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1.
岩石—土壤—铁芒萁系统中稀土元素的分布、迁移和累积 总被引：2，自引：0，他引：2
在赣南非稀土矿区和四处不同稀土矿区内取样,用ICP-MS法测定岩石-土壤-铁芒萁系统中15个稀土元素的含量,并对其分布、迁移、累积特征进行了研究。结果表明:稀土元素在岩石、土壤各层含量由高到低的顺序为C(心土层)>A(表土层)>B(底土层)>D(成土母岩);在铁芒萁植物体内的分布规律是:轻稀土元素含量为叶>根>茎>叶柄;重稀土元素含量为根>叶>茎>叶柄;稀土元素演化、迁移的难易是由稀土元素的重轻所决定的;岩-土-芒萁系统各环节间稀土元素的含量模式基本相似,表征元素在岩石→土壤→植物大系统中存在着向量(非均衡性)关系。 相似文献
2.
白云鄂博矿区土壤和植物中稀土元素的分布特征 总被引：2，自引：1，他引：1
白云鄂博矿区是稀土的主要产出地,在矿山开采和选炼等过程中,稀土元素通过迁移、富集等作用进入植物体,研究稀土元素的分布特征和迁移规律,可为白云鄂博矿体闭坑后的生物修复提供数据支持。本文设置了7个土壤采样点,采集铁花、沙蒿、沙打旺、沙朋、青蒿、小叶杨、猪毛菜七种植物,用电感耦合等离子体质谱法测定土壤和植物的根、茎、叶及整株的稀土含量,研究稀土元素在土壤和植物中的分布特征和迁移规律。统计分析结果表明:随着采样区与主矿区的距离增加,土壤样品中的稀土含量逐渐减少;在七种植物中,铁花的稀土含量最高,青蒿最低;对不同植物的整株稀土含量和各部位(根、茎、叶)稀土含量进行多元线性回归分析,叶(或花)的稀土含量在整珠植物中的占比最大。此外在不同季节,植物中的稀土含量基本保持不变,含量较高的稀土元素为Ce(0.0035%～0.020%)、La(0.0012%～0.011%)、Nd(0.0010%～0.0094%)和Pr(0.00036%～0.0046%),其中Ce最高。本研究提出:根据土壤样品中的稀土含量逐渐减少的特征,矿区周围土壤的稀土来源可能是矿石在采、选过程中的扩散造成的;根据植物富集稀土的能力,在矿山闭坑后,可种植富集稀土能力强的植物——铁花,进行矿山生物修复。 相似文献
3.
4.
琼中麻粒岩的成因:稀土元素地球化学制约 总被引：2，自引：0，他引：2
稀土元素地球化学分析表明,琼中麻粒岩可以分为"高Ti"麻粒岩(TiO2含量大于1.0%)和"低Ti"麻粒岩(TiO2含量低于1.0%)两种化学类型."高Ti"麻粒岩以稀土总量高,轻稀土高度富集,轻、重稀土强烈分馏为特征,稀土配分曲线呈右倾单斜型,与本区变基性火山岩的稀土分布特征相似;低"Ti"麻粒岩以稀土总量较低,轻稀土分馏强烈,但重稀土分馏不明显为特征,稀土配分曲线呈重稀土平坦的左高右低型,与许多浅成基性岩的稀土分布特征相似;认为琼中麻粒岩形成于晋宁期的可能性最大.两类麻粒岩的识别,有利于深化对琼中杂岩形成和演化过程的认识. 相似文献
5.
离子吸附型稀土矿是我国南方特色的优质稀土资源,但由于落后的采矿方式和无节制的开采,大量稀土元素(稀土元素+Y,简称稀土元素)被带入环境中,导致稀土矿区周边出现许多环境污染和植被退化问题。乌毛蕨是一种对稀土元素具有较强耐受性和超强富集能力的蕨类超积累植物,能被用于稀土污染土壤或尾矿的生态修复。本研究以离子吸附型矿区表生土壤上生长的稀土超积累植物乌毛蕨及其根际土为研究对象通过化学消解和ICP-MS方法测定根际土、根表、根部、叶柄、叶片中稀土元素的含量,分析土壤–植物体系中稀土元素的空间分布、富集与分异特征;采用顺序提取法测定土壤中不同化学形态的稀土元素含量,同时利用微区X射线荧光光谱(μ-XRF)与扫描电镜能谱分析技术(SEM-EDS),阐明乌毛蕨对稀土元素的吸收与富集机理。化学测试结果表明,乌毛蕨对稀土元素有较强的富集和地上转运能力,富集系数(BF)和转移系数(TF)分别为2.61和2.85;植物器官富集能力顺序为:叶片(1750μg/g)>根部(512μg/g)>叶柄(56.5μg/g);植株整体稀土元素配分模式具有与根际土相似的富轻土元素和Ce负异常特征,不同的是,植株整... 相似文献
6.
