黔中—渝南铝土矿含矿岩系微量元素区域分布特征及物质来源探讨          下载免费PDF全文

刘平  韩忠华  廖友常  聂坤 《贵州地质》2020,37(1):1-13

黔中—渝南成矿带石炭纪铝土矿含矿岩系,分别形成于修文、息烽—遵义和黔北—渝南三个沉积区,大多数铝土矿属产于碳酸盐岩侵蚀面上的、少数为产于泥页岩侵蚀面上的硬水铝石沉积型铝土矿床。修文沉积区铝土矿中Zr、RE2O3含量最多,息烽—遵义沉积区铝土矿中Ga含量最多,黔北—渝南沉积区Li含量最多,各有特色。修文沉积区铝土矿含矿岩系的母岩,是其下伏寒武系碳酸盐岩与下奥陶统页岩、灰岩、白云岩;息烽—遵义沉积区含矿岩系的母岩为下伏下奥陶统页岩、灰岩及白云岩;黔北—渝南沉积区含矿岩系的母岩,是下伏下志留统泥、页岩和上石炭统石灰岩。碳酸盐岩中Al2O3与稳定的微量元素含量甚少,要演变成大面积铝土矿,必须要配以足够的含Al2O3和微量元素较多的泥、页岩,才可能满足形成大规模铝土矿的物质需求。  相似文献   

格尔木河水质现状及生态风险评估          下载免费PDF全文

李雷明  武君  徐娟  温小虎  闵秀云  郭效瑛  柴小丽  李廷伟 《盐湖研究》2019,27(1):89-98

为了解经济迅速发展背景下格尔木河流域水体中痕量元素分布、水环境质量现状和生态风险,对格尔木河9个采样点水样21种痕量元素的分布及相关性进行了分析,以Cu、Zn、Hg、Cd、Cr和Pb为目标重金属,评估了格尔木河水质现状及生态风险。结果表明:重金属Pb浓度在所有水样中均低于检出限,其它痕量元素浓度在0.001(Cd)～6297.013(Sr)μg·L~(-1)范围变化。根据相关性分析,推测格尔木河水体中Li、Sc、Ti、V、Cu、Ge、Rb、Sr、Mo、Cd来源可能相同。采样点水样6种重金属浓度均达到地表水环境质量I类的标准。采用5种方法评价了格尔木河水质现状,研究区水质处于无污染的理想状态。格尔木河重金属引发的潜在生态风险处于低风险水平(生态风险指数变化范围为0.35～0.68)。  相似文献   

