In-situ trace element analyses of zircons from Dabieshan Huangzhen eclogite: Trace element characteristics of eclogite-facies metamorphic zircon

The internal structures of zircons in eclogite from Huangzhen have been studied by cathodoluminescence(CL) microscopy. Two growth stages were distinguished:protolith magmatic cores and metamorphic overgrowthrims. These different domains were analyzed for trace ele-ments using LAM-ICP-MS. The protolith and theovergrowth zircons have different trace elements charac-teristics. The trace element contents of protolith zircons arehigh and very variable. The overgrowth zircons show a typi-cal trace element feature of equilibrium with garnet, e.g. lowcontents of HREE (132.2-197.6 ?g/g) and small differentialdegree of HREE ((Yb/Gd)CN=8.6-11.9). The contents of Nb,Ta and the ratio of Nb/Ta are lower in the metamorphic do-mains (0.5-1.4 ?g/g, 0.7-1.5 ?g/g, 0.3-1.3, respectively)than in the protolith domains (3.8-19.7 ?g/g, 2.7-12.1 ?g/g,1.0-4.6, respectively). This is the first time to give the evi-dence that the metamorphic zircon equilibrates with therutile, which formed during the peak metamorphic stage.The REEs and other trace elements data demonstrate that the metamorphic zircons overgrow in the eclogite-facies con-ditions. The trace element composition of zircon can there-fore give new ways to constrain their formation conditions.     

苏北超高压变质带榴辉岩型金红石矿床及其成因

在苏鲁超高压变质带南部数千个榴辉岩体中，已发现了40个含金红石榴辉岩体，金红石储量达数百万吨。在综述、分析该带榴耀岩的空间分布、岩石矿物学、含矿性等特性的基础上，确定了块状榴辉型和片麻状榴辉岩型两种主要矿石类型。金红石在矿石中主要呈包裹体、粒间充填、蚀变残余和热液充填四种赋存形式，分别代表了四个不同的形成阶段。电子探针分析显示，在高压、超高压变质作用期间，富含Na的深部流体对金红石的成矿可能起了重要的作用。该矿床属典型的榴耀岩型金红石矿床，在成因上与超高压变质作用有关，类似于挪威的Engebφfjellet、俄罗斯的Shubino村和意大利的Pian Paludo矿床，而不同于我国已知的主要金红石矿床。     

Rutile U-Pb age for the ultra-high pressure eclogite from the dabie Mountains,central China:Evideence for rapid cooling

The U-Pb isotope compositions of rutile, omphacite and garnet in the eclogite from the Jinheqiao area in the Southern Dabie ultrahigh-pressure metamorphic zone were analyzed. The consistent high precision U-Pb age (218 ±(1.2) Ma of rutile in eclogite from the Dabie Mountains was obtained by two ways of isochron and common Pb correction based on the composition of omphacite. This proves that the omphacite in eclogite has a U/Pb ratio (μ = 2.8) low enough to be used for common Pb correction in the analyses of rutile. Under the rapid cooling condition (40℃/Ma) the closure temperature for U-Pb diffusion in rutile is about 470℃. Thus, this U-Pb age of rutile proves that 218 Ma should be the cooling age of eclogite at 470℃ instead of the peak metamorphic age.     

微量元素与人体健康

微量元素与人类健康密切相关,科学界公认的必需微量元素有14种,这些微量元素在一定的浓度范围内对人体的生命运动起着积极而重要的作用,但是,超出了正常浓度范围,将会影响机体健康,甚至危及生命．本文从机体内微量元素和必需微量元素的含义谈起,通过对几种重要的必需微量元素的介绍以及对微量元素与世界难题癌症之间的关系的探讨,让大家对微量元素与人类健康的密切关系有所认识．     

In situ simultaneous determination of trace elements,U-Pb and Lu-Hf isotopes in zircon and baddeleyite

