共查询到19条相似文献，搜索用时 140 毫秒
1.
2.
新疆可可塔勒铅锌矿床稀土元素地球化学的初步研究 总被引：1，自引：0，他引：1
可可塔勒铅锌矿矿石和围岩的ＲＥＥ分布模式类似于酸性岩类和泥质碎屑岩类矿石。ΣＲＥＥ值多小于围岩，不同类型矿石ＲＥＥ模式有明显差异。矿石在表生氧化过程中趋于富集轻稀土、贫化重稀土。蚀变围岩ΣＲＥＥ略有增加，Ｅｕ亏损明显。矿石主体形成于开放或近开放体系，含矿热液富含Ｃｌ＾－。蚀变岩石相对于未蚀变岩石、铁帽相对于原生矿石、以及铁帽上方土壤的ＲＥＥ分布特征是找矿评价的ＲＥＥ依据。 相似文献
3.
长江中下游地区若干Cu（Au）,Cu—Fe（Au）和Fe矿床中钙质夕卡岩的稀土元 … 总被引：9，自引：0，他引：9
本区夕卡岩的稀土元素（ＲＥＥ）分布模式表现为富集轻稀土元素（ＬＲＥＥ）的直线型和以Ｃｅ、Ｐｒ或Ｎｄ为峰值的折线型。夕卡岩全岩中的ＲＥＥ分布模式基本上受石了石中的ＲＥＥ的分配行为控制。石榴子石富信ＬＲＥＥ可能是承袭形成它们的初始物中ＲＥＥ丰度和分配行为的反映。石榴子天生中ＲＥＥ分布的不均匀性、石榴子石微裂隙及包裹体中ＲＥＥ的丰度可能是导致直线型和过渡型ＲＥＥ分布模式的主要原因。石榴石石中折线型ＲＥＥ 相似文献
4.
王仲武 《矿物岩石地球化学通报》1995,(4)
自然水中的稀土元素及其表生过程王仲武（中国科学院地球化学研究所，贵阳５５０００２）关键词稀土元素，自然水体，地球化学行为利用稀土元素在不同岩石中的含量和配分模型，可以探讨地质过程和物质来源。同时，不’．伺的麦生水源具有不同酸碱度和含有不同的离于及有机... 相似文献
5.
集中分布于南非金伯利岩和橄榄岩中的石榴石显示出ＲＥＥ正常型和正统曲线型两配分模式。这两种模式被解释为富集ＨＲＥＥ的熔体或流体对古老地幔石榴石交代的结果。在本文的模式中，交代作用的进行与石榴石－流体的分配系数ＫＤＳ的变化相一致，即ＫＤＳ随着ＬＲＥＥ、ＭＲＥＥ到ＨＲＥＥ的富集系数增大而增，这样将ＲＥＥ分成三组。 相似文献
6.
REE示踪沉积物物源研究进展 总被引：101，自引：0，他引：101
ＲＥＥ作为一种重要的沉积物物源示踪剂运用很广。在介绍了ＲＥＥ性质的基础上，对海水、河水、沉积岩、河流及边缘海沉积物中的ＲＥＥ元素丰度与配分模式特征进行了深入综述，概述了影响和控制ＲＥＥ丰度、模式及分馏特征的主要因素；论述了ＲＥＥ的物泊示踪意义以及在国内外应用情况与存在问题：源岩风化对ＲＥＥ分馏的影响；颗粒运及沉积时水动力分选对ＲＥＥ分馏可能造成的影响，即不同粒级中的ＲＥＥ不同的丰度与配分模式和碎屑 相似文献
7.
长江中下游地区若干Cu(Au)、Cu-Fe(Au)和Fe矿床中钙质夕卡岩的稀土元素地球化学 总被引：25，自引：2，他引：23
本区夕卡岩的稀土元素（ＲＥＥ）分布模式表现为富集轻稀土元素（ＬＲＥＥ）的直线型和以Ｃｅ、Ｐｒ或Ｎｄ为峰值的折线型。夕卡岩全岩中ＲＥＥ分布模式基本上受石榴子石中ＲＥＥ的分配行为控制。石榴子石富集ＬＲＥＥ可能是承袭形成它们的初始物中ＲＥＥ丰度和分配行为的反映。石榴子石中ＲＥＥ（尤其是Ｌａ）分布的不均匀性、石榴子石微裂隙及包裹体中ＲＥＥ的丰度可能是导致直线型和过渡型ＲＥＥ分布模式的主要原因。石榴子石中折线型ＲＥＥ分布模式可能受石榴子石晶体化学和晶体结构的控制。具有这种ＲＥＥ分布模式的钙铁－钙铝榴石可能代表相对平衡条件下岩浆结晶分异产物。 相似文献
8.
