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1.
I. Tonguç Uysal Massimo Gasparon Robert Bolhar Jian-xin Zhao Yue-xing Feng Greg Jones 《Chemical Geology》2011,280(1-2):154-169
Extensive Paleozoic sinter deposits occur at the surface associated with sub-surface quartz veining and epithermal Au mineralisation in the Drummond Basin, Australia. We investigated the trace element composition of the sinter deposits and quartz veins in an attempt to develop a new geochemical exploration guide for geological resources. The Drummond Basin hydrothermal silica deposits are unique in having anomalously enriched incompatible element (Cs, Li, Be, U, Th and REE) concentrations in comparison to hydrothermal quartz veins from various granitic-pegmatitic systems elsewhere. The development of relative Ce deficiencies (Ce/Ce*norm < 1) in silica deposits indicate preferential mobilisation of REE over Ce from source rocks by oxidised hydrothermal fluids, leading to relative Ce enrichment in the source material (e.g., rhyolite intrusions). Sinters and quartz veins and some volcanic source rocks show a conspicuous positive Y anomaly relative to REE. This is interpreted in terms of Y fractionation due to fluorine complexation with REE during hydrothermal activity. The majority of sinter and quartz samples within or near the Au mineralisation zone are more enriched in mobile elements (Cs, Li, Rb and Be) than the silica deposits from areas distal to the mineralised area. Normalised Y–REE patterns of the sinter deposits, quartz veins, and wall rocks provide important information on the physico-chemical environment of epithermal mineral deposition in geothermal systems. Trace element systematics as revealed in the current study, particularly in relation to the alkali element mobility, have significant implications for finding new prospect areas and evaluating the potential of existing prospect areas for epithermal metal deposits and active geothermal fields. 相似文献
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In this research, a float-sink test was applied to a Late Permian high-sulfur coal collected from Pu’an coalfield, Southwest in Guizhou, China. To investigate the occurrence modes and the mobility of various trace elements, as well as the cleaning potential of some harmful elements in density separation, coal quality parameters and concentrations of 46 elements of 7 density fractionated samples were determined and statistically analyzed. Results show that larger size and higher density fractions have higher total sulfur content and ash yield than the smaller and lower ones. In fact, most (74.39 %) of the total sulfur occurs in the inorganic matter. Affinity and correlation analysis show that Mo and Ni have apparently strong organic affinity, whereas Rh, Cs, Sr, Co, Nb, Zr, V, Ga, Sc, Be, Ge, Hf, Th, U, Ag, As, In, Cu, Cd, Ta, Li, TI, and Ba are mostly in the heavy fractions. Rare earth element (REE) patterns for the seven density fractions present good uniformity and show that they are of right-inclined pattern type characterized by Light REE (LREE, La ~ Eu) enrichment relative to Heavy REE (HREE, Gd ~ Lu) and pronounced negative δ Eu anomalies. This