Accurate Trace Element Reporting in Corundum: Development of Secondary Ion Mass Spectrometry Relative Sensitivity Factors

The attractive physical and chemical properties of corundum lend to this material’s importance in both its natural and synthetic forms. However, much of the quantitative work performed on this material is plagued by unknown inaccuracy as non‐matrix‐matched reference materials are used. To conduct accurate quantitative analysis using SIMS, matrix‐specific relative sensitivity factors (RSFs) were determined for eighteen trace elements in corundum using dose‐verified ion implants. The RSF values ranged from 2.56 × 10²² to 3.29 × 10²⁴ cm^‐1 with total combined uncertainty values ranging from 7 to 10%. The RSF values, which are related to ionisation potentials, showed trends consistent with expectations for an insulating oxide. The developed values were applied to calibrate reference materials for LA‐ICP‐MS and to study other natural and synthetic corundum samples. A measurement reference material calibrated for Mg, Si, Ti, V, Fe and Ga produced consistent results over ten sessions in 4 years with relative standard deviations per trace element of 5% or less, confirming the repeatability of our process. A key finding was that calibrating LA‐ICP‐MS with NIST SRM 610 and 612 glasses to analyse corundum resulted in under‐reporting trace elements Be, Ti, V, Fe, Co, Ni and Ga compared with using matrix‐matched reference materials.     

新疆北部卡拉麦里斜长花岗岩的锆石U-Pb年龄及其构造意义

新疆北部卡拉麦里构造带发育与蛇绿岩伴生的斜长花岗岩,其时代、成因及与蛇绿岩的关系是目前还存在争议的问题。本文报道了该斜长花岗岩的锆石SHRIMP U-Pb年龄和地球化学组成。研究表明,斜长花岗岩的成岩年龄为373Ma,εNd(t)与亏损地幔一致,与典型蛇绿岩中的斜长花岗岩有相似的微量元素特征,与卡拉麦里蛇绿岩中辉长岩有相似的平坦型稀土元素配分模式,两者在La/Sm-La图上符合结晶分异趋势。因此,卡拉麦里斜长花岗岩属于大洋斜长花岗岩,是来源于亏损地幔的基性岩浆通过结晶分异作用的产物,其成岩年龄373Ma代表了卡拉麦里蛇绿岩的形成时代。     

地震短临跟踪与前兆异常核实

邢台地震后,经过现场调查研究,发现了一些前兆异常现象,开展了地震监测台网和群众业余骨干测报点的建设.海城和唐山地震后,提出了专群结合、土洋结合的预报方针,进一步推动了地震前兆观测的发展.后来发展到在有发生地震危险的地方进行短临跟踪,即临时布设一些台网进行前兆学科的短期观测,以期能预测忖可能会发生的地震.     

吉林省集安安绿玉矿物学特征

安绿玉产于吉林省集安地区,为胶状隐晶质蛇纹石矿物集合体,属岫玉一个新品种。安绿玉的化学成分与蛇纹石的理论化学组成接近。x射线、红外吸收光谱、电子显微镜、穆斯堡尔谱和吸收谱研究表明:安绿玉主要由利蛇纹石组成,含有一定量正纤蛇纹石。利蛇纹石为片状、正纤蛇纹石为管状、纤维状集合体。安绿玉具多种颜色,它取决于铁的含量、价态和位置,含Fe~3+呈黄色系列,而Fe~(2+)→Fe~(3+)电荷转移吸收呈蓝色系列。利蛇纹石的Fe~(2+)、Fe~(3+)在八面体M_1和M_2位置上分布是无序的。文中还论述了玉石特征及其与成分和结构的关系。     

河南桐柏老湾金矿白云母氩-氩年龄及其地质意义

河南老湾金矿是秦岭-大别造山带中代表性金矿之一,其容矿围岩是元古宙变质岩,矿体受到NWW向老湾剪切带的控制,同时附近又有燕山期花岗岩.结合前人工作,本次研究表明,老湾金矿的形成经历了一个漫长过程,其韧性剪切带的演化(138 Ma)早在花岗岩(108～102 Ma)之前就开始了.韧性剪切带既是导岩构造也是导矿构造,含金石英脉的定位最晚(91 Ma).这一漫长过程与秦岭-大别造山带在燕山期的演化过程一致.     