白云鄂博是世界最大的稀土矿山,研究白云鄂博矿区土壤及植物等环境介质中的稀土元素和重金属元素的分布特征,可以为调查矿区环境现状提供基础数据,同时为矿山环境修复提供参考依据。本文采集了白云鄂博稀土矿区的土壤、植物,以及背景区本巴台地区的岩石、土壤、牛粪五类样品,采用电感耦合等离子体质谱法（ICP-MS）测定了样品中15种稀土元素（La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Y）及8种重金属元素（Cr、Mn、Ni、Cu、Zn、Cd、Pb、As）的含量,研究这些元素地球化学行为及其在空间上的变化规律。结果表明：①矿区土壤和植物样品均显示出明显的轻稀土富集、重稀土亏损的特征。土壤和植物中含量最高的稀土元素均为Ce,分别达到49.95%及48.55%,与白云鄂博稀土矿富Ce的特征高度一致。②铁花植物的稀土元素总量在空间上呈现出主矿>东矿>东介勒格勒矿段的趋势,与三处矿体本身含矿性变化一致,说明该种植物稀土含量基本受矿体含矿性控制,对生长环境中稀土富集程度指示较准确。③矿区土壤中存在一定程度的Zn （465~778mg/kg）、Cd （1.35~2.23mg/kg）、Pb （181~431mg/kg）累积,其中部分点位Cd、Pb存在超出风险管制值的现象。综上,白云鄂博的矿石、土壤、植物样品均表现出富Ce的特征,且植物稀土含量与其所生长处的矿体含矿性强弱高度相关,三者之间稀土含量特征表现出明显继承性。此外,矿区局部点位土壤存在的Zn、Cd、Pb累积需要引起适当关注。 相似文献
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8.
采用电感耦合等离子体质谱(ICP-MS)方法对兰坪盆地古近系104件细碎屑岩样品进行了稀土元素及微量元素分析,结果显示∑LEE含量较高,轻稀土含量较富集、重稀土含量较亏损,显示出明显的"右倾"型配分模式。根据稀土元素和微量元素特征、w(Zr)-w(Th)、La-Th-Sc、Th-Sc-Zr/10等多种沉积构造背景判别图解及多种交叉分析方法,对兰坪盆地古近系细碎屑源岩构造背景进行了详细研究。利用La/Th-Hf和La/Yb-∑REE判别图解对兰坪盆地古近系源岩属性进行了分析,结果表明:兰坪盆地古近系碎屑源岩主要以上地壳长英质岩石为主,并混有少量基性岩,反映其物源区构造背景为早期为大陆岛弧构造背景,至晚期逐渐过渡为被动大陆边缘构造背景。 相似文献
9.
南海表层沉积物的稀土和微量元素的丰度及其空间变化 总被引：6，自引：0，他引：6
对南海表层沉积物中稀土元素、微量元素丰度和分布特征的研究结果表明,在空间分布上,∑REE与Nb、,Th、Ta、Rb、Ti、Zr、Hf、Cs、Ga、Li等相似,呈显著正相关,反映出这些元素在风化、搬运和沉积过程中地球化学行为非常相似;元素Sr几乎与所有元素都呈负相关,指示其来源或存在形式不同于其他元素,主要来源于生物作用,而在粗粒级的钙质生物贝壳和碎屑中富集.∑REE与Nb、Th、Ta、Rb、Ti、Zr、Hf、Cs、Ga、Li在陆架区具有沿陆分带特点,北部陆架区、中南半岛中东部和加里曼丹岛西北部沿大陆区域富集,与该区陆源河流物质输入及海流的分选作用,造成某些富含稀土和微量元素的重砂矿的富集有关;西南部巽他陆架和东南部岛礁区以及中、西沙附近区域含量较低,与该区域的生源碳酸盐的稀释作用,使粘土矿物相对减少和火山物质对其产生的“稀释“作用有关.南海各海区沉积物和全海区表层沉积物平均值的球粒陨石标准化稀土元素分布模式,总体上与中国大陆沉积物和浅海沉积物相似,而与大洋玄武岩完全不同,反映了南海沉积物与中国浅海沉积物及中国大陆沉积物的物源大致相同,主要来自陆源.南海各海区沉积物稀土元素的球粒陨石标准化配分曲线仍表现出了一定差异,陆架区轻稀土比重稀土明显富集,存在比较明显的Eu负异常,与陆架区相比较,陆坡区和海盆区则轻稀土含量相对降低,重稀土含量有所上升,LREE/HREE从陆架区、陆坡区到海盆区逐渐降低,显示陆架区主要为陆源,而陆坡和海盆沉积物中则有幔源物质加入.稀土元素的大陆壳标准化配分模式大部分较为平坦,少数样品呈轻稀土弱富集型或重稀土弱富集型.说明南海海表层沉积物主要来源于周边大陆.从各海区沉积物稀土元素的大陆壳标准化配分曲线对比来看,陆架区表现为轻稀土富集、重稀土亏损,具一定的铕负异常,深部海盆区则出现明显的中稀土和重稀土的富集,铕异常变弱,与深部海盆区有基性火山物质的加入的地质事实相吻合.南海表层沉积物稀土元素和微量元素总体上呈现出以陆源沉积为主的特征.其元素平均丰度和各参数值都比较接近陆源河流和中国浅海沉积物,而与深海沉积物和大洋玄武岩差别显著,显示南海沉积物虽然受到火山沉积和生物沉积的混合作用的影响,但其物质源仍然主要来自于周缘大陆. 相似文献
10.