滇东南都龙超大型锡锌多金属矿床黄铁矿LA-ICPMS微量元素组成研究     

刘仕玉  刘玉平  叶霖  王大鹏 《岩石学报》2021,37(4):1196-1212

滇东南马关都龙是一个以锡锌为主,共-伴生铟、铜、铅、钨、铁、银等多种元素的锡锌多金属超大型矿床。虽然前人从矿物学、矿床地球化学、年代学等不同角度开展了较多的研究,该矿床锡锌多金属矿化为燕山晚期岩浆热液活动的产物已是不争的事实,但关于该矿床是否存在热水沉积作用及其与锡锌多金属成矿作用的关系依然存在较大争议。本文选取都龙矿区广泛存在的黄铁矿作为主要研究对象,在矿相学基础上利用LA-ICPMS对不同阶段黄铁矿的微量元素组成开展了系统的研究。野外及显微鉴定结果表明,矿区存在四种类型(期次)的黄铁矿,即:鲕状黄铁矿Py1;穿切或交代Py1的细脉状黄铁矿Py2;与闪锌矿等硫化物共生的自形黄铁矿Py3;包裹早期黄铁矿或闪锌矿等硫化物的他形黄铁矿Py4。LA-ICPMS分析结果表明,该矿床黄铁矿中富集多种微量元素,其中Co、Ni、As、Ge等元素以类质同象的形式存在黄铁矿晶格中,而其余元素多以显微矿物包体形式赋存于黄铁矿中。上述四期黄铁矿微量元素组成存在较大差别,Py1相对富集Zn和As,而其余微量元素含量较低,Co与Ni含量较低,Co/Ni比值远低于1.00,其微量元素组成与典型沉积作用形成黄铁矿基本一致; Py2与Py1具有相似的微量元素组成特征,其Co/Ni比值接近Py1变化范围; Py3和Py4除富集Zn、As外,Mn、Co、Ni、Cu、Sb、Pb、Bi元素含量也相对较高,其Co/Ni比值相对较高,多大于1,与典型岩浆热液型黄铁矿微量元素组成相似,而与沉积型黄铁矿差异明显。结合各阶段黄铁矿产出地质特征,对比不同类型黄铁矿微量元素组成,本研究认为:Py1鲕状黄铁矿为热水沉积作用形成; Py2为Py1变质改造形成的细脉状黄铁矿,其微量元素继承了Py1; Py3为岩浆热液活动形成的自形黄铁矿; Py4为岩浆热液活动晚期形成的他形黄铁矿,Ag和Bi组成作为区分不同成因类型黄铁矿的化学指标的潜力。矿区早期沉积作用形成鲕状黄铁矿过程可能为后期成矿作用提供了部分硫源及少量Zn等成矿物质,海西-印支期区域变质改造作用对矿区成矿作用影响不大,而燕山晚期岩浆热液活动才是矿区锡多金属大规模成矿作用的主导因素。  相似文献   

Pyroxenite xenoliths and clinopyroxene megacrysts from the Cenozoic Jbel Saghro Volcanic Field (Anti-Atlas,Morocco): Petrography,mineral chemistry and equilibration conditions     

《Chemie der Erde / Geochemistry》2021,81(1):125694

A suite of mafic pyroxenite xenoliths and clinopyroxene megacrysts was brought to the surface by Cenozoic nephelinites of the Jbel Saghro Volcanic Field (Anti-Atlas, Morocco). The large population of samples was subdivided into five groups: (i) clinopyroxenites sensu stricto; (ii) olivine clinopyroxenites; (iii) mica-bearing clinopyroxenites; (iv) kaersutite-bearing clinopyroxenites; (v) clinopyroxene megacrysts. These xenoliths display a cumulate texture (adcumulate, heteradcumulate with poikilitic clinopyroxene including olivine). The clinopyroxenes have the composition of augite and show an appreciable variation of MgO (7.02–14.80 wt.%), TiO₂ (0.58–5.76 wt.%) and Al₂O₃ (2.81–12.38 wt.%) contents in grains. The clinopyroxenes are characterized by convex upward chondrite-normalized REE patterns, they display very similar trace element compositions with low contents of incompatible elements such as Rb (0−0.9 ppm), Ba (0.1–8.3 ppm), Th (0.1−0.3 ppm), U (0.01−0.04 ppm) and Nb (1.3–3.2 ppm). REE contents of the calculated melts in equilibrium with the clinopyroxene megacrysts and clinopyroxene from pyroxenite xenoliths are similar to those of the nephelinites exposed in Jbel Saghro. Crystallization temperatures of pyroxenite xenoliths and clinopyroxene megacrysts range from 950 °C to 1150 °C. Clinopyroxene barometry yielded pressure of crystallization ranging from 0.4 to 0.8 GPa for pyroxenite xenoliths and 0.3 to 0.7 GPa for clinopyroxene megacrysts. This pressure range is in agreement with pyroxenite xenoliths and clinopyroxene megacrysts being crystallized from their parental melts at the lower and upper crust.  相似文献   

