Natural Evaporation of Dangxiongcuo Salt Lake Spring Brine in Tibet,China

正1 Introduction Dangxiongcuo salt lake(Figure 1),which is located in the southwest of Tibet,China,is rich in valuable mineral elements like lithium,potassium,boron,rubidium,caesium     

Lithium distribution and isotopic fractionation during chemical weathering and soil formation in a loess profile

Lithium (Li) is a fluid-mobile element and δ⁷Li in secondary deposits represents an excellent proxy for silicate weathering and authigenic mineral formation. The soil samples from 1205 to 1295 cm in the Weinan profile, one of the best developed loess-paleosol sequences covering the last glacial–interglacial climatic cycle, were collected and chemically separated into detritus and carbonate fractions for subsequent analyses of Li, δ⁷Li, major and trace elements. Other desert specimens (i.e., Qaidam Desert, Tengger Desert, Badain Juran Desert and Taklimakan Desert) near the Chinese Loess Plateau (CLP) and various standard clays were analyzed for assisting provenance determination. The Li and δ⁷Li distributions in the detritus are rather homogeneous, 1.4–2.0 μg/g and +2.5‰ to +4.7‰, respectively, compared with the carbonate fraction. The detrital δ⁷Li varies systematically with magnetic susceptibility and grain size changes, reflecting significant Li isotopic variation associated with sources and mineralogy of detrital material. On the other hand, Li and δ⁷Li in carbonates show large changes, 781–963 ng/g and −4.1‰ to +10.2‰, respectively. These carbonate δ⁷Li correlated well with the estimated index of chemical weathering, as a result of Li mobilization and soil formation during chemical weathering.     

天津蓟县地区金、钨、钼矿自然重砂与地球化学区域找矿方法效果

结合蓟县地区矿产分布特征,应用1∶20万自然重砂和1∶5万水系沉积物地球化学找矿方法,在蓟县地区金矿、钨矿、钼矿中进行区域找矿方法效果研究。研究其异常分布特征,发掘出了新的找矿信息。研究发现,所圈出的自然重砂和地球化学异常能直接指示相应地质体的含矿性,特定矿物组合的自然重砂异常和区域地球化学异常在某些区域分布上比较吻合,二者均具有找矿指示作用。     

马达加斯加南部Tranomaro地区矽卡岩型钍矿钍的赋存状态及钍矿物特征研究

Tranomaro地区钍矿化主要赋存在矽卡岩化Tranomaro辉岩中,其主要矿物成分有透辉石、方柱石和碳酸盐。钍以独立的钍矿物形式存在于辉岩中的辉石、方柱石、橄榄石及碳酸盐等矿物中,钍矿物大小为0.2～0.5mm,无共、伴生金属矿物。经电子探针测定,钍矿物的主要成分为ThO2、UO2和PbO,根据其成分特征和镜下特征确定钍矿物主要为方钍石和铀方钍石。赋矿主岩中无明显热液活动迹象,钍矿物主要形成于早（干）矽卡岩阶段。     

花岗岩地区水-岩反应次生矿物的沉淀饱和指数估算

水-岩反应次生矿物的沉淀作用不仅控制着地下水成分的演化,而且对核素的迁移和阻滞作用有重要影响。但在常温系统中,矿物的成核生长需要过饱和驱动力的存在,而且不同次生矿物成核生长所需的过饱和度有差异。本文在对日本和加拿大花岗岩地区水-岩系统的地质和地球化学特征进行分析研究的基础上,使用地球化学模拟软件PHREEQC2．15和数据库Ilnl．dat计算了次生矿物在地下水中的饱和指数,从而对各种矿物的沉淀饱和指数进行了估算。结果表明,方解石的化学活动性较强,容易溶解和沉淀,其沉淀饱和指数大约为0．5;针铁矿是地下水中铁的主要沉淀形式,其饱和指数的计算结果与pe值关系密切,沉淀饱和指数高达4．0±0．5;结合高岭石、伊利石、钙蒙脱石和钠蒙脱石之间的相平衡关系,估算其沉淀饱和指数分别为4．0±0．5、4．5±0．5、4．3±0．5和4．3±0．5。     

The accumulation of radiocesium in coarse marine sediment: effects of mineralogy and organic matter