南岭地区蕴藏着丰富的稀土资源,是我国稀土矿产的重要产地。南岭稀土矿的成矿,具有一些独特的特征。1.矿化类型多,质量好矿化类型按稀土成因特点划分,有内生型、外生型和变生型等三大类矿床;按矿化岩性划分,有花岗岩型、火山岩型、混合岩型、伟晶岩型、中基性脉岩型和砂矿等;按稀土赋存形式划分,有单矿物型和离子吸附型矿床;按稀土元素组合特征划分,有轻稀土、中稀土和重稀土三大类型。本区的稀土矿质量好,富含经济价值较高的中、重稀土元素,杂质含量低。 相似文献
11.
Geochemistry and biogeochemistry of rare earth elements in a surface environment (soil and plant) in South China 总被引：1，自引：0，他引：1
Li Miao Ruisong Xu Yueliang Ma Zhaoyu Zhu Jie Wang Rui Cai Yu Chen 《Environmental Geology》2008,56(2):225-235
Plants and soils derived from different kinds of parent materials in South China were collected for analyses of rare earth
elements (REEs) by inductively coupled plasma-mass spectrometry (ICP-MS). The distribution patterns and transportation characteristics
of REEs in the soil–plant system were studied. The results show that geochemical characteristics of REEs depend on the types
of soils, soils derived from granite being the highest in REE concentration. In a soil profile, REE concentrations are higher
in B and C horizons than those in A horizon, with Eu negative anomaly and Ce positive anomaly. Plants of different genera
growing in the same sampling site have quite similar REE distribution pattern, but plants of the same genera growing in different
soils show considerable variation in characteristics of REEs. The patterns of the different parts of plant resemble each other,
but the slope of the patterns becomes different. REEs have fractionated when they were transported and migrated from soil
to plant root, stem and leaf, revealing that heavy REEs are relatively less available. REEs distributions in plants are influenced
by the soil they grow in and also characterized by their individual biogeochemical characteristics. Biological absorption
coefficients indicate difference of REE absorption capacity of plants.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Very few studies deal with the biogeochemical behaviors of rare earth elements (REEs) in goldfields. This paper presents the
geochemical and biogeochemical characteristics of REEs within the soil–plant system in the Hetai goldfield, Guangdong, China.
The samples from the goldfield region show anomalies in distribution patterns and behavioral characteristics of REES as compared
with those from the background areas. The REEs in rocks, soils, and plants prove to be much higher than those in the surrounding
regions. The distribution patterns of REEs are characterized by LREE-enrichment and HREE-depletion, with the REE concentrations
in Layer A being the highest. Differentiations between LREEs and HREEs may lead to some extent of negative Eu anomaly in the
soils. Research results demonstrate that the REEs in a soil profile can be transferred and accumulated during the mineral
formation and supergenic geochemical processes, and the anomalies are obviously related to the geological settings for the
REE-bearing ore-forming processes and to the geochemical characteristics of the habitats for the REE-bearing plants. For Dicranopteris dichotoma, the total amount of REEs in the tissues shows an order of leaf > root > stem, while for Pinus massoniana the order becomes root > leaf > stem. The distribution patterns of REEs in Pinus massoniana leaves are similar to those in soils where the plants grow up in the mineralization area. However, in the background areas
the REE distribution patterns for Pinus massoniana stems are similar to those for soils where the plants grow up. Parameters such as biological absorption coefficients and
biological transfer coefficients show the differences in REE absorption features among plants and indicate that REEs can be
transferred among plant organs. The two coefficients can reveal the different survival mechanisms for the two plant species,
which are subject to long-term REE-affected stress conditions in the gold mineralization zone. 相似文献
13.
