Ablation Characteristic of Ilmenite using UV Nanosecond and Femtosecond Lasers: Implications for Non‐Matrix‐Matched Quantification          下载免费PDF全文

Zhen Li  Zhaochu Hu  Detlef Günther  Keqing Zong  Yongsheng Liu  Tao Luo  Wen Zhang  Shan Gao  Shenghong Hu 《Geostandards and Geoanalytical Research》2016,40(4):477-491

Ilmenite (FeTiO₃) is a common accessory mineral and has been used as a powerful petrogenetic indicator in many geological settings. Elemental fractionation and matrix effects in ilmenite (CRN63E‐K) and silicate glass (NIST SRM 610) were investigated using 193 nm ArF excimer nanosecond (ns) laser and 257 nm femtosecond (fs) laser ablation systems coupled to an inductively coupled plasma‐mass spectrometer. The concentration‐normalised ⁵⁷Fe and ⁴⁹Ti responses in ilmenite were higher than those in NIST SRM 610 by a factor of 1.8 using fs‐LA. Compared with the 193 nm excimer laser, smaller elemental fractionation was observed using the 257 nm fs laser. When using 193 nm excimer laser ablation, the selected range of the laser energy density had a significant effect on the elemental fractionation in ilmenite. Scanning electron microscopy images of ablation craters and the morphologies of the deposited aerosol materials showed more melting effects and an enlarged particle deposition area around the ablation site of the ns‐LA‐generated crater when compared with those using fs‐LA. The ejected material around the ns crater predominantly consisted of large droplets of resolidified molten material; however, the ejected material around the fs crater consisted of agglomerates of fine particles with ‘rough' shapes. These observations are a result of the different ablation mechanisms for ns‐ and fs‐LAs. Non‐matrix‐matched calibration was applied for the analysis of ilmenite samples using NIST SRM 610 as a reference material for both 193 nm excimer LA‐ICP‐MS and fs‐LA‐ICP‐MS. Similar analytical results for most elements in ilmenite samples were obtained using both 193 nm excimer LA‐ICP‐MS at a high laser energy density of 12.7 J cm^?2 and fs‐LA‐ICP‐MS.  相似文献   

阿尔泰东部新生代火山岩的地球化学特点及构造环境   总被引：3，自引：0，他引：3  

王登红  李天德 《大地构造与成矿学》2001,25(3):282-289

新疆三大山系均有新生代火山岩,其中南部西昆仑、阿尔金山及天山托云等地的新生代火山岩比较发育,在新疆东北部地区的阿尔泰哈拉乔拉一带也发育新生代的陆内喷发火山岩。这套火山岩虽然面积不是很大,但具有大陆溢流玄武岩的特点。在地球化学上也具有典型热点成因洋岛玄武岩或其它地幔柱成因玄武岩的特点,如TiO2含量高大于2%、轻稀土元素和不相容元素显著富集等。表明新疆北部特别是阿尔泰造山带东部演化到新生代以后,有向裂陷拉张方向演化的趋势,标志着一个新的大地构造演化阶段的到来。  相似文献   

藏南岗巴—定日地区始新世化石碳酸盐岩微相与沉积环境   总被引：8，自引：0，他引：8       下载免费PDF全文

李国彪万晓樵  其和日格梁定益  刘文灿 《中国地质》2002,29(4):401-406

藏南岗巴-定日地区发育着西藏最晚期的海相沉积，对这套海相沉积的研究，可提供关于西藏特提斯演化晚期的良好信息，本文对岗巴-定日地区始新世遮普惹组的化石碳酸盐岩微相进行了较为详细的分析和研究。参考Wilson(1975)的标准微相，初步识别出10种微相和5种生物相类型。同时对遮普惹组中的砾状灰岩的成因机制作了有益的探讨，它完全是由沉积作用而成；胶结物不是源于物质的重新分配，而是台地边缘斜坡的等深流沉积。以此为基础，对西藏特提斯晚期沉积环境的演变进行了较为详细的分析。笔者认为：岗巴-定日盆地在始新世Ypresian-Lutetian早期接受海侵；自Lutetian晚期开始，区内总体处于一种海退环境，但由于受板块碰撞作用的影响，岗巴地区在Lutetian晚期-Bartonian晚期成为-深水坳陷盆地；至Priabonian早期，海水完全退出本区。  相似文献   

