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921.
我国锂钾主要矿产资源大多分布在西部偏远地区,其勘查找矿或综合利用迫切需要现场快速分析技术的支持。本文介绍了自行开发的便携式Li-K分析仪的主要性能及其在锂辉石中锂的分析应用。Li-K分析仪是一种基于大气压的液体阴极辉光放电光谱仪,以待测液体为放电阴极,实现了样品中Li、K等元素的原子化和激发。该仪器以光纤传导CCD光谱仪作为检测器,其波长范围为345~1015 nm,分辨率3 nm;以Li 670.78 nm和K 769.90 nm分析谱线,在仪器最佳工作条件下测定Li、K的精密度(RSD,n=14)均低于2%,检出限为0.03μg/m L,检测范围0.1~10μg/m L。研究表明,不同酸度和酸的类型对谱线强度影响较大,且存在显著的样品基体效应,标准曲线法分析锂辉石中Li的结果偏差高达267%;而标准加入法可克服基体效应的影响,获得与ICP-OES一致性较好的分析结果,为现场开展固体样品中Li的测定奠定了基础。 相似文献
922.
Zircon M127 – A Homogeneous Reference Material for SIMS U–Pb Geochronology Combined with Hafnium,Oxygen and,Potentially, Lithium Isotope Analysis 下载免费PDF全文
Lutz Nasdala Fernando Corfu John W. Valley Michael J. Spicuzza Fu‐Yuan Wu Qiu‐Li Li Yue‐Heng Yang Chris Fisher Carsten Münker Allen K. Kennedy Peter W. Reiners Andreas Kronz Michael Wiedenbeck Richard Wirth Chutimun Chanmuang Manuela Zeug Tamás Váczi Nicholas Norberg Tobias Häger Alfred Kröner Wolfgang Hofmeister 《Geostandards and Geoanalytical Research》2016,40(4):457-475
In this article, we document a detailed analytical characterisation of zircon M127, a homogeneous 12.7 carat gemstone from Ratnapura, Sri Lanka. Zircon M127 has TIMS‐determined mean U–Pb radiogenic isotopic ratios of 0.084743 ± 0.000027 for 206Pb/238U and 0.67676 ± 0.00023 for 207Pb/235U (weighted means, 2s uncertainties). Its 206Pb/238U age of 524.36 ± 0.16 Ma (95% confidence uncertainty) is concordant within the uncertainties of decay constants. The δ18O value (determined by laser fluorination) is 8.26 ± 0.06‰ VSMOW (2s), and the mean 176Hf/177Hf ratio (determined by solution ICP‐MS) is 0.282396 ± 0.000004 (2s). The SIMS‐determined δ7Li value is ?0.6 ± 0.9‰ (2s), with a mean mass fraction of 1.0 ± 0.1 μg g?1 Li (2s). Zircon M127 contains ~ 923 μg g?1 U. The moderate degree of radiation damage corresponds well with the time‐integrated self‐irradiation dose of 1.82 × 1018 alpha events per gram. This observation, and the (U–Th)/He age of 426 ± 7 Ma (2s), which is typical of unheated Sri Lankan zircon, enable us to exclude any thermal treatment. Zircon M127 is proposed as a reference material for the determination of zircon U–Pb ages by means of SIMS in combination with hafnium and stable isotope (oxygen and potentially also lithium) determination. 相似文献
923.
JiuMei Li LiangJie Tang Yong Yue Meng Li ShengLong Zhang Yu Long ShaoHui Luo 《Arabian Journal of Geosciences》2016,9(14):630
A three-dimensional (3D) structural modeling of the Lower Cambrian–Upper Permian Yubei 3D area was performed to understand its structural evolution. This model reproduces the present-day structure of the basin and comprises 11 horizons within Lower Cambrian to Upper Permian rocks. The analysis is based on 3D depth views and faults. The results image salt movements due to tectonics and/or burial. From these observations, this paper deduces that salt structures are correlated to the main faults and tectonic events. From the model analysis, we interpret the timing and geometry of Tarim Basin tectonics. The fault geometry can be resolved based on the strike of the fault, the morphology of hanging wall strata, and the stratigraphic distribution. Emphasis is placed on gypsum rock detachment, considering its movements during the Middle Caledonian event and decoupling effects during tectonic evolution. Moreover, we point to the structural control of the Paleozoic basement and the crustal architecture (Yubei 3D Zone) on the geometry of the Tarim Basin. 相似文献
924.
