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1.
新疆阿尔泰别也萨麻斯锂铌钽矿区广泛分布着二云母二长花岗岩，是矿化伟晶岩脉群的直接围岩。该岩体是北阿尔泰至今唯一识别出的奥陶纪花岗岩体。本文对别也萨麻斯矿区二云母二长花岗岩进行了全岩主微量以及Nd同位素分析，结果表明，岩体具有以下成分特征：富硅（SiO2=72. 93%~73. 14%）和铝（Al2O3=14. 60%~14. 82%），相对富钾（K2O/Na2O=1. 17~1. 27），全碱含量中等（Na2O+K2O=7. 96%~8. 30%），铝饱和指数A/CNK值高（1. 21~1. 28），属于高钾钙碱性强过铝质花岗岩；富集轻稀土元素、亏损高场强元素（Zr、Hf、特别是Ti）、LaN/YbN值低（6. 70~9. 28），具明显的铕负异常（δEu=0. 43~0. 47）；具有负的εNd(t)值（-4. 2~-2. 9），Nd模式年龄值在1. 42~1. 52 Ga。以上特征表明别也萨麻斯二云母二长花岗岩属于高分异I型花岗岩，其原始岩浆主要来源于古老地壳的部分熔融，并混入了部分新生地壳物质组分。别也萨麻斯二云母二长花岗岩形成于初始的陆缘弧环境，与中阿尔泰、南阿尔泰识别出的奥陶纪岩体形成的构造背景一致。别也萨麻斯稀有金属成矿不是发生在奥陶纪的陆缘弧环境下，结合区域资料，奥陶纪陆缘弧环境不是新疆阿尔泰稀有金属矿化发生的有利环境。 相似文献
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东秦岭稀有金属伟晶岩的类型、内部结构、矿化及远景——兼与阿尔泰地区对比 总被引：2，自引：1，他引：1
东秦岭地区和阿尔泰造山带均产出大量稀有金属伟晶岩,是中国重要的稀有金属产地。前者工作程度低,远景尚不明朗;后者规模巨大。开展成矿条件对比研究十分必要。东秦岭地区产出铍矿、锂矿和复杂稀有金属矿,以锂矿化为主,伟晶岩类型复杂,包括绿柱石-铌铁矿型、复杂型锂辉石亚型、复杂型锂云母亚型和钠长石-锂辉石型。阿尔泰稀有金属伟晶岩发育多种稀有金属矿化组合,伟晶岩类型为绿柱石-铌铁矿型、复杂型锂辉石亚型和钠长石-锂辉石型。东秦岭稀有金属伟晶岩的内部结构分带型式包括对称分带结构、均一结构和分层结构,阿尔泰稀有金属伟晶岩以对称分带结构为主,也见均一结构。东秦岭与阿尔泰稀有金属矿石矿物相近,东秦岭产出更多含锂磷酸盐矿物。东秦岭稀有金属伟晶岩分异演化程度相对集中且高,阿尔泰稀有金属伟晶岩分异演化程度跨度大。东秦岭和阿尔泰锂矿的锂矿化主要发生于岩浆就位前,复杂稀有金属矿稀有金属富集作用发生在岩浆就位前和就位后,但阿尔泰复杂稀有金属矿经历了更为复杂和极度的分异演化过程。东秦岭稀有金属伟晶岩可能与同期花岗岩为同一熔融事件的产物,与早期花岗岩来自同一物质来源。阿尔泰稀有金属伟晶岩与花岗岩关系复杂,但大量早期花岗岩的形成提高了地壳成熟度,有利于形成晚期稀有金属伟晶岩。东秦岭稀有金属伟晶岩产出于北秦岭单元中,形成于晚造山和造山后阶段,集中于造山后阶段,稀有金属矿化呈多期断续叠加特征。阿尔泰稀有金属伟晶岩主要产出于琼库尔-阿巴宫地体和中阿尔泰山地体内,集中于造山后和非造山阶段。伟晶岩岩浆活动受控于物质来源和造山作用。储存稀有金属的岩石在造山作用中熔融,发生多期的大规模花岗质岩浆活动,稀有金属通过长期复杂的分异演化过程在残余熔体中不断富集。这种富挥发分和稀有金属的过铝质硅酸盐岩浆随后上升就位,可经后续冷却结晶和不混溶作用进一步富集稀有金属,从而形成稀有金属伟晶岩。东秦岭具有形成含稀有金属高度分异演化岩浆的有利条件,该区具有寻找铍矿和复杂稀有金属矿的潜力。 相似文献
