在脉状石英中发现有热液成因的黄铜矿、闪锌矿和硒方铅矿,此外,还有少量高岭石充填在脉中,这7种矿物常常同脉共存。脉状石英和脉状铁白云石分别来源于硅质和富铁的钙质低温热液流体,形成温度分别为180℃和85℃。脉状石英早于脉状铁白云石形成。根据Ca/Sr和Fe/Mn值,确定出铁白云石的形成至少经历了3个时期。这7种矿物按照从早到晚的生成顺序为硫化物、石英、高岭石、铁白云石和针铁矿。铁白云石是煤中Mn、Cu、Ni、Pb和Zn富集的主要原因,这5种微量元素的含量分别为0.09%、74.0μg/g、33.6μg/g、185μg/g和289μg/g。脉状石英是煤中铂族元素Pd、Pt和Ir的主要载体,它们在煤中的含量分别为1.57μg/g、0.15μg/g和0.007μg/g。另外,黄铜矿、闪锌矿和硒方铅矿亦是11号煤层中Cu、Zn和Pb的重要载体。  相似文献   

3.
锂(Li)是一种重要的金属能源,近年来全球锂的需求持续增长。我国煤伴生型锂矿床的发现证明煤矿可能成为锂资源的潜在来源。以贵州普安矿区20号煤为研究对象,采用工业分析、镜下鉴定、X射线荧光光谱(XRF)、电感耦合等离子体质谱(ICP-MS)、激光剥蚀?电感耦合等离子体质谱(LA-ICP-MS)等方法,分析原煤及浮沉实验获得的密度分级试样的基本性质、矿物组成、元素组成及煤中Li的赋存特征。结果表明,原煤中Li含量达134.09 μg/g,在6个密度级样品中,Li含量随煤样密度级的增加而增加(>1.8 g/cm3密度级样品中Li含量最高为212 μg/g),重力分选可使煤中Li得到一定程度的预富集。原煤主要矿物组分包括黏土矿物、黄铁矿、方解石、石英等,基于Li与Al、Si等的相关性以及矿物微区元素含量(LA-ICP-MS)等分析,推测Li可能主要以吸附态赋存于黏土矿物中。逐级化学提取实验结果表明,煤中Li的赋存特征为水溶态(20.96%)、离子交换态(32.90%)、硅酸盐/铝硅酸盐态(22.80%)、碳酸盐/磷酸盐态(10.81%)、二硫化物态(3.92%)和残渣/有机态(2.58%),说明通过离子交换法可以从煤矸石中回收Li。该研究结果为下一步分离提取煤中Li提供了一定理论指导。   相似文献   

4.
运用电离耦合等离子体质谱(ICP-MS)和逐级化学提取(SCEE)的方法测定了云南砚山晚二叠世煤中金属元素的含量,发现煤中高度富集V、Cr、Mo和U,含量分别为621 μg/g、315 μg/g、198 μg/g和167 μg/g.逐级化学提取结果表明,这4种元素主要赋存在有机质和硅铝化合物中,反映其是在泥炭聚集期间或成岩作用早期进入到泥炭沼泽而富集的.  相似文献   

5.
运用仪器中子活化分析、电离耦合等离子体原子发射光谱、X射线荧光光谱、X射线衍射分析、带能谱仪的扫描电镜和逐级化学提取试验研究了贵州织金煤矿区上二叠统含煤岩系30号煤层中伴生元素的含量、赋存状态和矿物特征。结果表明,煤层中有高含量的脉状石英(9．4％),其δ^30Si、δ^18O值分别为0．6％。和15.4‰,表明脉状石英来源于硅质低温热液流体;脉状石英是煤中高含量Fe(2．31％)、Cu(356μg／g)、U(8μg／g)、Pd(2．1μg／g)、Pt(2．43μg／g)和Ir(0．006μg／g)的主要载体。  相似文献   