suggests that REE was mainly derived from basalt-weathered materials. LRREE/HREE ratio variations reveal that LREE has stronger affinity with the organic matter relative to the HREE, while high LRREE/HREE in heavy fractions may be related to pyrite. Supposing the maximum sulfur content of the cleaned coal is 1.00 %, the theoretical removal ratios of Co, TI, and Ba are as high as 90.94, 93.73, and 92.29 %, respectively, while those of As, Ni and Mo are only 56.33, 48.85, and 45.05 %, respectively. As these figures change with different maximum sulfur contents required for the cleaned coal, not only the decrease of sulfur and ash in coal washing, but also the mobility of some harmful trace elements should be taken into consideration. 相似文献
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为探讨滇西户撒盆地新近系褐煤的微量元素地球化学特征及指示意义,采集了5口验证钻孔内15层褐煤的新鲜样品,利用ICP-MS对微量元素含量进行测试。结果表明,与中国煤微量元素背景值进行比较,户撒盆地褐煤Rb、Cs、Th富集,Be、Sc、Cr、Cu、Ga、In、W、Pb、U稍富集。户撒褐煤富集的潜在有害微量元素有Be(5.32mg/kg)、Cr(39.8mg/kg)、Cu(39.7 mg/kg)、Pb(32.8 mg/kg)、Th(39.3 mg/kg)和U(7.39 mg/kg)。褐煤的REE总量为196.03~550.42 mg/kg,平均为306.71 mg/kg,远高于中国煤的REE总量均值(136 mg/kg),表现出LREE明显富集,HREE相对亏损特征。δCe值负异常与微量元素比值特征均表明户撒泥炭的沉积期主要为酸性还原环境。δE负异常与球粒陨石标准化分配模式表明户撒新近系褐煤稀土元素与盆缘酸性花岗岩的陆源供给有关。 相似文献
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Rare-metals mineralization at Brockman, Western Australia, is the product of early pyroclastic eruption of trachytic magma enriched in volatiles and incompatible elements such as Zr, Hf, Nb, Ta, Be, Y and REE and Ga. The mineralization is fine-grained (<20 m) and is the result of alteration and re-mobilization of comparatively simple magmatic precursor minerals such as columbite and zircon by F-rich deuteric solutions that were retained in an ash-flow tuff (the Niobium Tuff) following eruption. Chondrite normalized REE distributions show strong enrichment in HREE. Gel-zircon is the principal residence of the HREE, disseminated bastnaesite (±parisite and synchisite) carries the LREE and bertrandite, in late-stage calcite veins, is the host for Be. Ga occurs in K-mica in the groundmass. Trachytic flows overlying the Niobium Tuff contain many of the same ore minerals, but in trace amounts. 相似文献
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为研究准格尔串草圪旦5号煤微量元素地球化学特征,采用光学显微镜、扫面电子显微镜和X射线衍射（XRD）方法观测煤中矿物组成及形态特征,应用电感耦合等离子质谱（ICP MS）方法测定煤中多种微量元素含量,运用数理统计方法研究微量元素在煤中的赋存特征。结果表明：5号煤中Li、Be、F、U、Hg 5种元素相对富集,含量高于研究区6号煤及中国煤中含量水平。5号煤中Li、F、Ga、Se无机亲和性强,Be、As、U为亲有机元素;Hg与硫含量显著正相关。各元素在煤中主要以有机结合态、无机结合态和硫化物结合态赋存。 相似文献
7.
河北兴隆M111稀有金属花岗岩体地球化学和矿化特征研究 总被引：2，自引：0，他引：2
本文研究河北兴隆一个复式小花岗岩体的岩石地球化学和矿化特征.常量氧化物、Rb-Sr同位素、稀土元素和稀有微量元素的地球化学特点综合表明,该岩体是起源较深的花岗岩浆经过较充分地分异演化的晚阶段产物.岩浆成分向着富钠富钠碱元素富挥发分的方向有规律的分异演化导致Nb,Ta,Li,Be,Rb,Cs等稀有元素富集和矿化.最晚形成的空间上位于岩体较高部位的白色似斑状铁锂云母-钠长石花岗岩,是矿化的有利地段,可作为稀有金属矿床找矿的岩石学标志 相似文献
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四川甲基卡新三号(X03) 超大型锂矿脉是近年发现且价值巨大的锂矿化伟晶岩脉,但相对缺少地球化学的研究,利用ICP-MS测试手段对该矿脉ZK1101钻孔中44件样品进行分析测试,发现该矿脉稀土总量很低(∑REE为0.180×10-6~8.613×10-6,平均值为2.543×10-6),配分曲线呈右倾斜型,相对富集轻稀土,总体表现铕负异常.围岩的稀土含量与一般片岩相近(∑REE为160.134×10-6~265.881×10-6,平均值为230.718×10-6),稀土配分曲线总体呈右倾平滑趋势,富集轻稀土,铕为负异常.铕的分布具有特殊性,表现为铕在伟晶岩脉的边部具有显著的正异常.∑REE与Li呈负相关性,δCe与Li则表现为弱正相关性.这一首次发现的低稀土总量和矿脉边部Eu显著正异常的特殊性,对于甲基卡伟晶岩的含矿性评价可能具有重要意义. 相似文献
10.
Inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectroscopy, hydride generation-atomic fluorescence spectrometry, emission spectrometry, X fluorescence spectrometry, and X-ray diffraction were employed to study the geochemistry and mineralogy of coal gangues from Nos. 2, 3, and 8 coal seams of the Du’erping coal mine, Xishan coalfield, Taiyuan, Shanxi Province. The study revealed that compared with the sedimentary cover, upper continent crust, Carboniferous-Permian coal from North China, as well as most coal in China, coal gangues from Nos. 2 and 3 coal seams are rich in Li, Be, Sc, Cr, Cu, Ga, Ba, Th, Nb, Cd, Pb, Ta and rare-earth elements, and coal gangues from No. 8 coal seam are rich in Li, Sc, V, Cr, Ga, U, and rare-earth elements. Compared with the Carboniferous-Permian coal from North China and most coal in China, coal gangues from Nos. 2, 3 and 8 seams are rich in Rb, V, Cs and Sr. Therefore, The Du’erping coal gangues in the Xishan coalfield are rich in most hazardous trace elements and rare-earth elements, wherein the contents of Ga and Li reach the industrial grade and have significance for industrial utilization. On the whole, coal gangues of the Shanxi Formation from the Permian are rich in more trace elements than those of the Carboniferous Taiyuan Formation. The distributions of REE show obviously dipping rightwards with negative Eu anomalies. The contents of rare-earth elements in the three seams are quite different. All of the above indicate that the source of the rare-earth elements is terrigenous debris. Minerals in No. 2 seam identified by X-ray diffraction mainly include quartz, kaolinite, in addition to calcite, pyrite, apatite, epidote, and epsomite. No. 3 seam mainly contains quartz, kaolinite, in addition to a small amount of sodium feldspar, calcium nitrate, iron ore, gypsum, and vivianite. No. 8 seam mainly contains kaolinite, dickite, quartz, illite, and a small amount of hematite and U. The correlations between major elements and trace elements in coal gangues of the Du’erping coal mine analyzed by using SPSS (Statistical Product and Service Solutions) indicate that the trace alkali elements and rare-earth elements occur mainly in such clay minerals as kaolinite. 相似文献
11.
Dr. H. Khalili 《Mineralogy and Petrology》1972,18(2):79-104
Zusammenfassung 139 Proben von Gesteinen und Mineralen des Villacher Granites und von Pegmatitvorkommen im Kärntner Altkristallin (Kärnten/Österreich) sowie vergleichsweise 13 Proben von anderen Pegmatiten der Ostalpen und solchen der Böhmischen Masse wurden mit Hilfe flammenphotometrischer, emissionsspektrographischer, röntgenfluoreszenzspektrometrischer und teilweise auch gammaspektrometrischer Methoden auf die Elemente Li, Na, K, Rb, Be, Ca, Sr, Ba, B, Sc, Y, Yb, (Th, U), Ti, Zr, Ni und Ga analysiert.Es konnte gezeigt werden, daß zwischen dem voralpidischen Villacher Granit und dem pegmatitischen und aplitischen Ganggefolge im Kärntner Altkristallin zwischen Ossiacher See und Drautal Blutsverwandtschaft bestehen sollte.Mit zunehmender Größe des Pegmatitvorkommens und offenbar auch mit Annäherung an den Granit nimmt der Gehalt an Li, Rb, Be, B, Ga und Pb zu, der Gehalt an Ca, Sr, Ba, Ti, Sc u. a. hingegen ab. Das K/Rb-Verhältnis ist ebenso ein verläßlicher Indikator. In kleineren Pegmatitkörpern nähert sich der Gehalt der pegmatophilen Spurenelemente dem des Nebengesteins.Es werden Abhängigkeiten zwischen Mindestkonzentrationen und Mineralisationen gefunden: Granite der Ostalpen mit Berylliumgehalten über 5 ppm Be lassen Beryllmineralisationen in ihren Pegmatiten erwarten. In Pegmatit-Proben mit über 50 ppm Be sind unter dem Mikroskop Beryllnädelchen nachweisbar.Zinnstein tritt auf, wenn das Pegmatitgestein mehr als 20 ppm Sn enthält, Spodumen bei>0,1% Li und Xenotim bei>20 ppm Y.