安徽姑山矿浆型铁矿床Fe同位素初步研究 总被引:2,自引:0,他引:2
文章报道了宁芜矿集区内姑山矿浆型铁矿床中的铁氧化物、辉石闪长玢岩和赋矿围岩的Fe同位素组成,其δ57Fe的总体分布范围为-0.05‰~0.79‰。结果显示,姑山铁矿床的铁氧化物赤铁矿和镜铁矿均比硅酸盐岩浆结晶产物(辉石闪长岩)富集重的Fe同位素,并且硅酸盐岩浆的Fe同位素组成比已报道的火山岩的平均Fe同位素组成更富集轻的Fe同位素,表明在岩浆不混溶的过程中Fe同位素发生了分馏,富铁熔体相对富集重的Fe同位素,而硅酸盐熔体相对富集轻的Fe同位素;相对于赋矿地层(黄马青组石英砂岩)和辉石闪长玢岩,赤铁矿和镜铁矿更富集重的Fe同位素,围岩地层和闪长岩岩体则富集轻的Fe同位素。因此,姑山铁矿床的铁质不大可能来自于地层或闪长玢岩岩体,而主要来源于深部岩浆房。 相似文献
925.
Evaluation of rainfall erosivity and its temporal variation in the Yanhe River catchment of the Chinese Loess Plateau 总被引:2,自引:0,他引:2
The potential of rain to generate soil erosion is known as the rainfall erosivity (R), and its estimation is fundamental for a better understanding of the erosive ability of certain rainfall events. In this paper, we investigated the temporal variations of rainfall erosivity using common daily rainfall data from four meteorological stations during 1956 to 1989 and 2008 to 2010 periods in the Yanhe River catchment of the Chinese Loess Plateau. The adaptability of several simplified calculation models for R was evaluated and compared with the results of previous studies. An exponential model based on the modified Fournier index (MFI) was considered as the optimum for our study area. By considering the monthly distribution and coefficient of variation of annual precipitation, equations based on two indices, the MFI and its modification F F , produced a higher calculation accuracy than mean annual precipitation. The rainfall erosivity in the Yanhe River catchment has a remarkable interannual difference, with a seasonality index ranging from 0.69 to 1.05 and a precipitation concentration index from 14.51 to 27.46. In addition to the annual rainfall amounts, the extreme wave of monthly rainfall distribution also has an effect on the magnitude and temporal variation of rainfall erosivity, especially interannual variation. For long time series of rainfall erosivity, a trend coefficient r of ?0.07 indicated a slight decline in erosivity in the Yanhe River catchment from 1956 to 2010. 相似文献
926.
927.
928.