6.
黔西晴隆矿区晚二叠世煤地球化学变异的地质成因   总被引：3，自引：0，他引：3  
李大华  唐跃刚 《地质论评》2005,51(2):163-168
运用仪器中子活化分析(INAA)、电离耦合等离子体质谱(ICP—MS)、电离耦合等离子体原子发射光谱(ICP—AES)、X射线荧光光谱(XRF)、冷原子吸收光谱(CVAAS)、离子选择性电极法(ISE)、逐级化学提取试验(SCEE)等,结合带能谱仪的扫描电镜(SEMEDX)和MPV—Ⅲ显微镜下观察的煤岩学特征的分析,对贵州晴隆矿区上二叠统含煤岩系8号煤层中微量元素的含量和赋存特征及其影响因素进行了研究。发现该煤层中Cu(263.4μg／g)、Cr(154．2μg／g)、Hg(0．86／μg／g)、Mo(82．47μg／g)、Ni(63．3μg／g)、Pb(200．4／μg／g)、Se(4．25／μg／g)、U(154．8／μg／g)、Zn(214．6／μg／g)和Zr(754．3μg／g)等元素异常富集;而As和F的含量不高,其含量分别为1．58／μg／g和83．4μg／g。逐级化学提取结果显示,该煤层中Hg、Mo、Ni、Pb、Se和Zn元素主要赋存在低温热液成因的黄铁矿脉中;Cr、U和Zr主要存在于粘土矿物中,其中Cr和Zr可能与康滇古陆陆源碎屑供给有关;Cu不仅与粘土矿物有关,而且也和煤中黄铁矿有关。表明低温热液流体和陆源碎屑供给对该煤中主要微量有害元素的含量和赋存特征起了决定作用。  相似文献   

7.
宁武煤田平朔矿区9号煤中锂的富集机理   总被引：1，自引：0，他引：1  
刘帮军 《地质与勘探》2014,50(6):1070-1075
从宁武煤田平朔矿区的9号煤中共采了58个煤样,通过光学显微镜、逐级化学提取、SEM-EDX分析、X射线粉末衍射和ICP-MS技术对这些样品进行分析。结果表明9号煤中Li的平均含量达到152 mg/kg,9号煤的点储量为36.7亿吨,Li O2的量达119.5万吨,也就是说煤层中锂的储量约为55.8万吨;逐级化学提取过程的结果表明,Li的富集主要与无机物有关,只有约5.5%的锂具有有机亲和力,这些无机矿物是高岭石、勃姆石、绿泥石族矿物、石英、方解石、黄铁矿以及无定形粘土状矿物等,在含锂煤层中,锂可能被粘土矿物吸附;根据古地理研究,9号煤中锂的最初来源可能是阴山古陆,盆地北部本溪组中的铝土矿可能是锂的直接来源。  相似文献   

8.
煤层能在特定的地质条件下富集多种关键金属元素,形成具有综合利用价值的“煤型关键金属矿床”,随着煤中共伴生金属元素提取技术日益成熟,研究煤中金属元素的富集与分布特征、查明具有成矿潜力的富集区具有十分重要的资源意义。本研究基于近20年以来前人发表的有关贵州煤地球化学的研究成果及作者自测数据,统计了贵州省23个主要产煤县(市)的1002个样品数据,揭示了贵州煤中Li、Zr、Hf、Nb、Ta、U和稀土元素(REY,即REE+Y)等关键金属元素的总体分布富集特征。研究表明,贵州煤中Li、Zr、Nb、REY等关键金属元素较为富集并具有共伴生成矿潜力的区域为黔北煤田和黔西南兴义煤田两个区域。其中,金沙、桐梓、普安等地煤中Li平均含量换算为灰基Li2O分别为1254μg/g、1214μg/g和724.4μg/g,务川和正安煤种Zr平均含量换算为灰基ZrO2分别为4749μg/g和4168μg/g,务川煤中Nb平均含量换算为灰基Nb2O5为484.4μg/g,金沙、桐梓、务川及凯里煤中REY含量换算为灰基稀土氧化物R...  相似文献   

9.
华北与黔西地区晚古生代煤层中铂族元素赋存状态及来源   总被引：9，自引：2，他引：9  
运用电离耦合等离子体质谱仪(ICP-MS)对中国华北和黔西地区晚古生代煤系中54个样品的铂族元素(PGEs)进行了分析。分析结果表明,煤中铂族元素主要是通过岩浆热液活动、低温热液流体、同沉积火山灰、陆源碎屑输入和海水等诸种地质作用形成的,前3种作用是造成煤中铂族元素异常的主要原因。低含量的铂族元素(正常背景值)主要来源于硅质陆源区,煤中铂族元素的背景值为:Ru=0.005μg/g,Rh=0.014μg/g,Pd=0.181μg/g,Ir=0.001μg/g,Pt=0.037μg/g。煤中铂族元素以Pt-Pd分配模式为特征,并且Pd>Pt,Pd>>Ru、Rh、Ir,其中Pd在煤中的背景值约为地壳平均值的18倍。Pd、Pt与煤灰分呈正相关,表现出它与无机矿物的亲和性。  相似文献   