Mit 7 Abbildungen 相似文献
Contribution to the geochemistry of some pegmatites in the Eastern Alps
Summary 139 samples of rocks and minerals from the granite of Villach and from pegmatites of the Carinthian Old Cristalline Complex (Austria) and additional 13 samples for comparison purposes from other pegmatites in the Eastern Alps and the Bohemian Mass were analyzed for the elements Li, Na, K, Rb, Be, Ca, Sr, Ba, B, Sc, Y, Yb, (Th, U), Ti, Zr, Mn, Co, Ni, and Ga using flamephotometric, emission-spectrographic, x-ray-fluorescence spectrometric and partially gamma-spectrometric methods.It could be shown that the prealpidic granite of Villach and the pegmatites of the Carinthian Old Cristalline Complex lying between the Lake of Ossiach and the Drau Valley are probably consanquineous. The contents of Li, Rb, Be, B, Ga, and Pb increase with the size of the pegmatite and with increasing proximity to the granite. Other elements, like Ca, Sr, Ba, Ti, Sc, show the reverse relation.Also the K/Rb-ratio is a good indicator. The trace-element content of small pegmatite bodies approaches that of the wall rocks.Relationships between the concentration of some elements and the mineralization have been found: One may expect beryllium minerals in pegmatites of granites of the Eastern Alps if the granite contains more than 5 ppm Be. Pegmatites samples containing more than 50 ppm Be show needles of beryll under the microscope. Cassiterite appeares, if the content of the pegmatitic rock reaches 20 ppm Sn, spodumen, if it exceeds 0,1% Li, and Xenotim, if it exceeds 20 ppm Y.
Mit 7 Abbildungen 相似文献
12.
五台地区高凡群对于华北克拉通早前寒武纪变质地层层序建立具有重要意义。本文对高凡群磨河组开展了地球化学和锆石年代学研究。变质沉积岩稀土总量为(132.78~231.84)×10-6(样品W1927的稀土总量为1016.55×10-6),轻重稀土分离弱((La/Yb)N=4.5~12.5),具明显负铕异常(δEu=0.37~0.62),稀土模式与太古宙后泥砂质碎屑沉积岩十分类似。一个白云石英片岩样品(D004)的变质原岩中存在大量2.7 Ga、2.54~2.5 Ga、2.3 Ga和2.18 Ga碎屑锆石,最年轻锆石可能来自同时代火山岩。一个含黄铁矿白云片岩样品(W1927)的最年轻锆石年龄为2194 Ma,被认为代表了岩石形成时代。结合前人研究,可把高凡群形成时代限定在<2176 Ma和2350 Ma之间,碎屑物质主要来自恒山、五台、阜平、云中山、吕梁地区新太古代—古元古代变质基底或更远的地区。 相似文献
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Trace Elements and Rare Earth Elements of Sulfide Minerals in the Tianqiao Pb-Zn Ore Deposit, Guizhou Province, China 总被引：2，自引：0，他引：2
ZHOU Jiaxi HUANG Zhilong ZHOU Guofu LI Xiaobiao DING Wei BAO Guangping 《《地质学报》英文版》2011,85(1):189-199
Trace elements and rare earth elements (REE) of the sulfide minerals were determined by inductively-coupled plasma mass spectrometry. The results indicate that V, Cu, Sn, Ga, Cd, In, and Se are concentrated in sphalerite, Sb, As, Ge, and Tl are concentrated in galena, and almost all trace elements in pyrite are low. The Ga and Cd contents in the light-yellow sphalerites are higher than that in the brown and the black sphalerites. The contents of Ge, Tl, In, and Se in brown sphalerites are higher than that in light-yellow sphalerites and black sphalerites. It shows that REE concentrations are higher in pyrite than in sphalerite, and galena. In sphalerites, the REE concentration decreases from light-yellow sphalerites, brown sphalerites, to black sphalerites. The ratios of Ga/In are more than 10, and Co/Ni are less than 1 in the studied sphalerites and pyrites, respectively, indicating that the genesis of the Tianqiao Pb–Zn ore deposit might belong to sedimentary-reformed genesis associated with hydrothermal genesis. The relationship between LnGa and LnIn in sphalerite, and between LnBi and LnSb in galena, indicates that the Tianqiao Pb–Zn ore deposit might belong to sedimentary-reformed genesis. Based on the chondrite-normalized REE patterns, δEu is a negative anomaly (0.13–0.88), and δCe does not show obvious anomaly (0.88–1.31); all the samples have low total REE concentrations (<3 ppm) and a wide range of light rare earth element/high rare earth element ratios (1.12–12.35). These results indicate that the ore-forming fluids occur under a reducing environment. Comparison REE compositions and parameters of sphalerites, galenas, pyrites, ores, altered dolostone rocks, strata carbonates, and the pyrite from Lower Carboniferous Datang Formation showed that the ore-forming fluids might come from polycomponent systems, that is, different chronostratigraphic units could make an important contribution to the ore-forming fluids. Combined with the tectonic setting and previous isotopic geochemistry evidence, we conclude that the ore-deposit genesis is hydrothermal, sedimentary reformed, with multisources characteristics of ore-forming fluids. 相似文献
