江西雅山黄玉锂云母花岗岩中铯矿物的电子探针研究

江西宜春雅山花岗岩是典型的高度分异型稀有金属花岗岩。通过对其最晚期花岗岩———黄玉锂云母花岗岩的钻孔样品和近地表样品的研究,发现岩体中主要有两种铯矿物:铯沸石和富铯锂云母。铯沸石是第一次在花岗岩中发现,其产状主要有两类:一类包裹于石英中,颗粒小,只有2～10μm,单个颗粒成分均匀,Si/Al比值和Poll值(%)犤=100×Cs/(Na+K+Rb+Cs)犦分别为2.13～2.65和57～89;另一类赋存于钠长石晶隙间,颗粒大,多为几百μm,单个颗粒成分不均匀,Si/Al比值和Poll值分别为2.20～2.45和75.6～88.2。富铯的云母类矿物分布较普遍,主要呈四种产状,分别为钾长石雪球中的带状富铯锂云母、云母边部的环边富铯云母、叶脉纹理状富铯云母和主矿物中的富铯云母包裹体,并根据成分中Si/Al比值和Cs的摩尔分数(%)犤=100×Cs/(Cs+K)犦,将富铯的云母类矿物分为含铯锂云母、富铯锂云母和铯锂云母三类,其中Cs替代K,Cs完全替代K形成的铯锂云母可能是锂云母系列中的铯端员新矿物。钻孔样品中的富铯云母类矿物以带状结构和环边结构最为发育,且成分主要属于含铯锂云母和富铯锂云母这两个部分,而近地表样品中则以环边结构和叶脉纹理状结构为特征,成分多为铯锂云母。铯沸石和富铯云母的产状及地球化学特征均表明,雅山岩体原始岩浆中碱金属经     

福建南平31号花岗伟晶岩脉中绿柱石的电子探针成分与成因

福建南平花岗伟晶岩是中国重要的稀有金属花岗伟晶岩之一,其中31号脉是分异程度最高、稀有金属成矿作用最重要的岩脉,绿柱石是其中最主要的铍矿物。利用电子探针和背散射电子成像技术对该岩脉中绿柱石进行了较系统分析。结果表明,南平31号花岗伟晶岩中绿柱石可分为原生绿柱石和晚期绿柱石。原生绿柱石形成于早期岩浆阶段,与造岩矿物石英、白云母、钠长石、锂辉石共生。晚期绿柱石与原生绿柱石密切伴生,是富铍流体沿原生绿柱石的边缘结晶而成,或热液沿原生绿柱石的解理、裂隙或孔隙度较大部位进行交代的产物。电子探针成分分析显示,南平31号花岗伟晶岩脉中原生绿柱石除含主要化学成分SiO2,Al2O3和BeO外还含Na,Cs,Fe,Mg等元素;FeO,MgO,Na2O和Cs2O的最高含量分别为0.28%,0.89%,1.36%和3.92%。总体上,从I带至IV带,原生绿柱石的FeO和MgO含量逐渐降低,Na2O和Cs2O的含量逐渐升高,尤其是Cs2O的含量变化较大。III—IV带中少量原生绿柱石分布于锂辉石中,具有富FeO和MgO的特征。晚期绿柱石的Cs2O含量较低,可能是由于铯沸石和南平石（铯云母）等铯矿物的结晶,导致晚期熔体-热液中相对贫铯,而热液流体与富铯绿柱石之间可能存在铯的化学再平衡。     

河北兴隆M111稀有金属花岗岩体地质和岩石学特征

本文报道了河北燕山地区一个稀有金属花岗岩体的地质特征、岩石学、矿物学和岩石化学特征.这个两次侵入形成的复式岩体,Rb-Sr同位素年龄171Ma。造岩矿物为石英、钠长石、微斜长石、含锂云母。化学成分铝过饱和富钠偏碱性.发育良好的岩性垂直分带,岩石结构、矿物和化学成分均呈规律性的变化.岩浆成分向富钠富稀碱富挥发分的方向分异演化导至Nb、Ta、Li、Be、Rb、Cs等稀有金属矿化。     