10.
丁帅帅  郑刘根  程桦 《岩矿测试》2015,34(6):629-635
煤矸石是我国堆存量最大的工业固体废物,本文应用电感耦合等离子体发射光谱法、逐级化学提取法和相关性分析研究了淮北临涣矿区低硫煤矸石中10种微量元素的含量及赋存状态,并运用风险评价指数法评价其环境效应。结果表明,低硫煤矸石中Ba、Co、Cr、Mn、Ni、Pb、V含量均高于淮北煤和中国煤均值,Mn、V的富集系数大于1,有一定迁移风险。微量元素主要以残渣态和铁锰氧化物结合态存在,两者质量分数之和为68.87%~92.93%,其中Cd、Co、Cr、Cu、Ni、Pb、Zn赋存于硫化物矿物中,V赋存于黏土矿物中,Mn赋存于碳酸盐矿物和硫化物矿物中。10种微量元素对环境的危害性大小为:MnZnNiPbCdCuBaVCrCo,表明低硫煤矸石堆存过程中活性态Mn对生态环境造成危害的可能性最大,由Mn可能引起的煤矸石山周边地区土壤及水体污染应当重视。  相似文献   

11.
ＩＮＴＲＯＤＵＣＴＩＯＮＬｏｗｅｒＣａｍｂｒｉａｎｂｌａｃｋｒｏｃｋｓｅｒｉｅｓｅｘｉｓｔｓｂｒｏａｄｌｙｉｎｍｏｒｅｔｈａｎ１０ｐｒｏｖｉｎｃｅｓｉｎＳｏｕｔｈＣｈｉｎａ（Ｃｈｅｎｅｔａｌ．,１９９０）．Ｔｈｅｂｏｔｏｍｏｆｔｈｅｓｅｒｉｅｓｓｐｏ...  相似文献   

12.
The emission of platinum group elements (PGE) from automobile catalytic converters has led to enrichment of PGE in road dusts and roadside soils in urban areas that are well above the natural background levels. This paper evaluates the source of contamination of all the PGE and Au in road dusts and roadside soils in the Pearl River Delta region, including three major cities, Shenzhen, Guangzhou and Hong Kong, South China. Samples were digested using Carius tube and analyzed by isotope dilution ICP-MS; Os was separated by distillation and other PGE by Te-coprecipitation. All samples have elevated PGE concentrations above the background values of uncontaminated soils and contain higher Pt, Pd and Rh than other PGE. The maximum values are 181 ng/g Pt, 514 ng/g Pd, 53 ng/g Rh and 1345 ng/g Au. There are clear positive correlations between Pt and Pd, Pt and Rh, and Pd and Rh, indicating that the main emitted of PGE from automobile catalyst are Pt, Pd and Rh. High concentrations of Au were also found in road dust samples from Hong Kong and Shenzhen. Dust samples with higher Os contents have lower 187Os/188Os ratios. Samples from Hong Kong show relatively high Pt/Rh ratios. Positive correlations between Pt and Ru, and Pt and Ir were found in Shenzhen and Hong Kong, but only positive correlations between Pt and Ir were found in Guangzhou. These different characteristics reflect different automobile catalytic systems used in Hong Kong and mainland China.  相似文献   

13.
Twenty five coal samples from the Late Permian coal-bearing strata in Weining, Nayong, and Zhijin, western Guizhou Province, SW, China, were analyzed for platinum group elements (PGEs). The coal ashes were digested by the Carius tube technique and accurately measured by isotope dilution-inductively coupled plasma mass spectrometry (ID-ICP-MS) for all PGEs. The results are much lower than the previous reported values. Our study suggested that the previously reported PGE values are incorrect and may due to the polyatomic interferences in ICP-MS measurements. In our study, samples from the Weining coalfield have the lowest PGE contents (from 0.019 Ir to 0.42 ng/g Pd), which represent the PGE background value in coal in western Guizhou province. Some of the coals have Pt and Pd contents about 20-times higher than the background value, indicating PGEs are concentrated. We also reported new and reliable PGE data and background value of coal in western Guizhou province, SW, China, and suggested to rework the PGE background values of Chinese coals.  相似文献   