我国期气候预测的业务技术发展     

赵振国 《山东气象》2001,21(3):4-7

概述了我国短期气候预测技术和业务现代化发展的历史，分析了“九五”以来我国短期气候预测技术的新进展，探讨了未来短期气候预测技术发展的几个主要问题。  相似文献   

柴达木盆地深部物理参数的反演   总被引：1，自引：0，他引：1       下载免费PDF全文

丁中一  沈云清 《地球物理学报》1992,35(5):613-620

通过研究地球对表面载荷的响应来反演确定地球深部的物理参数.采用分为4层的地球模型,各层的介质被看作Maxwell粘弹性体.将柴达木盆地沉降发育过程中积累的沉积物作为随时间变化的载荷加于地表,通过拟合柴达木盆地沉降中心附近地区的沉降过程来研究该地区地壳的厚度及剪切模量、岩石层地幔的粘性及软流层的粘性等物理参数.计算结果表明,该地区地壳的剪切模量不会超过全球平均值的60％,岩石层地幔的粘性系数不大于1.5×10²³Pa·s.通过研究对该地区的深部物理参数得出了新的认识.  相似文献   

论直流激发极化法的视电阻率参数          下载免费PDF全文

赵聚林  涂明  冯军  王忠  吕旭红 《甘肃地质》2007,16(4):85-87

直流激发极化法，计算视电阻率的一次场采集于供电方波的末端时间，从而包含了被激发形成的二次场。在高极化率地质体上，得到的视电阻率将削弱其低阻特性或放大高阻特性。为此，建议在野外工作中，应对所采集的一次场作适当的处理后，再计算视电阻率，以降低这种影响。  相似文献   

多维标度法在矿产预测中的应用   总被引：1，自引：0，他引：1  

杨永强 《世界地质》1998,(1)

在矿产预测中常涉及一些定性变量,对这些变量的分析和应用,必须将定性描述的地质特征转化为用数值表示的变量,这就需要处理此问题的方法——多维标度法。笔者介绍了计量性的Ｔｏｒｇｅｒｓｏｎ法、准计量性的林知已夫数量化理论和非计量性多维标度法,并列举了其在矿产预测中的应用实例。  相似文献   

Water balance change for a re-vegetated xerophyte shrub area/Changement du bilan hydrique d’une zone replantée d’arbustes xérophiles     

《水文科学杂志》2013,58(2)

Abstract

Abstract Water balances for a re-vegetated xerophyte shrub (Caragana korshinskii) area were compared to that of a bare surface area by using auto-weighing type lysimeters during the 1990–1995 growing seasons at the southeast Tengger Desert, Shapotou, China. The six-year experiment displayed how major daily water balance components might vary for a bare and a re-vegetated sand dune area. Evapotranspiration from the C. korshinskii lysimeter represented a major part of the water balance. The average annual ET/P ratios varied between 69 and 142%. No seepage was observed for the vegetated lysimeter. For the bare lysimeter, on the other hand, 48 mm or 27% of observed rainfall per year occurred as seepage. These results suggest that re-vegetating large sandy areas with xerophytic shrubs could reduce soil water storage by transpiration. Also, the experimental results indicate that re-vegetating large sandy areas could significantly change groundwater recharge conditions. However, from a viewpoint of desert ecosystem reconstruction, it appears that natural rainfall can sustain xerophytic shrubs such as C. korshinskii which would reduce erosion loss of sand. However, re-vegetation has to be balanced with recharge/groundwater needs of local populations.  相似文献   

Asteroseismic study of the red giant ε Ophiuchi     

Shao-Lan Bi  Ling-Huai Li  Yan-Ke Tang  Ning Gai 《天体物理学报》2010,(12):1265-1274

  相似文献   

Analysis of High Density Regional Geochemical Soil Samples at the Council for Geoscience (South Africa): The Importance of Quality Control Measures     

Hilde Maritz  H. C. C. Cloete  Jacobus H. Elsenbroek 《Geostandards and Geoanalytical Research》2010,34(3):265-273

The Council for Geoscience (CGS, South Africa) has a statutory mandate to carry out regional geochemical mapping in South Africa that needs to be rapidly and accurately analysed. Both simultaneous X-ray fluorescence spectrometry (S-XRF) and a newly developed method using inductively coupled plasma-mass spectrometry (ICP-MS) were employed. Various trace elements that could not previously be analysed by S-XRF can now be analysed by ICP-MS for the regional geochemical mapping programme, e.g., Cd, Mo, Te and Li. Using both techniques, the CGS aims to report element distributions for some fifty elements. To ensure that element concentration levels correlate over map boundaries, quality control measures in the sampling, sample preparation and analyses were of critical importance. This paper aims to discuss the sample preparation and quality control measures as applied to the ∼5500 samples of the Giyani and Tzaneen 1:100000 scale map sheets sampled at a density of one soil sample per km². ICP-MS batch- and instrumental drift-correction procedures will be discussed. As a final step, geochemical data were overlain over simplified geological maps using geographical information system software. These maps complement existing geological information of South Africa, help in the identification of exploration targets, test exploration models and initiate further geological research.  相似文献