四川甲基卡X03号脉接触变质岩中Cs等稀有元素赋存状态及其综合利用建议

【研究目的】甲基卡稀有金属矿区是中国规模最大的花岗伟晶岩型稀有金属矿床富集区,X03号脉是近年来该矿区发现的以锂为主的超大型稀有金属矿床,在其围岩中发育电气石、堇青石化接触变质带,形成的蚀变岩具有Li、Rb、Cs等稀有金属矿化。Cs是重要的稀有金属元素之一,寻找更多可利用的铯资源成为当务之急。【研究方法】对钻孔岩芯中电气石角岩、堇青石化片岩等接触变质岩样品进行了稀有元素含量分析,并采用LA-ICP-MS对电气石、堇青石、黑云母、白云母等变质矿物进行了单矿物微区分析。【研究结果】接触变质岩中Li、Rb、Cs具有较高的含量,其平均值分别为0.296%、0.067%、0.052%,均达到综合利用的边界品位或最低工业品位,其特征与蚀变岩型铯云母岩矿床极其相似。Cs元素主要以类质同象的形式赋存于黑云母之中,是引起接触变质岩石Cs元素富集的主要原因。【结论】在X03号脉的进一步勘查中,应对接触变质岩石中稀有金属资源,特别是Cs资源进行评价,并对其进行综合利用。创新点：分析了X03号脉接触变质岩中Cs等稀有元素的含量,指出了Cs元素主要以类质同象的形式赋存于黑云母之中,应对其进行综合利用。     

云母:花岗岩-伟晶岩稀有金属成矿作用的重要标志矿物

云母是花岗岩、伟晶岩中的重要造岩矿物,不仅是整个岩浆阶段的结晶产物,而且也是热液过程的参与者。作为层状硅酸盐矿物,层间或八面体位置上可容纳锂、铷铯、锡、铌钽等稀有金属。本文结合前人研究积累和作者近年来的研究成果,阐述了云母作为一个重要的稀有金属成矿标志矿物的矿物学特征。铁锂云母-锂云母是稀有金属成矿作用中重要的锂矿物,同时云母中锂含量可以反映花岗岩的分异程度。铷、铯可以置换云母层间钾,在高演化花岗岩、伟晶岩中可以形成铷、铯为主的云母(既可以是锂云母系列,也可以是黑云母系列)。黑云母是稀有金属花岗岩中一个特殊的矿物。准铝质含锡花岗岩中黑云母锡含量可达100×10~(-6),其锡含量可以指示其锡成矿能力。稀有金属花岗岩中,常见的是铌钽氧化物矿物。但是最近研究发现,黑云母中铌可以超常富集(超过1000×10~(-6)),成为稀有金属花岗岩中最重要、甚至唯一的铌矿物,形成一种以富铌黑云母为特色的新类型稀有金属花岗岩,并可能代表了一种新型的潜在铌资源。基于云母在花岗岩中的重要性和结构的特殊性,今后要利用微区成分和结构分析技术,加强对云母中稀有金属晶体化学的研究,以及进一步揭示云母对稀有金属成矿的特殊重要意义。     

开展分散元素地质工作的若干问题

目前,稀有金属在科学技术发展方面起着重要的作用,象核技术、原子能工业、自动控制、遥测裝置、喷气飞机、火箭……等都需要稀有金属,因而目前工业的发展,对稀有金属的需求是非常迫切的.在稀有金属中有12种金属称为分散元素(锗、镓、铟、铊、镉、铼、硒、碲、钪、铪、铯、铷).它们在自然界并不形成独立的工业矿物或矿床,而主要是在其它有用矿物中旱杂质出现.在冶炼其它有用矿物时順便回收的.因而在一般矿产的普查勘探工作中,     

福建某稀有金属伟晶岩矿田地质地球化学特征

福建某稀有金属伟品岩以富铌、钽而著称,并含锂、铍、铷、铯等稀有金属。本文着重对该区地质特征、控矿构造、伟晶岩类型、成矿阶段划分、空问分布规律、稀有元素地球化     

福建溪源头伟晶岩及围岩中的云母特征

作者对福建溪源头稀有金属花岗伟晶岩及其围岩中的40余个云母样品进行了成分、物性、结构及热性质的综合研究。溪源头伟晶岩之不同组合带中产出的云母均为2M_1型含铷白云母,云母中含铷、铯而贫锂、贫氟。云母斜长变粒岩中的白云母为含铁白云母。其中钛、镁含量偏高。石英云母片岩中之3T铝黑鳞云母的八面体阳离子占位介于二八面体和三八面体之间。该云母以富稀碱元素及挥发分为其特征。溪源头云母的成分及种属反映了形成它的地质环境特点,与围岩性质及成矿类型有关,可作为稀有金属伟晶岩矿床的标型矿物,可以用作找矿标志。     

