Determination of Rare Earth Elements and Thorium at Nanogram Levels in Ultramafic Samples by Inductively Coupled Plasma‐Mass Spectrometry Combined with Chemical Separation and Pre‐concentration     

Yali Sun  Shengling Sun  Christina Yan Wang  Peng Xu 《Geostandards and Geoanalytical Research》2013,37(1):65-76

A method was developed for the determination of low‐level rare earth elements (REEs) and thorium in ultramafic samples by inductively coupled plasma‐mass spectrometry. The conventional method for the digestion of ultramafic rocks using HNO₃ and HF results in considerable amounts of insoluble fluorides because of the high contents of Mg (generally up to 24% m/m) in these rocks. In this study, we used H₃BO₃ as a complexing agent to break down the insoluble fluorides, and then separated the REEs from Fe and Mg major and Ba, Ca, Cr minor matrices by anion exchange and co‐precipitation, respectively. The whole procedural blanks estimated from sample‐free analyses ranged from 0.232 ng for Ce to 0.006 ng for Tm and Lu. Limits of detection for this method, defined as three times the standard deviation of these blank analyses, varied from 0.51 ng g^?1 for Ce to 0.03 ng g^?1 for Lu. The recovery of REEs using this technique, as determined using the standard addition method, ranged from 92.9% for Y to 102.0% for Er with 3% (RSD) variation. The method was validated using GAS (GeoPT‐12), JP‐1 and PCC‐1, and the results were comparable to literature values, elucidating the applicability to the determination of ultra trace REEs in ultramafic rocks.  相似文献   

Methodology for Rare Earth Element Determinations of Uranium Oxides by Ion Microprobe     

Jessica Bonhoure  Philippe Kister  Michel Cuney  Etienne Deloule 《Geostandards and Geoanalytical Research》2007,31(3):209-225

A methodology for the determination of the rare earth elements in uranium oxides by ion microprobe has been set up on a Cameca ims-3f instrument. An uranium oxide reference material from a syn-metamorphic uranium deposit related to albitisation has also been developed for this type of analysis. Applications of the methodology are presented for a series of uranium oxides selected from some major uranium deposit types: from the world's highest grade unconformity-related uranium deposit from the Athabasca Basin (Saskatchewan, Canada; the Shea Creek and the McArthur River examples), a perigranitic vein-type deposit (Pen Ar Ran, Vendée, France) and a volcanic caldera-related deposit (Streltsovkoye, Transbaikalia, Russia). Each type of uranium deposit appears to have a specific REE signature. All REE patterns from the Shea Creek and the McArthur deposits are characterised by bell-shaped patterns centred on Tb-Dy and similar to those already published for uranium oxides from unconformity-related deposits from Australia. Such bell-shaped REE patterns centred on Tb-Dy may therefore be considered as a typical signature of uranium oxides from Mesoproterozoic unconformity-related deposits. A smoother bell shape pattern centred on Eu characterises the syn-metamorphic albitisation related deposit of Mistamisk selected for the reference material. The REE patterns from the Pen Ar Ran deposit show a fractionation from LREE to HREE with anomalously high abundances of Sm, Eu and Gd with respect to the other REEs, similar to the REE patterns of uranium oxides from the volcanic-related deposits of Streltsovkoye.  相似文献   

人类圈与地球系统   总被引：1，自引：0，他引：1  

陈之荣 《地球物理学进展》1995,10(2):106-110

作为最新地球圈层的人类圈和地球系统是现代地球科学中两个重要的基本概念。正确而深刻地认识这两个概念对全球环境变化和持续发展等问题的研究具有重要的意义。目前对它们及其相互关系尚缺乏统一的认识。本文主要讨论：（１）对地球系统的三种理解；（２）人类圈与人类活动、生物圈和智慧圈等的基本区别；（３）人类圈与地球系统的关系，并主张人类圈是现代地球系统中五个地球圈层之一。  相似文献   

综合物探方法在锂铍稀有、稀土矿勘查中的应用研究     

保善东  曾彪  白宗海  黄青华  苑永涛  祁文  熊寿加 《地质与资源》2022,31(1):59-67,46

对矿石中放射性核素的含量组合与岩石含矿量进行相关性分析,进而指导锂铍稀土矿资源勘查工作.采用ENVI Pro型质子磁力仪和ARD型多道伽玛能谱仪,对茶卡北山地区花岗伟晶岩脉进行磁性特征测量和放射性特征测定,确定238U、232Th、40K含量分布规律和异常位置,划分含矿岩体,提取信息并进行磁异常和放射性元素含量的相关性...  相似文献   