南岭地区高度演化花岗岩类的稀土元素模型 总被引：1，自引：0，他引：1
本文应用现有的理论模型和矿物／熔体分配系数讨论南岭地区高度演化花岗岩类的ＲＥＥ模型，包括重稀土富集型和稀土亏损型。在花岗岗岩浆分异演化过程中，副矿物（尤其是稀土矿物）的晶出种类，顺序和物理化学条件是控制ＲＥＥ强烈分馏的关键因素。ＲＥＥ分布型式不能简单地作为鉴别岩石成因的标志。 相似文献
9.
试论有机质在华南花岗岩风化壳REE溶出、迁移和富集中的作用 总被引：13，自引：1，他引：13
通过实验研究，论证了花岗岩风化壳中存在有机质，含有丰富的一元脂肪酸和二元脂肪酸，腐殖酸及多糖化合物。ＲＥＥ能以ＲＥ（Ｈ２Ｏ）配位离子从原岩溶出，一些有机介质和无机介质有助于ＲＥＥ从原岩溶出、迁移，其中以脂肪酸溶出量最高。溶出过程配位反应与水解反应同时出现，溶出和在风化壳中保留同时进行，反应受ｐＨ控制。风化壳中ＲＥＥ存在有机结合形态，可能与长链酸或腐殖酸关系比较密切。活性态ＲＥＥ除了与粘土矿物关系密切外，可能与多羟基化合物或多糖有关。 相似文献
10.
金的表生地球化学研究现状 总被引：3，自引：0，他引：3
金的表生地球化学演化行为，表现为其成色提高，品位变富，金颗粒增大等明显的地质规律，次生矿物、如赤铁矿、针铁矿及粘土矿物等，对金具明显的表生吸附作用，特别是２Ｍ１型伊利石与金的表生富集作用关系密切，除腐殖酸以外，脂肪酸对金的表生富集显著；无机酸的作用与矿床氧化剖面中的Ｅｈ，ｐＨ环境共同制约着金的表生集散规律，干旱气候区矿床氧化带中金、银呈双峰富集，而在潮湿区呈单峰富集，金的物理特性是金的表生形态复杂 相似文献
11.
Geochemistry of Rare Earth Elements in the Ocean 总被引：4，自引：0，他引：4
This work briefly outlines modern ideas on geochemistry of rare earth elements (REE) in the ocean. Sources of REE and chemical properties of these elements, which govern their migration ability in natural processes, are considered. The REE behavior in the river water–seawater mixing zone is analyzed. The fractionation of dissolved and suspended REE in oceanic water in both aerobic and anaerobic conditions is also considered. It is shown that the variability of REE composition in pelagic sediments reflects the fractionation of these elements in the oceanic water as a consequence of material differentiation in the ocean. The REE distribution in terrigenous, authigenic, hydrothermal, and biogenic constituents of sediments, such as clay, bone debris, barite, phillipsite, Fe–Mn oxyhydroxides (ferromanganese nodules and micronodules), Fe–Ca hydroxo-phosphate, diatoms, and foraminifers, is considered. 相似文献
12.
Rare earth elements in the sedimentary cycle: A summary 总被引：2，自引：0，他引：2
David Z. Piper 《Chemical Geology》1974,14(4):285-304
The relative and absolute concentrations of rare earth elements (REE) in authigenic and biogenic phases of deep-sea sediments are quite different. Competition between these phases for REE has resulted in fractionation from the parent material, the latter consisting predominantly of terrigenous material, but with a contribution from marine volcanism. The strongest feature of this fractionation is a depletion of Ce, relative to La, in CaCO3, opalline silica, phillipsite, phosphorite, barite, and montmorillonitic clays; and a Ce enrichment in Fe/Mn nodules. The distribution of REE in different masses of seawater strongly reflects their fractionation in sediments. Whereas the relative concentration of REE in rivers resembles that of shale, their removal from seawater by authigenic and biogenic phases results in: (1) a decrease of their total concentration; (2) a depletion of Ce; and (3) an enrichment of heavy REE relative to light REE. The order of fractionation for water masses in the Atlantic Ocean is:Antarctic intermediate water > North Atlantic deep water > Antarctic bottom water> shelf water > river water ～ shale.The shale-normalized pattern for the sum of REE in the authigenic and biogenic phases of pelagic sediment and in seawater resembles that of an admixture of shale and basalt corresponding presumably to the realtive inputs from continents and marine volcanism respectively. The estimated rate of accumulation of each REE in the sediment, however, is approximately 12 times the estimated rate of input of REE from these two sources. 相似文献
13.