西峡县陈阳坪铍铷矿地质特征

在东秦岭西官庄-镇平断裂带陈阳坪地区进一步发现稀有金属矿产后,为了解铍铷矿床特征,对陈阳坪花岗伟晶岩型铍铷矿石矿物电子探针特征及矿区地质等进行了综合分析研究.本区发现伟晶岩脉11条,铍铷矿体4条,矿体长105～1100 m,厚4.26～7.00 m,BeO品位:0.035％～0.0445％,Rb2O品位:0.046％～0.123％.矿石有用矿物为钾长石、白云母、绿柱石、石榴子石等,钾长石晶体裂隙中可见绿柱石,为含铍的重要矿物;白云母集中于花岗伟晶岩中带,铯榴石不均匀出现于伟晶岩边部、构造裂隙、钾长石颗粒间隙,为含铯铷矿物.据矿石矿物电子探针分析,矿石中的铷主要赋存于钾长石、白云母矿物.产于晋宁期花岗伟晶岩中的铍铷稀有金属矿,矿体受伟晶岩脉控制,晋宁期的岩浆活动为本区铷矿、稀有元素形成提供了丰富的物质来源,经后期构造及岩浆热液活动使岩体中的铍、铷元素活化富集形成稀有金属矿床.在矿区东部及南部也存在类似地质构造特征,陈阳坪地区花岗伟晶岩的研究成果对豫西南铍铷等稀有金属矿产取得进一步找矿突破具有一定意义.     

海南儋州铯铷稀有金属矿床地质特征

海南儋州铯铷矿床为近期新发现的规模较大的稀有金属矿床.本文结合区域地质和矿区地质构造,阐述了矽卡岩型铯铷矿床和云英岩型铷矿床的矿石质量、化学成分和矿体特征,简单分析了矿床的成矿机制,为该区域的地质找矿提供了新的方向.     

Cs-dominant polylithionite in the Koktokay#3 pegmatite,Altai, NW China: in situ micro-characterization and implication for the storage of radioactive cesium

Except forming two Cs-rich minerals like pollucite and londonite, cesium generally occurs in trace amounts in potassium-bearing minerals owing to its very low Clarke value and large ionic radius. However, in the Koktokay#3 pegmatite (Altai, NW China), lepidolite is extremely enriched in cesium (typically 21–26 wt% Cs₂O). Cs-enriched lepidolite is restricted to the inner of the pegmatite, where four types of occurrence are characterized by using in situ techniques (EMP: electron microprobe, micro-XRD: micro-area X-ray diffractometer and Raman probe: micro-area Raman spectrometer) as: (1) outer zones on Cs-poor lepidolite cores; (2) fine overgrowths on muscovite veinlets; (3) veinlets in Cs-poor lepidolite and (4) veinlets in elbaite. There is an inverse correlation between K and Cs and in terms of ^VIAl versus Cs/(K+Cs), the Cs-dominant micas are an analog of the Li-rich mica polylithionite. Micro-XRD patterns and micro-Raman spectra indicate that Cs-dominant polylithionite structurally corresponds to minerals of the lepidolite series. According to its distribution and compositional characteristics, the Cs-dominant polylithionite seems to have formed at the magmatic to hydrothermal transition stage of pegmatitic magma evolution as a result of marginal replacement of early-formed lepidolite by Cs-rich fluids. Alternatively, it may have formed through direct precipitation from Cs-rich fluids. The results of the present study have important implications for the storage of nuclear waste in that Li mica such as polylithionite is a good candidate for immobilizing high-level radioactive cesium waste.     

Minerals and design of new waste forms for conditioning nuclear waste

Safe storage of radioactive waste is a major challenge for the nuclear industry. Mineralogy is a good basis for designing ceramics, which could eventually replace nuclear glasses. This requires a new storage concept: separation-conditioning. Basic rules of crystal chemistry allow one to select the most suitable structures and natural occurrences allow assessing the long-term performance of ceramics in a geological environment. Three criteria are of special interest: compatibility with geological environment, resistance to natural fluids, and effects of self-irradiation. If mineralogical information is efficient for predicting the behaviour of common, well-known minerals, such as zircon, monazite or apatite, more research is needed to rationalize the long-term behaviour of uncommon waste form analogs.     