This paper describes a combined method of simultaneously measuring U-Pb and Lu-Hf isotopes as well as trace elements in Phalaborwa baddeleyite and 91500, GJ-1, TEMORA-1 and SK10-2 zircons by means of Neptune MC-ICPMS and Agilent Q-ICPMS connected to a 193 nm excimer laser ablation system. Material ablated by laser was carried in different proportions into Q-ICPMS for U-Pb isotopic and trace elemental and MC-ICPMS for Lu-Hf isotopic compositions. Experiments indicate that different proportions of ablated material for the Q-ICPMS and MC-ICPMS (6:4, 5:5 and 4:6 respectively) do not show any bias for the zircon/baddeleyite U-Pb age, Lu-Hf isotope and trace elemental compositions within ana-lytical errors. Using 40―60 μm spot size, the obtained U-Pb ages of Phalaborwa baddeleyite, 91500, GJ-1, TEMORA and SK10-2 zircons are 2065±15 (2σ, n=20), 1063±6 (2σ, n=19), 613±6 (2σ, n=20), 416±5 (2σ, n=20) and 32.6±0.5 (2σ, n=20) Ma, respectively. The 176Hf/177Hf ratios are 0.281231±24 (2SD, n=20), 0.282310±35 (2SD, n=19), 0.282028±34 (2SD, n=20), 0.282687±34 (2SD, n=20) and 0.282752±53 (2SD, n=20), respectively. The obtained trace elemental compositions are identical to the reference values. Therefore, this kind of technique makes it possible to simultaneously obtain the U-Pb age, Lu-Hf iso-topes and trace elemental compositions of zircon and baddeleyite, which could be an important tool in solving problems in earth sciences.     

副矿物地球化学研究进展

副矿物广泛分布于各类火成岩、变质岩和沉积岩中,对寄主岩石的形成环境有很高的敏感度。以锆石、金红石和磷灰石为例,分别从结构特征、微量元素地球化学特征和同位素年代学等方面介绍副矿物地球化学的主要研究进展。锆石中U和Th的含量、Th/U值、Zr/Hf值等均与锆石成因类型有关,但共生矿物的存在和蜕晶化等因素可能会对这些微量元素产生影响,也可能导致不准确的同位素年龄结果。金红石以高Nb和Ta为特征,不同类型岩浆岩中Nb/Ta值差异较大,Cr-Nb二元判别图解也可以用来判断变质原岩类型。Mn2+、Eu2+、Sm3+、Dy3+、Er3+等微量元素会使磷灰石在受到阴极射线的激发下产生黄、绿或蓝色的光,因此磷灰石的发光特征可以反映其化学组成。不同类型岩石中的副矿物REEs的组成特征明显不同,说明受后期地质活动影响较弱的副矿物仍能精确指示其形成环境。由于锆石中的Ti和金红石中的Zr均是温度的函数,因此是重要的地质温度计,而榍石中的Zr对压力较敏感,常被用作地质压力计。锆石、金红石和磷灰石均为高铀矿物,均可进行U-Pb同位素定年,副矿物Sm-Nd、Lu-Hf也已逐渐成为常规定年法。热年代学得到快速发展以来,高-中-低温同位素体系与地质温度计和压力计的配套使用,不仅能够获取更准确的年龄值,还能提供更完整的地质体演化p-T-t曲线。副矿物地球化学将会更注重于尚未深入研究的其他副矿物在岩浆和高温变质过程中、在油气成藏演化的不同阶段中、在微生物活动影响下的内部结构和成分变化,新的同位素体系、纳米技术和精度更高的分析仪器等的发展会为副矿物研究带来更多突破。     

锆石U-Pb定年与微量元素分析的地质应用

 锆石U-Pb定年与微量元素同时测定的原位微区分析是目前应用最广泛的地质测年方法之一,对锆石形貌学、内部结构及地球化学特征进行深入研究,是正确理解、解释锆石原位微区分析测年结果的关键。通过锆石的阴极发光图像（CL）、背散射电子图像（BSE）,结合锆石的Th/U比值及稀土配分模式曲线特征,可判别不同锆石的成因类型;通过锆石的微量元素分析,可判别锆石寄主岩石的成因类型及形成环境;利用Ti温度计可限定岩体的岩浆源区深度范围,结合锆石寄主岩石类型及寄主岩石中深源包裹体的研究,可进一步推断锆石母岩浆的起源。锆石U-Pb定年与微量元素分析相结合的地质测年方法,已成功地应用于最大沉积地层时代限定、碎屑岩物源分析以及古洋盆演化过程约束等方面,且具有强有力的发展前景。     