微量元素分析在判别沉积环境中的应用——以柴达木盆地西部锶矿区富锶地层为例          下载免费PDF全文

年秀清  韩凤清  韩继龙  毛庆飞  马喆 《盐湖研究》2019,27(1):66-72

沉积岩中的微量元素对沉积环境水介质的变化较为敏感,是研究沉积物沉积时古气候、古环境的有效手段。选取了对沉积环境介质较为敏感的锶(Sr)、钡(Ba)、铜(Cu)、铀(U)、钒(V)、镍(Ni)、钍(Th)等元素作为判别指标,对柴达木盆地西部上新统油砂山组、狮子沟组和更新统七个泉组三套富锶岩层的古气候和古沉积环境特征进行了研究。结果表明,柴达木盆地西部从油砂山组到七个泉组沉积时总体上为干旱的气候环境;湖盆水体的盐度较高,表现为咸水环境,且从油砂山组到七个泉组随着地层变新,盐度有逐渐增大的趋势;油砂山组、狮子沟组和七个泉组沉积时湖盆水体均表现为中等分层、湖水循环较为顺畅的氧化环境。  相似文献   

Investigation of trace metals distribution in water,sediments and wetland plants of K(i)z(i)l(i)rmak Delta,Turkey     

Mehmet Soner Engin  Ahmet Uyanik  Seydahmet Cay 《国际泥沙研究》2017,32(1)

In this study,accumulation and distribution of Pb,Cu,Zn,Co,Ni,Mn and Fe in water,bottom sediments and four plant species (Myriophyllum verticillatum,Hydrocharis morsus-ranae,Nymphaea alba and Typha latifolia) were investigated in (C)ernek Lake of Kizihrmak Delta.The Kizdirmak Delta is one of the largest natural wetlands of Turkey and it is protected by the Ramsar convention since 1993.Selected physico-chemical parameters such as pH,conductivity and dissolved oxygen and also trace metal concentrations were monitored in water.All the parameters obtained were found higher than that of the national standards for the protected lakes and reserves.The accumulated amounts of various trace metals in bottom sediments and wetland plants were found in the following order of Fe ＞ Mn ＞ Zn ＞ Ni ＞ Co ＞ Cu ＞ Pb and Fe ＞ Mn ＞ Zn ＞ Ni ＞ Co respectively.The historical trace metal intake of Myriophyllum verticillatum,Hydrocharis morsus-ranae,Typha latifolia and Nymphaea alba were obtained higher than that of the toxic metal levels and these plants may be accepted as accumulators for the detected trace metals and also bioindicators in the historically polluted natural areas.  相似文献   

Sorption of Pb,Cu, Cd,and Zn by Municipal Solid Waste Composts: Metal Retention and Desorption Mechanisms     

《洁净——土壤、空气、水》2017,45(1)

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A Multi‐Element Ion‐Pair Extraction for Trace Metals Determination in Environmental Samples     

Şerife Saçmacı  Şenol Kartal 《洁净——土壤、空气、水》2011,39(6):577-583

A multi‐element ion‐pair extraction method was described for the preconcentration of Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Ni(II), Pb(II), and Zn(II) ions in environmental samples prior to their determinations by flame atomic absorption spectrometry (FAAS). As an ion‐pair ligand 2‐(4‐methoxybenzoyl)‐N′‐benzylidene‐3‐(4‐methoxyphenyl)‐3‐oxo‐N‐phenyl‐propono hydrazide (MBMP) was used. Some analytical parameters such as pH of sample solution, amount of MBMP, shaking time, sample volume, and type of counter ion were investigated to establish optimum experimental conditions. No interferences due to major components and some metal ions of the samples were observed. The detection limits of the proposed method were found in the range of 0.33–0.9 µg L^?1 for the analyte ions. Recoveries were found to be higher than 95% and the relative standard deviation (RSD) was less than 4%. The accuracy of the procedure was estimated by analyzing the two certified reference materials, LGC6019 river water and RTC‐CRM044 soil. The developed method was applied to several matrices such as water, hair, and food samples.  相似文献   

Patterns of rare earth and other trace elements in different size fractions of clays of Campanian–Maastrichtian deposits from the Portuguese western margin (Aveiro and Taveiro Formations)     

Rosa Marques  M. Isabel Prudêncio  M. Isabel Dias  Fernando Rocha 《Chemie der Erde / Geochemistry》2011,71(4):337-347