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Cigdem Saydam Eker Ferkan Sipahi Abdullah Kaygusuz 《Chemie der Erde / Geochemistry》2012,72(2):167-177
Trace elements and rare earth elements (REEs) of Lias-aged cherts in the Gumushane area were studied in order to understand their origin and depositional environment. Twenty three chert samples from five stratigraphic sections were analysed by inductively coupled plasma-mass spectrometry, X-ray diffraction, and mineralogical investigation. Lias cherts in the study area are microcrystalline, cryptocrystalline quartz, and megaquartz depending on mineralogical content. Trace elements of the cherts were compared with PAAS, Co, Y, and Th had stronger depletions in the five sections, whereas V, Ni, Zr, Nb, and Hf had smaller depletions. The distribution of Zr, Hf, and Ta yields Zr/Hf, Zr/Ta and Hf/Ta ratios (25/645, 37/665, and 0.18/3, respectively) that differ from those of chondrites and average upper continental crust, suggesting that these elements are likely non-detrital but are sourced from seawater. Th/U ratios range from 0.04 to 0.45 and are lower than those of the upper continental crust (average: 3.9). Lias-aged cherts have low total REE abundances and stronger depletions in five sections of the PAAS and chondrite-normalised plots. The cherts are characterised by a positive Eu anomaly (average: 4.9) and LREE-enrichment (LaN/YbN = average: 3.5). In addition, about one-half of the cherts exhibit positive Ce anomaly (range: 0.25–2.58), chondritic Y/Ho values (range: 3.3–60), and low (La/Ce)N values (average: 1.8). REE and trace element abundance in Lias cherts indicate that these elements were likely derived from hydrothermal solutions, terrigenous sources, and seawater. The REE patterns of the cherts show that they were probably deposited close to a continental margin. 相似文献
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A. V. Maslov A. D. Nozhkin V. N. Podkovyrov E. F. Letnikova N. V. Dmitrieva Yu. L. Ronkin 《Russian Journal of Pacific Geology》2010,4(5):379-397
The clarkes of concentrations (Kc) of a wide range of trace elements (Li, Be, B, Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In,
Sb, Cs, Ba, REE, Hf, Ta, Hg, Tl, Pb, Bi, Th, and U) were analyzed for fine-gained terrigenous rocks (mudstones, metapelites)
from the reference Riphean sections of the Uchur-Maya region and the Yenisei Range. It was established that the shales and
mudstones of the Uchur and Aimchan groups in the Riphean hypostratotype section are characterized by moderate (2.5 < Kc < 5) and intense (Kc > 5) geochemical specialization for Li, B, and Zn. At the same time, the similar rocks of the Lakhanda and Ui groups do not
exhibit any distinct geochemical specialization, although they are notably enriched in HREE. The metapelites from the basal
formations of the Riphean sedimentary successions in the Yenisei Range are distinctly specialized for B and slightly for Li,
Rb, Be, Nb, Ta, Th, Ge, and Cd. In addition, moderate specialization for Cu is characteristic of the metapelites from the
Korda and Lopatino formations; for Bi, Sb, Hg, and V, for their analogs from the Potoskui Formation; and, for Hg and Cs, for
the similar rocks from the Lopatino Formation. The metapelites of the Lower Riphean Korda Formation from the central zone
of the Yenisei Range have elevated contents of significantly more elements (Li, Be, Sc, V, Cr, Co, Ni, Zn, As, Rb, Y, Zr,
Nb, Sb, Ag, In, Hf, Hg, and others) than their counterparts from its eastern near-platform part. The mudstones of the ore-bearing
(Pb, Zn) Gorevo Formation are characterized by elevated concentrations of several ore elements such as Pb, Cd, As, Sb, and