人发中微量元素的测定及试样消化方法的比较

本文用原子吸收分光光度法和ICP发射光谱法测定了贵阳,安顺等地儿童发样中的微量元素,着重进行了发样消化方法的比较,实验证明HNo_3-H_2O_2混合液消化法快速、简便、准确。     

西北地区4种麻虻超微结构及其微量元素的初步观察

首次用于电子扫描显微镜对甘肃，宁夏和内蒙地区的甘肃麻虻Ｈ．ｋａｎｓｕｅｎｓｉｓ，等额麻虻Ｈ，ｈｅｄｉｎｉ，土麻虻Ｈ。ｔｕｒｋｅｓｔａｎｉｃａ，低额麻虻Ｈ．ｕｓｔｕｌａｔａ的触角，尾器外部开矿作了初步观察，并对尾器亚生殖板所含向量元素作了测析。     

Trace elemental records of short-lived heating during exhumation of the CCSD eclogites

Trace element compositions of garnet, omphacite and apatite in ultrahigh-pressure eclogites from the main hole of the Chinese Continental Scientific Drilling (CCSD) project were in situ analyzed by the LA-ICP-MS method. Although both garnet and omphacite have homogeneous major element composi-tions, their trace elements show zonations from core to rim in rare earth elements. In particular, middle rare earth elements in the garnet, heavy rare earth elements in the apatite and all rare earth elements in the omphacite increase from core to rim, respectively. Based on dependence of partition coefficients on temperature and pressure in these minerals, we suggest that the trace elemental zonations in these minerals may record a short-lived heating event during exhumation.     

高血压病人血清及红细胞中7种元素的测定比较及其临床意义

近年来,微量元素代谢与心血管疾病的密切关系越来越多的引起人们的关注,许多动物实验表明微量元素与高血压有关,还有报道指出,摄入微量元素缺乏也可导致高血压。因此,研究高血压病人体内微量元素变化规律更为人们所重视。目前,有关高血压与血清微量元素变化之间关系的研究报道不少,但意见尚不一致,为此,我们在测定高血压病人血清中锌、铜、铁、钙、硒、镉含量的同时,做红细胞内液相应含量的测定比较,以深入探计这些元素的代谢变化规律,为高血压病人的病因及防治研究提供科学依据。     

奶牛体中的锌及镉

用等离子体发射光谱测定了奶牛肝、肾等锌及镉的含量。初步掌握了含量大小顺序及含量与健康状况等的关系。     

ICP-AES测定野玄参中微量元素

提出用电感偶合等离子体原子发射光谱（ICP-AES）测定野玄参经干法、湿法处理中的微量元素。选用合适的分析线和ICP光谱的工作参数。对数据进行了统计处理和综合评估。相对标准偏差小于4％，回收率为90．0-99．4％。     

灰渣的湿法消化法及其利用

采用高压消化罐法消化样品，采用正交试验设计实验方案，用ICP-AES测定了煤燃烧后底灰中的镁、锰、镍、钾、钙、铝、铁、铜、镓、钛、汞、钒、锗、铈14种元素的含量，方法回收率在89.0％～108．7％之间，相对标准偏差均小于1．97％．方法简单、快速、准确性好，实现了多元素同时测定，测量结果表明，煤燃烧后的底灰与原煤相比微量金属元素普遍得到了富集．     

中成药六味地黄丸中微量元素的分析

采用湿法、干法来处理六味地黄丸,用ICP-AES法同时测定As、Pb、Se、Mn、Sr、Zn六种微量元素.通过比较,硝酸作灰化助剂并用王水溶解残渣的干法效果最佳.在最佳仪器工作条件下,测定的各微量元素的检出限在0～0 534μg/mL之间;各种微量元素回收率在95 13～101 7%之间,相对标准偏差小于2 00%,符合微量元素分析要求.