Yu Guo Yangrong Fu Sen Yan Yi Yang Yuepin Guo Zhengyu Bao 《Environmental Earth Sciences》2012,66(4):1083-1089
Consuming edible plants contaminated by heavy metals transferred from soil is an important pathway for human exposure to environmental contaminants. In the past several decades, heavy metal accumulation in contaminated soil has been widely studied; however, few researches investigated the background levels of metals in plants and evaluated the difference in plants grown in soils produced from different parent rocks. In this study, a systemic survey of heavy metal distribution and accumulation in the soil–pepper system was investigated in an unpolluted area, Hainan Island, China. Levels of Cu, Pb, Zn and Cd were measured in soils and pepper fruits from five representative pepper-growing areas with different soil parent rocks (i.e. basalt, granite, sedimentary rock, metamorphic rock and alluvial deposits). Average concentrations of Cu, Pb, Zn and Cd in pepper fruits were 11.52, 0.84, 8.77 and 0.05 mg/kg, respectively. The concentrations of heavy metals in soils are controlled by the parent materials and varied greatly from in different areas. Heavy metal contents in all pepper samples were lower than the Chinese maximum contaminant levels. The relationship between heavy metals in soils and biological absorption coefficient (BAC) of pepper fruits suggests that the uptake ability of pepper for soil metals depends mainly on the physiological mechanism, while in some cases, the soil types and supergene environment are also important. 相似文献
14.
多目标区域地球化学调查结果显示,江西龙南地区表层土壤Se 平均含量为0.34 mg/kg,总体足硒,局部富硒,且土壤中重金属元素含量处于安全水平?异常查证结果表明,富含硒的基岩是富硒土壤分布的控制因素?在研究区发现天然富硒水稻?富硒大豆优质农产品,其中大豆的富硒率达100%?土壤中有效Se 与总Se 呈极显著的正相关,总Se 含量增大可增加有效Se 量;有效Se 与阳离子交换量(CEC)?N?P呈较显著的正相关,土壤中粘土矿物及有机质对Se 有较强的吸附?络合作用,且土壤中有效Se 主要以亚硒酸盐形式存在?水稻?大豆中Se 的生物富集系数均与土壤Se?N呈显著负相关,与土壤K2O呈显著正相关? 相似文献
15.
土壤中钒的环境地球化学研究现状 总被引：3，自引：0，他引：3
钒是人体必需的微量元素，但过量又会给动植物带来危害。在这里综述了钒的化学性质及其在自然界的分布、土壤中钒的分布规律、化学结合形态及生物地球化学效应，并介绍了土壤中钒的分析方法。在自然界，钒主要分布在基性、超基性岩浆岩和硅质岩、泥岩等沉积岩及土壤中，并且土壤中钒的含量与全铁含量密切相关。钒的分析方法主要是光度法，而电化学分析法是钒的高灵敏度的分析方法。钒的化学结合形态有多种，但只有以可溶态和可置换态形式存在的钒才具有生物可给性。过量钒可导致人体多个器官的癌症疾病等；但低钒会导致心脏、血压、骨骼和味觉的病变。 相似文献
16.
Bo Peng Adam Piestrzynski Jadwiga Pieczonka Meilian Xiao Yaozhu Wang Shurong Xie Xiaoyan Tang Changxun Yu Zhi Song 《Environmental Geology》2007,52(7):1277-1296
The mineralogy and geochemistry of the waste rocks distributed at Taojiang Mn-ore deposit, central Hunan province, China,
were studied using X-ray powder diffraction (XRD), electron microprobe analysis (EMPA) fitted with energy dispersive spectrometer
(EDS) and inductively coupled plasma mass spectrum (atomic emission spectra) ICP-MS (AES), with the aim of predicting the
environmental impacts of weathering of the waste rocks. The mineralogical results from microscope observation and XRD and
EMPA studies show that the waste rock is composed of black shale and minor Mn carbonates. The oxidation of sulfide minerals
such as galena, pyrite and chalcopyrite is accompanied by decomposition of Mn carbonates and K-feldspar during exposure to
atmospheric O2. The geochemical characteristics of major, rare earth elements (REE) and trace elements of the waste rocks also show that
the waste rock can be divided into black shale and Mn carbonate, and both of them are currently under chemical weathering.