通过对内蒙古额济纳盆地小狐山剖面沉积物中酸溶组分稀土元素含量及其相关指标、分布模式的分析,讨论了剖面中稀土元素指标δCe－ΣREE与沉积相、沉积环境之间的关系。分析结果表明剖面沉积物酸溶组分中稀土元素丰度均值为7.24μg/g(不包括Y),其中LREE含量占稀土总量的88.67%; 且各层的稀土分布模式均为轻稀土适度富集缓右倾斜型、Eu呈负异常模式,但各相位地层的LREE富集程度与分配模式存在差异。由于小狐山剖面中沉积地层的自身岩性、沉积粒径、矿物结构组成以及气候环境变化等因素均可能会引起REE分异。因此,通过δCe－ΣREE图并结合三次回归曲线,可以很好地将不同沉积相得物质有效的区分开来。小狐山剖面除极少数的几个样品(水下沉积砂)之外,其余的均落在三次多项式回归曲线上部; 而风成砂层则几乎全部落在回归曲线之下; 此外,对于风沙－河流作用下的混合样品也有较好识别,河流过渡相的样品则分布在曲线上或与之相邻近。此研究结果得到了柴达木贝壳堤沉积物的REE数据的验证,运用此方法可以为直观的判别剖面中的不同沉积相,并为定量化划分地层提供依据。 相似文献
14.
Rare earth elements (REE) concentrations of Archean and Proterozoic chemical sediments are commonly used as proxies to study secular trends in the geochemistry of Precambrian seawater. In addition, similarities in the REE signatures of Archean chemical sediments and modern seawater have led researchers to argue that some Archean rocks originated as biochemical precipitates (i.e., microbial carbonates) in shallow marine (e.g., peritidal) environments. However, terrestrial waters, including river water and groundwater, also commonly exhibit REE fractionation patterns that resemble modern seawater. Here, we present the seawater-like REE data for groundwaters from central México as additional evidence that these patterns are not unique to the marine environment. The shale-normalized REE patterns of the groundwaters are compared to those of modern seawater (open ocean and nearshore), Holocene reefal microbial carbonates and corals, and Archean chemical sediments using statistical means (i.e., ANOVA and Wilcoxon analyses) in order to quantify the similarities and/or differences in the REE patterns. Shale-normalized (SN) Ce anomalies and measures of REE fractionation [i.e., (La/Yb)SN, (Pr/Yb)SN, (Nd/Yb)SN, and (Gd/Yb)SN] of the central México groundwater samples are statistically indistinguishable from those of modern seawater. Moreover, except for differences in the Ce anomalies, which are lacking in Archean chemical sediments, the REE patterns of the central México groundwaters are also statistically similar to REE patterns of Archean chemical sediments, especially those of the 3.45 Ga Strelley Pool Chert. Consequently, we suggest that without additional information, it may be premature to unequivocally conclude that Archean chemical sediments record REE signatures of an Archean ocean. 相似文献
15.
北京平原沉积物稀土元素地球化学特征及物源意义 总被引：2，自引：0，他引：2
文中总结了北京平原永定河、潮白河流域钻孔沉积物中稀土元素分布特征,两流域沉积物稀土元素总量∑REE、轻重稀土比(LREE/HREE)及轻(La/Sm)N、重(Gd/Yb)N稀土分馏特征差异较为显著。粒度对沉积物稀土分布(总量、轻重稀土比及分馏特征)有一定影响;各流域沉积物均表现为轻稀土相对富集、弱Eu负异常的球粒陨石标准化曲线。细颗粒沉积物稀土分馏特征(La/Yb)N有较好的物源示踪意义。根据沉积物(La/Yb)N值对永定河、潮白河交互沉积区不同深度沉积物进行了物源示踪,不同深度上沉积物来源不同。此外,同一流域上、中、下游沉积物稀土分馏特征不同。常量元素Al2O3/Fe2O3与稀土元素(La/Yb)N划分结果相符,但精度低于稀土元素物源分析。 相似文献
16.