Bi. The elevated Kc values of the rare lithophile and of several ore elements in the metapelites of the Yenisei Range are determined by the high
geochemical differentiation of the Early Precambrian blocks constituting the western margin of the Siberian Craton, which
were eroded in the Riphean, and the syn-sedimentary riftogenic and intraplate magmatism. On the contrary, the fine-grained
and terrigenous rocks from the basal part of the Riphean section in the Uchur-Maya region are compositionally closer to the
immature Late Archean substrates or their Early Proterozoic analogs. 相似文献
17.
Riad A. Higazy 《Geochimica et cosmochimica acta》1952,2(3):170-184
The epidioritc and quartzite of the Malin Head district, (Ireland) are considered by Holmes and Reynolds [7] to be metasomatically transformed into skarn-rocks and mica-schist respectively. The trace element contents of these rocks were investigated using semi-quantitative methods in order to study the behaviour of the different trace elements during the metasomatic changes which have taken place. The elements which have been determined are Rb, Ba, Ag and Pb; Sr, Y and La; Li, Cr, Ni, Co, V, Cu, Sc, Sn and Mo; Ga; Zr, Be, Tl, Ge and In. The trace elements follow the major elements for which they can substitute in favourable crystal lattices, the substitution being in accord with Goldschmidts rules. Rb, Ba and probably Pb and Ag follow and substitute for K; Sr and Y for Ca and probably K; Li, Cr, Ni, Co, V, Cu, Sc, Sn and Mo for Mg, Fe2 and Fe3; and Ga for Al. 相似文献
18.
Concentration and distribution of elements in Late Permian coals from western Guizhou Province,China
《International Journal of Coal Geology》2005,61(1-2):119-137
With the aim of better understanding geochemistry of coal, 71 Late Permian whole-seam coal channel samples from western Guizhou Province, Southwest China were studied and 57 elements in them were determined. The contents of Al, Ca, Co, Cr, Cu, Fe, Ga, Hf, K, Li, Mn, Mo, Nb, Ni, Sn, Ta, Ti, Th, U, V, Zr, and REEs in the Late Permian coals from western Guizhou Province are higher than the arithmetic means for the corresponding elements in the US coals, whereas As, Ba, Br, F, Hg, P, Se, and Tl are lower. Compared to common Chinese coals, the contents of Co, Cr, Cu, Ga, Hf, Li, Mn, Mo, Ni, Sc, Sn, Ti, U, V, Zn, and Zr in western Guizhou coals are higher, and As, F, Hg, Rb, Sb, Tl, and W are lower. Five groups of elements may be classified according to their mode of occurrence in coal: The first two, Group A, Tm–Yb–Lu–Y–Er–Ho–Dy–Tb–Ce–La–Nd–Pr–Gd–Sm, and Group B, As–Sr–K–Rb–Ba–F–Ash–Si–Sn–Ga–Hf–Al–Ta–Zr–Be–Th–Na, have high positive correlation coefficients with ash yield and they show mainly inorganic affinity. Some elements from Group B, such as Ba, Be, Ga, Hf, and Th, are also characterized by significant aluminosilicate affinity. In addition, arsenic also exhibits high sulfide affinity (rS–Fe>0.5). The elements, which have negative or lower positive correlation coefficients with ash yield (with exceptions of Bi, Cs, Nb, Mn, Se, and Ti), are grouped in other four associations: Group C, Cr–V–Mo–U–Cd–Tl; Group D, Hg–Li–Sc–Ti–Eu–Nb–Cs–W; Group E, Bi–Sb; and Group F, Co–Ni–Cu–Pb–Zn–Mg–Se–Ca–Mn–S–Fe. The correlation coefficients of some elements, including Co, Cr, Cu, Fe, Hg, Li, Mo, Ni, P, S, Sc, U, V, and Zn, with ash yield are below the statistically significant value. Only Cr and Cu are negatively correlated to ash yield (−0.07 and −0.01, respectively), showing intermediate (organic and inorganic) affinity. Manganese and Fe are characterized by carbonate affinity probably due to high content of epigenetic veined ankerite in some coals. Phosphorus has low correlation coefficients with any other elements and is not included in these six associations. There are five possible genetic types of enrichment of elements in coal from western Guizhou Province: source rock, volcanic ash, low-temperature hydrothermal fluid, groundwater, and magmatic hydrothermal inputs. 相似文献
19.