Jin Li Suo‐han Tang Xiang‐kun Zhu Zhi‐hong Li Shi‐Zhen Li Bin Yan Yue Wang Jian Sun Yao Shi Aiguo Dong Nick S. Belshaw Xingchao Zhang Sheng‐ao Liu Ji‐hua Liu Deli Wang Shao‐yong Jiang KeJun Hou Anthony S. Cohen 《Geostandards and Geoanalytical Research》2019,43(1):163-175
Iron, Cu and Zn stable isotope systems are applied in constraining a variety of geochemical and environmental processes. Secondary reference materials have been developed by the Institute of Geology, Chinese Academy of Geological Sciences (CAGS), in collaboration with other participating laboratories, comprising three solutions (CAGS‐Fe, CAGS‐Cu and CAGS‐Zn) and one basalt (CAGS‐Basalt). These materials exhibit sufficient homogeneity and stability for application in Fe, Cu and Zn isotopic ratio determinations. Reference values were determined by inter‐laboratory analytical comparisons involving up to eight participating laboratories employing MC‐ICP‐MS techniques, based on the unweighted means of submitted results. Isotopic compositions are reported in per mil notation, based on reference materials IRMM‐014 for Fe, NIST SRM 976 for Cu and IRMM‐3702 for Zn. Respective reference values of CAGS‐Fe, CAGS‐Cu and CAGS‐Zn solutions are as follows: δ56Fe = 0.83 ± 0.07 and δ57Fe = 1.20 ± 0.13, δ65Cu = 0.57 ± 0.06, and δ66Zn = ?0.79 ± 0.12 and δ68Zn = ?1.65 ± 0.24, respectively. Those of CAGS‐Basalt are δ56Fe = 0.15 ± 0.07, δ57Fe = 0.22 ± 0.10, δ65Cu = 0.12 ± 0.08, δ66Zn = 0.17 ± 0.13, and δ68Zn = 0.34 ± 0.26 (2s). 相似文献
929.
Yue‐Heng Yang Fu‐Yuan Wu Qiu‐Li Li Yamirka Rojas‐Agramonte Jin‐Hui Yang Yang Li Qian Ma Lie‐Wen Xie Chao Huang Hong‐Rui Fan Zi‐Fu Zhao Cheng Xu 《Geostandards and Geoanalytical Research》2019,43(4):543-565
Bastnäsite is the end member of a large group of carbonate–fluoride minerals with the common formula (REE) CO3F·CaCO3. This group is generally widespread and, despite never occurring in large quantities, represents the major economic light rare earth element (LREE) mineral in deposits related to carbonatite and alkaline intrusions. Since bastnäsite is easily altered and commonly contains inclusions of earlier‐crystallised minerals, in situ analysis is considered the most suitable method to measure its U‐Th‐Pb and Sr‐Nd isotopic compositions. Electron probe microanalysis and laser ablation (multi‐collector) inductively coupled plasma‐mass spectrometry of forty‐six bastnäsite samples from LREE deposits in China, Pakistan, Sweden, Mongolia, USA, Malawi and Madagascar indicate that this mineral typically has high Th and LREE and moderate U and Sr contents. Analysis of an in‐house bastnäsite reference material (K‐9) demonstrated that precise and accurate U‐Th‐Pb ages could be obtained after common Pb correction. Moreover, the Th‐Pb age with its high precision is preferable to the U‐Pb age because most bastnäsites have relatively high Th rather than U contents. These results will have significant implications for understanding the genesis of endogenous ore deposits and formation processes related to metallogenic geochronology research. 相似文献
930.
额尔宾山花岗岩岩体位于南天山晚古生代侵入岩带,对该花岗岩进行锆石U-Pb定年获得296.1±1.8Ma的年龄,为早二叠世。岩石主量元素分析结果表明,该花岗岩的Si O2含量为66.96%~67.3%,富碱(Na2O+K2O=7.53%~7.97%),K2O/Na2O1(1.15~1.27),属高钾钙碱性系列岩石;Al2O3为15.56%~15.62%,Al2O3K2O+Na2O+Ca O,属于过铝型。岩石稀土元素配分模式呈现轻稀土元素(LREE)富集((La/Yb)N=27.03~30.62)、重稀土元素(HREE)亏损((LREE/HREE)=18.2~20.1)、具有中等程度的负Eu异常(δEu=0.64~0.68)。微量元素判别结果显示,其具有I-A型花岗岩过渡的特征。结合区域地质背景综合分析,初步认定该岩体可能形成于南天山同碰撞向后碰撞构造体制转换时期,据此可以推测南天山洋盆闭合时限至少应该在早二叠世以前。 相似文献