The aim of this paper is to study the REE geochemistry of the Shenzhen Bay (SZB) and Dapeng Bay(DPB) modern sediments, discuss their REE distribution patterns, reveal the REE geochemical difference between the two bays which share the same material source but are deposited in different sedimentary environments, and expound their dynamic changes.It can be concluded that the SZB and DPB sediments are essentially of continental source.Their REE distribution patterns are quite different from those of Pacific pelagic sediments, but are very similar to those of South Chi-na granites.Because of different sedimentary environments prevailing in the SZB and DPB, some REE fractionation would have taken place in the sediments of the two bays. 相似文献
17.
在2007年底至2008年初的枯水期间,系统采集了中国东部流域面积和径流量较大的33条河流沉积物、悬浮颗粒物和水样,采用等离子质谱法、X荧光光谱法等方法测定了14种稀土元素含量以及常量组分和水体pH值等理化指标。研究发现中国河流稀土元素浓度总体高于世界均值,且南方河流沉积物、悬浮物稀土元素含量高于北方河流,南方河流悬浮物态中稀土、重稀土呈现一定程度的相对富集,与我国上地壳稀土丰度和稀土矿产种类的南北分异相吻合。展示了以中国东部泥质岩稀土元素丰度标准化后的稀土配分模式及Ce、Eu异常特征,发现河流沉积物的中、重稀土元素相对富集,悬浮物轻稀土相对富集,溶解相重稀土富集的特征;北方河流溶解相稀土元素浓度明显大于南方河流,且除小清河外,溶解相Eu不同于沉积物与悬浮物而呈强烈的正异常,主要与河水理化性质影响下的稀土分异有关。研究发现小清河等少数河流沉积物中稀土元素为异常高值,经Al标准化处理、计算拟合剩余值后,认为小清河等河流稀土元素已受人为污染的影响。 相似文献
18.
长江与黄河沉积物REE地球化学及示踪作用 总被引：66，自引：4，他引：62
长江与黄河沉积物的稀土元素（ＲＥＥ）组成特征不同。长江沉积物ＲＥＥ含量较高,元素含量变化也大于黄河样品;球粒陨石标准化模式表明长江沉积物的（Ｌａ／Ｌｕ）Ｎ、（Ｌａ／Ｙｂ）Ｎ、（Ｇｄ／Ｙｂ）Ｎ的值也相应地比黄河沉积物中的高１０％左右,分布曲线均呈明显的石倾状,轻重稀土分馏明显,相对富集ＬＲＥＥ。且长江样品比黄河样品更富集ＬＲＥＥ,但Ｅｕ亏损不及黄河样品;两者的北美页岩标准化曲线均呈平坦稍右倾状,具有 相似文献
19.
REE geochemistry of the recent playa sediments from the Thar Desert, India: An implication to playa sediment provenance 总被引：3，自引：0，他引：3
The playas (saline lakes) situated in the Thar Desert, north-west India, provide prominent examples of alkaline brine and varying assemblages of detrital and evaporite mineralogy. The eastern margin of the desert is relatively semi-arid, whereas the central to western region is arid to hyper-arid in nature. Rare earth elements (REEs) systematics in the sediments of nine different playas of the Thar Desert were studied to understand the provenance of the sediments and the intensity of chemical weathering in the region. Based on the REE patterns, fractionation of light REE (LREE) (La/Sm)N and heavy REE (HREE) (Gd/Yb)N, and Eu anomaly (Eu/Eu*), the upper continental crust normalised playa sediments are divided into two different groups. The eastern margin playa sediments show homogeneous REE contents, relatively positive Eu anomaly and depleted HREE values, whereas the western arid core playa sediments have highly variable REE contents, relatively negative Eu anomaly and similarly fractioned LREE and HREE patterns. The dissimilarity in the degree of HREE fractionations both in the eastern and western playa sediments is attributed to the differential distribution of minerals, depending upon their resistance to chemical weathering. It is believed that the relatively higher abundance of REE bearing heavy minerals and the presence of higher amounts of evaporites influence the large variation of REE distribution and enriched HREE in the western playa sediments. Apart from the relatively higher abundance of heavy minerals, the presence of rock fragments of variable petrographic character and roundness mirror the lower rock–water interaction in the arid western region. The presence of well-rounded metamorphic rock fragments and minerals, sourced from the eastern margin Aravalli mountains, indicates that the playas of the entire desert get the detrital and dissolved material mainly from the Aravalli mountains. Additionally, the western playas receive sediments from their surrounding Proterozoic and Mesozoic formations. This interpretation is supported by the presence of angular rock fragments of basalt, rhyolite and limestone in the western playas. 相似文献