新疆阿尔泰南缘克因布拉克铜锌矿区黑云母二长花岗岩地球化学特征及意义 总被引：1，自引：0，他引：1
新疆阿尔泰南缘克因布拉克铜锌矿区出露大面积花岗岩,岩性主要为二长花岗岩、钾长花岗岩、黑云母花岗岩和英云闪长岩,矿体赋存于二长花岗岩与上志留统-下泥盆统康布铁堡组外接触带中。室内显微镜下鉴定二长花岗岩发育二云母二长花岗岩和黑云母二长花岗岩2种岩相。黑云母二长花岗岩具有高硅、高碱、贫钠富钾、准铝质-过铝质的特点;微量元素特征表现为Rb、Th、K、Ce、Nd、Tb富集,Ba、Nb、Sr、Ti强烈亏损;稀土元素配分模式为轻稀土相对富集的右倾型,具有稀土总量中等及中等负铕异常的特点。这些特征表明该花岗岩属于高钾钙碱性准铝质-过铝质S型。岩石的ISr(t)值为0.703 039~0.705 729,εNd(t)值相对较低,多数为近于0的负值,T2DM两阶段模式年龄集中在1.145~1.194 Ga。岩石可能由中元古界富含黑云母的变质砂岩或正变质岩和少量幔源物质在较低压力条件下熔融形成,源区有斜长石的残留。地球化学特征表明该区花岗岩具有良好的含矿性,其矿床形成于后碰撞的伸展环境,成矿作用与二长花岗岩的岩浆期后热液有关。 相似文献
20.
Accumulation and sources of heavy metals in urban topsoils: a case study from the city of Xuzhou, China 总被引：8，自引：0，他引：8
The knowledge of the variability, the anthropogenic versus natural origin and corresponding environmental risk for potentially harmful elements in urban topsoils is of importance to assess human impact. The aims of the present study were: (1) to assess the distribution of heavy metals (Sn, Li, Ga, Ba, Fe, Mn, Co, Be, Ti, Al, Hg, Cr, Sb, As, Bi, Pd, Pt, Au, Ni, Cd, Zn, Cu, Pb, Se, Mo, Sc and Ag) in urban environment; (2) to discriminate natural and anthropogenic contributions; and (3) to identify possible sources of pollution. Multivariate statistic approaches (principal component analysis and cluster analysis) were adopted for data treatment, allowing the identification of three main factors controlling the heavy metal variability in Xuzhou urban topsoils. Results demonstrate that Hg, Cr, Sb, As, Bi, Pd, Pt, Au, Ni, Cd, Br, Zn, Cu, S, Pb, Se, Mo, Sc and Ag could be inferred to be tracers of anthropogenic pollution, whereas Al, Ti, Ga, Li, V, Co, Pt, Mn and Be were interpreted to be mainly inherited from parent materials. Iron, Ba, Sn, Pd and Br were interpreted to be affected by mixed sources. 相似文献