湛江湾海域表层沉积物稀土元素特征及其物源指示意义     

远继东  姜正龙  代友旭  郝连成  张健康  张德程  郑立龙 《现代地质》2022,36(1):77-87

通过对湛江湾近海海域表层沉积物样品粒度和稀土元素(RE E)测试分析,系统地研究海域沉积物稀土元素地球化学特征并探讨其物质来源.结果表明,研究区沉积物的稀土元素含量变化较大,平均值为163.23μg/g,湾外的REE含量(168.61μg/g)高于湾内的REE含量(142.17μg/g);不同类型沉积物的稀土元素含量存...  相似文献   

Anomalous Variation of VLF Signals in the Total Solar Eclipse of 22nd July 2009     

Xue-Feng Zhang  Ruo-Yin DuSheng-Min Gu  Tong WuYou-Ning Wang 《Chinese Astronomy and Astrophysics》2011,35(1):54

Using the sudden ionospheric disturbance (SID) monitor provided by the Stanford University, the very low frequency (VLF) signals were observed in Nanjing during the total solar eclipse on 22nd July 2009. It is found that the intensity of the VLF signal varied anomalously during the total solar eclipse, exhibiting the effect similar to the sunrise and sunset, and that the intensity of the VLF signal strongly fluctuated, exhibiting the effect similar to thunderbolts. Moreover, the signal intensity enhanced in short periods both before and after the total eclipse. Based on the discussion on the reliability of the observed data and the comparison with the previous observations, it is found that the ionosphere exhibits some variations previous to the total solar eclipse.  相似文献   

区域GPS网实测电离层变化和卫星硬件延迟的可靠性研究   总被引：1，自引：0，他引：1  

薛军琛  宋淑丽  朱文耀  卢秀山 《天文学报》2011,52(4):310-321

根据高精度卫星导航定位的实际需要,介绍了利用中国GPS区域网双频相位平滑伪距实测数据,准实时监测区域网电离层电子总含量(TEC)变化和GPS卫星硬件延迟(DCB)的方法和结果.着重研究了区域网独立测定DCB的可靠性,利用中国境内的GPS站点分别构造了3个大小不同的区域网,通过实测DCB和垂直电子总含量(VTEC)与CO...  相似文献   

An Analysis of UT1 Determined by IVS Intensive Observations     

Wang Guangli  Xu Minghui 《Chinese Astronomy and Astrophysics》2012

In this paper the history and status of the IVS (International VLBI Service for Astrometry and Geodesy) UT1 Intensive observations are briefly re- viewed, and the deficiencies and error sources in the current Intensive observa- tions are investigated. An in-depth analysis of the IVS Intensive observation data from February 1984 to August 2011 with different observation networks is carried out, and the progress of the UT1 accuracy obtained by the Intensive observations during this period is discussed. By comparing the results from dif- ferent networks, a difference of some dozens of microseconds between different networks is found. The results of the IVS Intensive observations with Sheshan Station participated in are analyzed, it shows that the Sheshan Station perfor- mance as well as other stations. Finally, from the comparison and analysis of different UT1 series, it is concluded that there is an uncertainty with a level of 10 microseconds between the UT1 values obtained from the IVS Intensive observations and the values of the IERS (International Earth Rotation Service) C04.  相似文献   

数字地球及其军事应用初探   总被引：1，自引：0，他引：1  

张晓楠  王宏伟  刘汉生  谷宇航 《北京测绘》2013,(3):16-18,9

数字地球是全球信息化以及各国军事竞争的必然产物,在现代化战争和国防建设中具有十分重大意义。本文阐述了数字地球的概念及地位作用,研究了数字地球军事应用开发环境的构建,最后重点论述了数字地球在军事上的应用及应用现状。  相似文献   

临夏台地电阻率变化与震兆现象分析   总被引：2，自引：1，他引：1  

严玲琴  郑卫平  张辉  张昱 《中国地震》2013,29(1):168-176

以甘肃省临夏台1981年以来的地电阻率资料为基础,利用数理统计和相关分析方法,分析该台地电阻率的变化特征,探讨EW和NS两测向之间数据的相关性,以及与大夏河流量变化的对应关系,认为该台两测向数据间具有很高的相关性,可能与区域地下介质具有较均匀的电性结构有关;分析了该区降水和地下静水位对地电阻率的影响,认为地下静水位的影响更显著.此外,探讨了临夏台地电阻率资料作为地震前兆的意义,认为该台资料对甘东南及甘青交界地区的中强地震反应敏感,以下降型破年变异常为主,呈现出震级越大,异常持续时间越长的特点.该台资料同时对甘青地区成组中强地震有所反应,显示出异常持续时间长、幅度大和恢复慢的特点.  相似文献