14.
The concentrations of Rh, Au and other highly siderophile elements (HSE: Re, Os, Ir, Ru, Pt, Rh, Pd and Au), and 187Os/188Os isotope ratios have been determined for samples from peridotite massifs and xenoliths in order to further constrain HSE abundances in the Earth's mantle and to place constraints on the distributions processes accounting for observed HSE variations between fertile and depleted mantle lithologies. Concentrations of Re, Os, Ir, Ru, Pt and Pd were determined by isotope dilution ICP-MS and N-TIMS. The monoisotopic elements Rh and Au were quantified by standardization relative to the concentrations of Ru and Ir, respectively, and were determined from the same digestion aliquot as other HSE. The measurement precision of the concentration data under intermediate precision conditions, as inferred from repeated analyses of 2 g test portions of powdered samples, is estimated to be better than 10% for Rh and better than 15% for Au (1 s).Fertile lherzolites display non-systematic variation of Rh concentrations and constant Rh/Ir of 0.34 ± 0.03 (1 s, n = 57), indicating a Rh abundance for the primitive mantle of 1.2 ± 0.2 ng/g. The data also suggest that Rh behaves as a compatible element during low to moderate degrees of partial melting in the mantle or melt–mantle interaction, but may be depleted at higher degrees of melting. In contrast, Au concentrations and Au/Ir correlate with peridotite fertility, indicating incompatible behaviour of Au during magmatic processes in the mantle. Fertile lherzolites display Au/Ir ranging from 0.20 to 0.65, whereas residual harzburgites have Au/Ir < 0.20. Concentrations of Au and Re are correlated with each other and suggest similar compatibility of both elements. The primitive mantle abundance of Au calculated from correlations displayed by Au/Ir with Al2O3 and Au with Re is 1.7 ± 0.5 ng/g (1 s).The depletion of Pt, Pd, Re and Au relative to Os, Ir, Ru and Rh displayed by residual harzburgites, suggests HSE fractionation during partial melting. However, the HSE abundance variations of fertile and depleted peridotites cannot be explained by a simple fractionation process. Correlations displayed by Pd/Ir, Re/Ir and Au/Ir with Al2O3 may reflect refertilization of previously melt depleted mantle rocks due to reactive infiltration of silicate melts.Relative concentrations of Rh and Au inferred for the primitive mantle model composition are similar to values of ordinary and enstatite chondrites, but distinct from carbonaceous chondrites. The HSE pattern of the primitive mantle is inconsistent with compositions of known chondrite groups. The primitive mantle composition may be explained by late accretion of a mixture of chondritic with slightly suprachondritic materials, or alternatively, by meteoritic materials mixed into mantle with a HSE signature inherited from core formation.  相似文献   

15.
赵宏樵  赵建如 《现代地质》2007,21(4):654-658
对太平洋CL、CM海山调查时获取9个富钴结壳样品,采用化学处理及ICP-MS法进行分析。对贵金属元素含量分布特征、富集因子、标准化模式以及来源进行探讨和研究。结果表明：海山结壳中贵金属元素Ag、Au、Ru、Rh、Pd、Pt等的平均含量分别为： 1.05×10-6、2.3×10-6、15.6×10-9、22.3×10-9、2.39×10-9和432×10-9。与结核、洋壳及陆地矿石的Pd/（Pt+Pd）、Pt/（Pt+Pd）和Pd/Pt等贵金属元素的比值相比,大洋富钴结壳的 Pd/（Pt+Pd） 比值最低,为0.006;其次是结核,为0.06;洋壳为0.08;陆地矿石的Pd/（Pt+Pd）比值较大,为0.35～0.65。结壳的Pt/（Pt+Pd）比值最高,为0.99;其次是结核,为0.95;洋壳为0.93;陆地矿石的Pt/（Pt+Pd）比值相对较低,为0.33～0.65。统计分析显示了不同区域、不同环境中贵金属元素的特征参数变化,并且说明富钴结壳中富铂、金、钌、铑,而贫钯。贵金属元素标准化显示,海山富钴结壳均存在着Pt、Au正异常和Pd的负异常,其中Au异常幅度与结核的Au异常一致。  相似文献   