The major alkalies and alkaline elements (Ca, Mg, Na, K, Rb, Sr and Cs) and major elements (Fe, S and P) and heavy metals
(Sc, V, Cr, Th, U, Sn, Co, Ni, Cu, Zn, Pb, Mo, Cd, Sb, an Tl) are being released during weathering. The mobility of alkalis
and alkaline elements Ca, Mg, Na, K, Rb, Sr and Cs is controlled by decomposition of Mn carbonates. The dispersion of Cr,
Sc and Th (U) might be related to weathering of K-feldspar, and the release of the heavy metals Co, Ni, Cu, Zn, Pb, Mo, Cd
Sb and Tl is dominated by the breaking of sulfide minerals. The REE of the waste rocks and surrounding soils and the spidery
distribution patterns of heavy metals in the waste rocks, the surrounding soils and the surface waters show that weathering
of the waste rocks and bedrock might be the sources of heavy metal contamination for the surrounding soils and surface water
system for the mining area. This is predicted by the mass-balance calculation by using Zr as an immobile element. Therefore,
it is urgently necessary take measures to treat the waste rocks distributed throughout the area for the local environmental
protection. 相似文献
17.
Rare Earth Element (REE) concentrations in agricultural soil obtained from the Mobile Metal Ion (MMI®) weak extraction technique are compared with soil total concentrations (sodium peroxide fusion followed by acid dissolution) for 118 and 174 agricultural soil samples from Italy and Sweden, respectively. Spatial distribution maps and statistics for both analytical techniques are compared between the two national datasets. In spite of similarity of REE concentration in two countries, the median values of REE is higher than Italy but extreme concentration of REE in Italy is due to young volcanic activities. Extractability of REEs is significantly higher in Swedish soils than in Italian soils. Heavy Rare Earth Element (HREE) in Sweden show higher concentrations compared to Italy in MMI® extraction data where correlate with REE mineralisation. Principal Component Analysis (PCA) is used to elucidate correlations and anomalies in the REE distribution. Results show that there is a clear correlation between REE anomalies and natural factors such as lithology of the underlying bedrock, the presence of mineralisations, pH of soils, climate and precipitation. According to the PCA results, anomalous behaviour of Eu, Ce, Tb and Gd can be explained by the dominant mineralogy of the parent material and the variable affinity of REEs to bind to clay minerals and clay-size particles. 相似文献
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A geochemical soil survey was made over outcropping Cambrian and Lower Devonian formations in the Belgian Ardennes. About 300 soil samples were collected in an area of 2.5 × 1.1 km2.Analysis of rock samples from scarce, but stratigraphically well-known outcrops show that the Cambrian rocks are richer in copper than those of the Lower and Upper Gedinnian (Lower Devonian). The Upper Gedinnian rocks are more nickeliferous than the other horizons.In the well-drained soils, copper and lead distributions permit precise location of the boundary between Cambrian and Lower Gedinnian formations. The nickel distribution seems to be a good stratigraphic indicator for distinguishing Upper from Lower Gedinnian. Zinc distribution seems unrelated to underlying bedrock geology.Regression analysis confirms that the content of Cu, Pb and Ni is essentially a function of lithostratigraphy. However, the distribution of these elements is more influenced by pedological factors in the poorly drained soils. 相似文献
20.
Khadija Semhi Osman A. E. Abdalla Salah Al Khirbash Tabisam Khan Salim Asaidi Sardar Farooq 《Arabian Journal of Geosciences》2009,2(2):143-150
Groundwater samples from six wells and various species of plants from soils developed on ophiolites were collected from an arid area (AlKhod area, Oman) and analyzed for trace elements including rare earth elements (REEs). The distribution patterns of REEs in plants indicated an enrichment in middle REEs (MREEs?=?Sm to Dy) and heavy REEs (HREEs?=?Ho to Lu), when they are normalized to the REE composition of the Post Archean Australian Shale (PAAS), with a significant negative anomaly in Ce and a positive anomaly in Eu. Compared to Oman ophiolites, the REEs in different species of plants are depleted in Ce and enriched in MREEs and slightly enriched in light REE (LREE?=?from La to Nd). Relative to PAAS, the distribution of REEs in groundwaters revealed similar patterns to the REE distribution in plants. The distribution patterns of REEs in plants relative to those in waters are nearly flat. These patterns suggest that the transfer of REEs from soil solutions to the groundwaters in Oman occurs without any significant fractionation. 相似文献