海岸带地区137Cs沉积剖面类型划分及其意义

作为一种人工核素,<'137>Cs年代学方法已在海岸地区得到广泛应用,并成为重建现代地质过程的重要方法.搜集了海岸带地区报道的200余组<'137>Cs沉积剖面数据(其中中国海岸带地区121个站住,其它地区100余站位),通过对<'137>Cs沉积剖面形态的分析.并与理想<'137>Cs沉积剖面对比研究,结果显示,海岸...     

海岸带地区~（137）Cs沉积剖面类型划分及其意义

作为一种人工核素,137Cs年代学方法已在海岸地区得到广泛应用,并成为重建现代地质过程的重要方法。搜集了海岸带地区报道的200余组137Cs沉积剖面数据（其中中国海岸带地区121个站位,其它地区100余站位）,通过对137Cs沉积剖面形态的分析,并与理想137Cs沉积剖面对比研究,结果显示,海岸带地区137Cs沉积剖面表现为以下6种主要类型：①不连续137Cs曲线、②无特征峰型的连续137Cs曲线、③特征峰型偏下的连续137Cs曲线、④特征峰型偏上的连续137Cs曲线、⑤比活度向下增大的137Cs曲线和⑥比活度向下减小的137Cs曲线。各种类型的沉积剖面反映的沉积环境是多样的;侵蚀作用、混合作用和沉积物供给变化是控制137Cs沉积剖面的主要因素;同时,137Cs定年的取样要尽量做到无扰动,数据解释要考虑到取样分辨率的影响;在没有大气沉降监测的海岸带地区,其附近沉积环境相对稳定地区的137Cs沉积剖面可作为潮间带、浅海区的背景参考值。     

Modelling of Cs sorption in natural mixed-clays and the effects of ion competition

Cs migration in the environment is mainly controlled by sorption onto mineral surfaces, in particular on clay minerals. With the objective of designing a geochemical reactive barrier to treat ¹³⁷Cs accidental pollution in an industrial waste repository, different natural clayrocks were studied to analyse their capacity to retain Cs.The simple semi-empiric K_d-approach for experimental data analysis, is unsatisfactory to describe the variability of sorption upon chemical changes. Indeed, due to the high salinity of the site, the effects of competitive ions must be evaluated and quantified. Thus, the development of sorption models, capable of reproducing experimental data obtained under conditions representative of the contaminated site, and applicable to reactive transport studies, is needed.In this study, a model for Cs sorption, which takes into account the main mineralogy of the sorbent, the composition of the natural water (and ion competition) was successfully applied to interpret the non-linear Cs sorption under natural conditions.The selectivity coefficients of Cs with respect to the most important cations present in the site water (Na, K, NH₄, Ca) were derived by means of experiments in single clay minerals and synthetic mono-component solutions. Then, these parameters were tested in systems of increasing complexity.Considering the mineralogical composition of raw materials, it was shown that the principal contribution to Cs sorption is given by the mineral illite, while smectite starts to be relevant only at very high Cs loadings. Kaolinite, even in concentrations around 10 wt% of the clayey fraction, played only a minor role.With respect to the solution composition, the model was able to predict Cs sorption in electrolyte concentrations up to twice than that of seawater and up to 500 mg/L NH₄⁺. The effect of highly competing ions, especially NH₄⁺ and K⁺, on Cs retention is more important at low ionic strengths and low Cs loadings, where adsorption is dominated by illite selective frayed edge sites, FES. Divalent cations are not especially relevant as competing cations for Cs.     

Reversible ion-exchange fixation of cesium-137 leading to mobilization from reservoir sediments