A comparison of the distributions of carbazoles and dibenzothiophenes in western Qaidam Basin,Northwest China

Variations in the distributions of carbazoles and dibenzothiophenes were investigated in a set of source rocks, which differ mainly in their maturity levels during immature-mature stages. A comparison of the distributions of carbazoles and dibenzothiophenes has revealed the main results as follows- ① variations in the relative amounts of C0-, C1-, C2-dibenzothiophenes show a low correlation with that of the corresponding carbazoles, with the for- mer＇s being much higher than the latter＇s; ② variations in the relative amounts of methyldibenzothiophene isomers also display a low correlation with that of the corresponding methylcarbazoles, with 4-/4- ＋1-methyldibenzothio- phene ratio ranging from 0.52 to 0.96, while the corresponding carbazole ratio of 1-/1- ＋4-methylcarbazole only being 0.71-0.05; ③ the maturity parameter for 4,6-/4,6- ＋l,4-dimethyldibenzothiohene, ranging from 0.34 to 0.75, shows a remarkable linear correlation with the corresponding ratio of 1,8-/1,8- ＋1,4-dimethylcarbazole （R2〉0.84）. The un-correlation may indicate some different geological-geochemical fates for some isomers of dibenzothiophenes and carbazoles. The high correlation may reveal a strong maturation dependence on the dimethylcarbazole distribu- tions, indicating that attention should be paid when 1,8-/1,8- ＋1,4-dimethylcarbazole is used as a petroleum migra- tion indicator.     

扇三角洲砂体特征及其与可地浸砂岩型铀矿化的关系

本文分析了扇三角洲各相砂体的基本特征与铀矿化的可能关系,以两个实例探讨了准噶尔盆地东部大庆沟侏罗系扇三角洲垂向地层序列牲和伊犁盆地南部侏罗系水溪沟群扇三角洲垂向序列和平面岩相分布特征,指出了扇三角洲平原辫状河道砂本、水下分流河道砂体及一些前缘砂体可能是赋武存可地浸砂岩铀矿的有利围岩。     

拉曼光谱方法测量流体包裹体的内压及其应用

通过金刚石压腔和显微激光拉曼光谱方法,获得了流体包裹体中H2O-NaCl体系的O—H、碳酸根的C—O、硫酸根的S—O和正庚烷-环己烷的C—H振动拉曼位移与温度和压力关系的表达式。该研究结果可以用于实测流体包裹体在不同温度下的内压,并可由此获得流体包裹体的p-t线或等容线。这不仅有助于精确获得流体包裹体的形成温度和形成压力,也可为研究和确定流体包裹体中流体的组成和性质提供依据。     

大气中非线性Kelvin波的一个特殊形态

通过对非线性方程组的求解和讨论，指出：非线性Ｋｅｌｖｉｎ波与线性波相比，在扰动的水平结构和时间演变上都存在着显著的差异；在波动的传播方式上也较线性情形复杂。与层结大气中的正压模态有关的波动亦有与上述类似的特征。     

我国沙尘暴的危害及防御系统

20世纪60年代到90年代后期以来,沙尘暴频频急剧增加,呈现出时间早、影响广、危害大的特征。本文主要分析了沙尘暴天气的发生、发展及影响,叙述了近年来我国北方地区发生的沙尘暴典型事例,介绍了中国气象局2001年开始建设的沙尘暴监测预警工程。通过“中国沙尘暴预测预警服务系统”的运行与监测,将大大地减少和降低天气、气候极端事件的危害,达到沙尘暴天气的有效防御。