16.
The present study describes a method for the extraction of Pt, Pd, Rh, Ru, Ir and Au from various geological materials after fusion with sodium peroxide in zirconium crucibles involving samples that vary in mass from 1 g to more than 20 g. Precipitation is brought about by reduction of the platinum-group elements (PGEs) with Sn2+, using selenium and tellurium as carriers in the presence of a catalyst (KI). The extraction yields obtained by this method are between 95 and 100% for PGEs. Gold is less well extracted (around 80%). Detection of the noble metals in the extraction residues is carried out by using ICP-MS. The results obtained by this technique are reported for five CCRMP certified reference materials and are close to their certified values. The elements were also determined in a natural glass sample melted during a meteoritic impact and contaminated by PGEs at ultra-trace concentrations.  相似文献   

17.
To study the behavior of macrocomponents and admixtures during the fractional crystallization of sulfide melts and the influence of As on noble metals in this process, we performed a quasi-equilibrium directional crystallization of melt of composition (at.%): Fe—35.5, Ni—4.9, Cu—10.4, and S—48.3, with admixtures of Pt, Pd, Rh, Ru, Ir, Au, Ag, As, and Co (each 0.1 at.%), which imitates the average (by Cu contents) compositions of massive ores at the Noril'sk Cu-Ni deposits. The following sequence of phase formation from melt has been established: mss (zone I) / mss + iss (zone II) / iss (zone III) (mss is (FezNi1–z)S1+δ, iss is (FexCuyNi1–x–y)zS1–z); it corresponds to the distribution of main elements along the sample (primary zoning). Distribution curves for macrocomponents in zones I and II of the sample were constructed, as well as the dependencies of their partition coefficients (k) between solid solutions and sulfide melt on the fraction of crystallized melt. The secondary (mineral) zoning resulted from subsolidus phase transformations has been revealed. Five subzones have been recognized: mss + cp (Ia) / mss + cp + pn (Ib) / mss + pc + pn (IIa) / mss + pc + pn + bn (IIb) / pc + bn + pn + unidentified microphases (III). Admixture species in the sample were studied: (1) admixtures dissolved in primary solid solutions and in main minerals resulted from solid-phase transformations and (2) admixtures forming their own mineral phases. The partition coefficients of Co, Rh, and Ru (mss/L), Ru, Ir, and Rh (mss/cp), and Co, Rh, and Pd (mss/pn) were determined. Minerals of noble metals have been recognized: Pt3Fe, PtFe, Au, (Ag,Pd), (Au,Pt), Ag, Ag3Cu, Au3(Cu,Ag,Pd,Pt), etc., and the regularities of their distribution in the sample have been established. It is shown that some noble-metal admixtures are prone to interact with As. Mineral arsenides and sulfoarsenides of noble metals produced during fractional crystallization have been recognized: PtAs2, Pd3As, (RhAsS), (IrAsS), and (Ir,Rh)AsS. The discovered drop-like inclusions of noble-metal arsenides suggest the separation of the initial sulfide-arsenide melt into two immiscible liquids. By indirect features, the micromineral inclusions are divided into primary, crystallized from melt, and secondary, produced in solid-phase reactions. The results of study are compared with literature experimental data obtained by the isothermal-annealing method and with the behavior of noble metals and As during the formation of zonal massive orebodies at the Noril'sk- and Sudbury-type deposits.  相似文献   