The Upper Cretaceous (Campanian–Maastrichtian) Taveiro and Aveiro Formations belong to the northern sector of the Lusitanian basin (Portuguese western margin). The Taveiro Formation was deposited in alluvial fans, including mud flow beds, lakes and sinuous rivers. The Aveiro Formation was deposited in a flat region with low hydrodynamics channels, with the formation of a barrier island-tidal system. The reconstruction of this sedimentary basin may be difficult due to its complex architecture. This work aims a methodology to be used in the reconstruction of Cretaceous sedimentary environments of the Lusitanian basin, through the establishment of geochemical patterns of different size fractions of those deposits. Chemical analysis was performed by instrumental neutron activation analysis (INAA), and the mineralogical composition obtained by X-ray diffractometry (XRD). The whole rock and different size fractions (? ≥ 125 μm, 63–125 μm, 20–63 μm, 2–20 μm and ? < 2 μm) of selected samples were studied aiming the rare earth elements (REE) and other trace elements distribution and its correlation with the grain size and mineralogy.The results obtained for the studied Cretaceous sediments showed that REE patterns and other trace elements distribution in the different size fractions may be used as a tool to differentiate deposits within and between sedimentary formations. Within the Taveiro Formation, REE are concentrated in the silt fractions (20–63 μm and 2–20 μm) of the Reveles deposit, and in the clay size fraction of S. Pedro deposit, which is richer in kaolinite. The 1st transition elements, particularly Zn, are correlated with the presence of smectite in the clay fraction of Reveles deposit. In the sand and silt size fractions (>2 μm) of samples from Taveiro Formation correlations were found between: Ga and 1st transition elements, and phyllosilicates; Cs and mica; and Rb and Ba, and K–feldspars.The Bustos deposit (Aveiro Formation) samples are very fine-grained and with a high proportion of the fine silt fraction where REE are concentrated, especially the heavy ones. Incorporation of MREE, Co and U in carbonates of the coarser fraction appears to occur. The abundances of the 1st transition elements, Ga and As, are correlated with phyllosilicates.Significant differences were found in the trace elements patterns of the various analysed size fractions of the Lusitanian basin of Cretaceous sediments, between and even within formations, which can be used as a methodological approach for a fine paleogeographic reconstruction.  相似文献   

Trace element and REE geochemistry of fine- and coarse-grained sands in the Ordos deserts and links with sediments in surrounding areas   总被引：1，自引：0，他引：1  

Wenbo Rao  Hongbing Tan  Sanyuan Jiang  Jiansheng Chen 《Chemie der Erde / Geochemistry》2011,(2):155-170

In addition to mineral analyses, REE and trace element geochemical characteristics of fine- and coarse-grained sands in the Ordos deserts and other sediments in surrounding areas are investigated.Commonly the samples consist of quartz, feldspar and muscovite and less clinochlore, dolomite and ankerite. In few samples muscovite is absent.REE and trace compositions are spatially uniform for the same grain-size sands, suggesting that they could have the same sources or/and were well homogenized. However, fine- and coarse-grained sands in the Ordos deserts show different REE and trace element compositions. Fine-grained sands show higher contents of REE and trace elements than those of coarse-grained sands. They differ in Eu anomalies and (La/Yb)_N ratios although both fractions are characterized by the steep LREE and smooth HREE patterns. The fine- and coarse-grained sands are also distinct in some characteristic element ratios (e.g., Th/Co, La/Sc, Th/Sc and Y/Ni).REE and trace element patterns of the two different grain-size fractions are closely associated with geological properties of individual sources rather than the mineralogical differentiation induced by wind sorting. The coarse-grained sands mainly resulted from sandstone weathering in the Ordos deserts and movements of coarse particles by wind. REE and trace element patterns of fine-grained sands in the Ordos deserts differ from those of sandstones in the Ordos deserts, the alluvial sands in the surrounding mountains and the coarse fluvial sands in the Yellow River. They resemble the fine fluvial sands in the Yellow River. In addition, arid areas of Northwest China such as the Tarim Basin and the Alxa Plateau should not be ruled out as the source of the fine-grained sands in the Ordos deserts because these arid areas reserve plenty of fine-grained sediments and also located in the upwind directions of the Ordos deserts.  相似文献