The radioactive fission product, ¹³⁷Cs, has been observed to mobilize from bottom sediments of two South Carolina reservoirs during summer thermal stratification and hypolimnetic anoxia. Mobilization is attributed to ion-exchange displacement of ¹³⁷Cs from sediments by cations such as NH⁺₄, Fe⁺² and Mn⁺² released under anaerobic conditions.Three types of ¹³⁷Cs binding sites to sediment clay minerals are identified: 1) surface and planar sites from which ¹³⁷Cs is generally exchangeable by all cations studied (Na⁺, NH⁺₄, H⁺, Cs⁺, Ca⁺², Mg⁺², Fe⁺², and Mn⁺²); 2) wedge sites where ¹³⁷Cs exchange is sterically limited to cations of similar size and charge (NH⁺₄, Cs⁺, K⁺, and perhaps H₃O⁺); 3) interlayer sites from which ¹³⁷Cs is not readily exchanged. More than 15 years after final ¹³⁷Cs inputs, the reservoir sediments we studied showed the following percentage distribution of sites: 2 to 9% surface sites, 6 to 13% wedge sites, and 78 to 85% interlayer sites. In contrast, lake and stream sediments near Oak Ridge, Tennessee receiving ¹³⁷Cs inputs more than 20 years earlier had greater than 99% of their ¹³⁷Cs associated with non-exchangeable interlayer sites. The difference is attributed to the paucity in the South Carolina sediments of weathered micaceous clay minerals with their abundant interlayer sites. Such interlayer deficient clays are dominant in the Atlantic and Gulf coastal plains of the United States and elsewhere. This suggests that ¹³⁷Cs will be physically and chemically more mobile in such areas as well as more biologically available. Mobility will be enhanced in regimes where cation inputs favoring ¹³⁷Cs exchange occur. Subsurface waste disposal sites where anaerobic conditions develop with NH⁺₄ production and Fe⁺² and Mn⁺² release might be such a regime.     

核废物处置安全评价的地质类比研究

本文简要论述了利用天然地质类似物（或类比体），类比评价核废物处置系统的安全性能。地质类比研究是安全评价核废物处置系统的重要方法之一，也是地质学科的新研究领域。目前已有的地质类比研究对象主要有火山玻璃，陨石玻璃，粘土矿物，铁陨石，铜矿床，铀矿床，含含Ｔｈ和ＲＥＥ的铁矿床，天然核反应堆（一种特殊的铀矿床）和火成岩接触带等。最后对我国今后从事同类研究提出了若干建议。     

A note on partition coefficient distributions

Much interest has been generated in assessing the possible risks of contamination for humans and marine life resulting from the dumping of nuclear waste in Arctic Seas by the former Soviet Union. Models are being used to predict the transport of radionuclides released from the dumping grounds. A key parameter in these models is the partition coefficient representing the uptake potential of marine sediments and seawater for radioactive contaminants. Partition coefficients are dependent upon the independent variables of sediment concentration and the sediment/water radionuclide distribution coefficients. Modelers must use estimated average values for the independent variables because data for these variables are lacking for the Arctic environment. In this note, we illustrate the differences between assuming that partition coefficients can be computed solely from the average values of the independent variables vs. exact probability distributions, and illustrate the technique for one of the radioactive contaminants,¹³⁷Cs. In general, errors in the sediment partition coefficient can be as high as 67% using average values; for¹³⁷Cs. the error is about 37%.     

137Cs示踪农耕地土壤侵蚀速率模型的比较研究

^137Cs示踪技术广泛地应用于农耕地土壤侵蚀研究,目前已建立了许多运用^137Cs估算土壤侵蚀速率的模型。这些模型主要分为两类：经验模型与理论模型。其中理论模型中的质量平衡模型应用较多。质量平衡模型主要有：Walling模型、张信宝模型、杨浩模型和周维芝模型。重点讨论这4种质量平衡模型的异同。详细阐述了这四种模型的建立过程,并用图形模拟的方法给出各个模型所刻画的土壤侵蚀速率与土壤剖面中^137Cs相对损失率的关系。分析表明,尽管各个模型在建立的假设和方法上以及对^137Cs沉降过程的处理上存在一定程度的差异,但是各个模型所刻画的土壤侵蚀速率与土壤剖面中^137Cs相对损失率的关系实质上都是幂函数的形式,而且这4条曲线的走势基本一致,各自计算的土壤侵蚀速率差异也较小。因此,在利用^137Cs技术示踪农耕地土壤侵蚀速率时,这4个模型都可以应用。     

野外多道伽马能谱测量在核环境地质评价中的应用

介绍了最新研制的CD-10野外便携式伽马全谱仪工作原理和主要技术指标。该仪器对伽马射线能量分析范围是30～3000keV,分析道数为1024道,对¹³⁷Cs的能量分辨率小于12%,取消了放射性稳谱参考源,采用数字稳谱技术,实现了无干扰天然伽马射线全谱(30～3000keV)测量,并以在核环境地质评价中的应用实例,说明了伽马全谱仪的主要特点和应用前景。