18.
Noble Metal Enrichment Processes in the Merensky Reef, Bushveld Complex   总被引：21，自引：7，他引：14  
We have analysed sulphides, silicates, and chromites of theMerensky Reef for platinum-group elements (PGEs), Re and Auusing laser ablation-inductively coupled plasma mass spectrometryand synthetic pyrrhotite standards annealed with known quantitiesof noble metals. Os, Ir and Ru reside in solid solution in pyrrhotiteand pentlandite, Rh and part of the Reef’s Pd in pentlandite,whereas Pt, Au, Re and some Pd form discrete phases. Olivineand chromite, often suspected to carry Os, Ir and Ru, are PGEfree. All phases analysed contain noble metals as discrete micro-inclusionswith diameters typically <100 nm. Inclusions in sulphidescommonly have the element combinations Os–Ir–Ptand Pt–Pd–Au. Inclusions in olivine and chromiteare dominated by Pt ± Au–Pd. Few inclusion spectracan be related to discrete noble metal phases, and few inclusionshave formed by sub-solidus exsolution. Rather, some PGE inclusions,notably those in olivine and chromite, are early-magmatic nuggetstrapped when their host phases crystallized. We suggest thatthe silicate melt layer that preceded the Merensky Reef wasPGE oversaturated at early cumulus times. Experiments combinedwith available sulphide–silicate partition coefficientssuggest that a silicate melt in equilibrium with a sulphidemelt containing the PGE spectrum of the Merensky ore would indeedbe oversaturated with respect to the least soluble noble metals.Sulphide melt apparently played little role in enriching thenoble metals in the Merensky Reef; rather, its role was to immobilizea pre-existing in situ stratiform PGE anomaly in the liquid-stratifiedmagma chamber. KEY WORDS: Bushveld Complex; Merensky Reef; laser-ablation ICP-MS; platinum-group mineralization  相似文献   

19.
淮南煤田深部A组煤中有害微量元素地球化学特征   总被引：1，自引：0，他引：1       下载免费PDF全文
以淮南煤田深部A 组煤为研究对象,全层刻槽采集了煤、夹矸和顶底板岩石样品,采用电感耦合等离子质谱仪 （ICP-MS） 测试分析了样品中13 种有害微量元素的含量,对比研究了其分布特征,结合Tessier 五步形态提取法和相关性分 析探讨了煤中有害微量元素的赋存形态。结果表明：（1） 与中国上陆壳中各种微量元素含量均值相比,淮南深部A 组煤中 B,As,Se,Mo,Cd,Pb,Hg 的富集系数均大于1,在A 组煤中表现为富集;A 组煤中B,As,Se,Cd 的含量均高于淮南煤 田上部B 组煤、华北煤以及中国煤中的含量均值;（2） 相关性分析和逐级提取实验结果表明,A 组煤中微量元素主要以残 渣态和铁锰氧化物结合态存在,两者质量分数之和达到55%~98%,其中Ni,Mo,Cd,Hg,Cu,Pb 和Zn 主要赋存于硫化物 矿物中,Mn 主要赋存于碳酸盐矿物中,V,Cr,Se,B 和As 主要赋存于硅铝酸盐等黏土矿物中。（3） B 元素示踪物源及沉 积环境结果显示,淮南煤田深部A 组煤成煤环境为海相咸水沉积环境,稳定的咸水沉积环境以及受海水影响等因素导致A 组煤中微量元素出现不同程度的富集。  相似文献   

20.
This paper describes the influence of siliceous and iron-rich calcic low-temperature hydrothermal fluids (LTHF) on the mineralogy and geochemistry of the Late Permian No. 11 Coal (anthracitic, Rr=2.85%) in the Dafang Coalfield in northwestern Guizhou Province, China. The No. 11 Coal has high contents of vein ankerite (10.2 vol.%) and vein quartz (11.4 vol.%), with formation temperatures of 85 and 180 °C, respectively, indicating that vein ankerite and vein quartz were derived from low-temperature calcic and siliceous hydrothermal fluids in two epigenetic episodes. The vein quartz appears to have formed earlier than vein ankerite did, and at least three distinct stages of ankerite formation with different Ca/Sr and Fe/Mn ratios were observed.The two types of mineral veins are sources of different suites of major and trace metals. Scanning electron microscope and sequential extraction studies show that, in addition to Fe, Mg, and Ca, vein ankerite is the dominant source of Mn, Cu, Ni, Pb, and Zn in the coal, and the contents of these five elements are as high as 0.09% and 74.0, 33.6, 185, and 289 μg/g, respectively. In contrast, vein quartz is the main carrier mineral for platinum-group elements (PGEs) Pd, Pt, and Ir in the coal, and the contents of Pd, Pt, and Ir are 1.57, 0.15, and 0.007 μg/g, respectively. Sequential extraction showed a high PGE content in the silicate fraction, up to 10.4 μg/g Pd, 1.23 μg/g Pt, and 0.05 μg/g Ir, respectively. It is concluded that the formation of ankerite and quartz and the anomalous enrichment of trace elements in the No. 11 Coal in the Dafang Coalfield, Guizhou, result from the influx of calcic and siliceous low-temperature hydrothermal fluids.  相似文献   

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