The controlling factors affecting the accumulation of (137)Cs in marine sediment have not been investigated in detail, especially in coarse grained sediment. Eighty eight coarse marine sediment samples near Wuljin, Korea, were characterized by quantitative X-ray-diffraction (XRD), gamma-ray, and total organic carbon (TOC) analysis. Those factors were then compared. The grain size was in the range of -0.48 to 3.6Mdphi corresponding to sand grains. TOC content was in the range of 0.06-1.75%, and the concentration of (137)Cs was 相似文献   

Sillimanite group minerals: a new promising raw material for the Russian aluminum industry

The raw-material base of the Russian aluminum industry is considered. The raw materials include common (bauxites, nepheline syenites) and uncommon (nepheline ores, synnyrites, anorthosites, power-and-heating plant ashes, kaolines) types of ores. With regard to many criteria (reserves and quality of ores, technology of their processing, etc.), the problem of alumina deficit can be solved by mining sillimanite group minerals Al₂SiO₅ (wt.%: Al₂O₃ = 62.9, SiO₂ = 37.1), namely, andalusite, sillimanite, and kyanite. Their proved reserves converted to the final product (aluminum) exceed 400 mln tons. This will be enough for more than a hundred years provided that aluminum is produced in the present-day output (4 mln tons in 2008). Almost all deposits can be explored by strip mining, with application of the gravitation, flotation, and electromagnetic separation methods for ore dressing. The alumina content in concentrates reaches 60–62 wt.%. Only high-grade bauxites and the above concentration methods can ensure such a high yield of Al₂O₃. Sillimanite group minerals can be processed together with nepheline ores by sintering or be used for the direct electrothermal production of silumin and aluminum, excluding the alumina production stage. The latter method is the most promising in Russia.     

重液法分离密度差值很小的单矿物的技术及其应用

介绍了密度差值很小的单矿物的分离技术方法,并利用重液折光率千分位和万分位的细微区别分离单矿物石英和绢云母。该方法由石英与长英质混合物的分离技术,推广到绢云母与绢云母长英质混合物的分离技术,改进后的重液分离技术具有快速、高效、经济的特点。当重液的折光率为1.577~1.580时,石英的分离纯度能达到95﹪~99﹪;当重液的折光率为1.5895~1.5840时,绢云母的分离纯度能达到90﹪~99﹪。     

Heavy minerals clustering analysis in application of provenance analysis of Kong 2 Member in Kongnan area

The main task of provenance analysis is to determine the source of sediments and the position of parent rocks. Provenance analysis may find out the relationship between erosion districts and sediment zone, between the uplift and the depression in the process of basin development. The authors use the method of heavy mineral clustering analysis and estimate the provenance direction of Huanghua Depression in the Paleogene Kong 2 Member. Research shows that there were five provenance areas of Kong 2 Member in Kongnan area.They are western (Shenusi), northwestern (Cangzhou), eastern (Ganhuatun), northeastern and southeastern. The main provenance areas were northwestern and western, while the southern provenance could not be ruled out. And these areas are consistent with the known provenance areas.     

豆荚状铬铁矿中微米级新矿物的发现及指示意义

向着地球深部进军是未来地质科学研究的战略目标之一,微区则是探寻深部地幔元素迁移和物质循环的关键。分子、原子级矿物的分析研究将在解密深部地幔物理化学条件、物质组成中扮演重要角色。蛇绿岩中豆荚状铬铁矿是微米级矿物的主要载体之一。近年来,随着单晶衍射仪、微区衍射和透射电镜等实验技术的发展和应用,在豆荚状铬铁矿中发现了一系列微米级矿物,为揭示地幔物质组成和演化历史提供重要信息。铬铁矿中发现新矿物的矿床包括中国西藏的罗布莎铬铁矿矿床和希腊中部Othrys矿床。其中,罗布莎铬铁矿矿床中发现包括罗布莎矿、林芝矿、那曲矿、藏布矿、雅鲁矿、曲松矿、自然钛、青松矿、巴登珠矿、志琴矿、经绥矿、康金拉矿及文吉矿在内的13种新矿物;Othrys蛇绿岩的Agios Stefanos矿床发现的新矿物有arsenotu? ekite、eliopoulosite、tsikourasite和grammatikopoulosite。这些新矿物以过渡族元素(Fe、Cr、Ni、Mo、V等)、钛的硅化物、碳化物、镍的磷化物等自然元素及金属化合物为主。它们多以矿物发现地或为地学研究做过卓越贡献的科学家名字命名。微米级矿物的发现拓展...