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中亚造山带以晚古生代成矿为特色,但最近十几年来在新疆阿尔泰、东天山等发现越来越多的三叠纪矿床,包括3个超大型矿床。在古生代造山带中为什么三叠纪能够成矿和成大矿,不同类型矿产特征和分布规律是值得关注的重要科学问题。目前确定新疆中亚造山带19个三叠纪矿床主要为花岗伟晶岩型稀有金属矿床、斑岩型钼矿床和矽卡岩型钨矿床。花岗伟晶岩型稀有金属矿床分布于阿尔泰,斑岩型钼矿床、矽卡岩型钨矿床和钨(钼)矿床分布于东天山。19个矿床的成矿年龄变化于193～248 Ma,峰值为215 Ma。不同矿床类型成矿时代略有差别,形成时间相对较早的有矽卡岩型,其次是斑岩型,伟晶岩型形成时间跨度最大,多数形成于晚三叠世,少数延续到早侏罗世。东天山沙东-小白石头一带钨矿和阿尔泰稀有金属矿最具找矿潜力。 相似文献
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河南省官坡镇境内出露大量花岗伟晶岩脉,部分花岗伟晶岩脉发育稀有金属或稀有多金属矿化,具有稀有金属找矿潜力和研究价值。通过野外地质调查、岩相学观察和元素地球化学分析,对官坡花岗伟晶岩的特征和成因进行研究。结果显示: 官坡花岗伟晶岩脉具有分布集中、延伸稳定、规模较大、结构带发育完整、物质组成复杂的特点; 花岗伟晶岩主量元素具有高硅、富碱、过铝质及低铁、镁、钙和钛的特点,在成因上可能与灰池子花岗岩具有亲缘性,推测是该花岗岩高度演化后的产物。该研究进一步提高了对该区花岗伟晶岩的研究程度,为区内稀有金属矿勘查提供借鉴。 相似文献
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新疆阿尔泰以发育VMS型多金属矿、与海相火山作用有关的铁矿、伟晶岩型稀有金属矿和造山型金矿为特色,近年来新疆维吾尔自治区有色地质勘查局地质矿产勘查研究院发现了巴斯铁列克中型钨多金属矿,这是首次在阿尔泰发现的钨矿,拓展了阿尔泰找矿思路。巴斯铁列克钨多金属矿赋存于矽卡岩中,成矿过程划分为早期矽卡岩阶段、退化蚀变阶段和石英-硫化物阶段,其中退化蚀变阶段是白钨矿主要成矿阶段,石英-硫化物阶段是铜锌金的主要成矿阶段。切穿多金属矿体的伟晶岩脉锆石LA-Q-ICP-MSU-Pb加权平均年龄为275.4Ma,矿石中辉钼矿Re-Os等时线年龄为284.4 Ma,厘定巴斯铁列克钨多金属矿形成于284Ma,属早二叠世成矿。成矿时代及岩体年龄表明,巴斯铁列克钨多金属矿的形成与矿区西可斯尔鬼黑云母二长花岗质岩浆期后热液交代康布铁堡组大理岩和变粒岩形成的矽卡岩有关。 相似文献
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湖南晚侏罗世金鸡岭花岗岩体是南岭地区典型W—Sn成矿岩体之一,内部发育黑云母花岗质伟晶岩团块和文象花岗质条带状伟晶岩脉。金鸡岭花岗岩和黑云花岗伟晶岩中的黑云母具有相似的地球化学特征,均表现出高的FeO、TiO2、Al2O3含量和低的MgO、CaO、Na2O、MnO含量,以及富集成矿元素Nb、Ta、W、Sn,亏损Sr、Ce、Eu等微量元素特征,从花岗岩体到黑云花岗伟晶岩,岩浆的形成温度和氧逸度降低,云母中Al2O3、Li2O*含量升高,TiO2、MgO含量降低,黑云母由铁叶云母演变为黑鳞云母。结合前人资料,金鸡岭花岗岩与黑云花岗伟晶岩均源于元古宙地壳的深熔作用,伟晶岩为花岗岩浆在晚期分异演化的产物,形成于岩浆—热液转化阶段。伟晶岩阶段是稀有金属元素显著富集,乃至进一步成矿的重要阶段。 相似文献
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湖南晚侏罗世金鸡岭花岗岩体是南岭地区典型W—Sn成矿岩体之一,内部发育黑云母花岗质伟晶岩团块和文象花岗质条带状伟晶岩脉。金鸡岭花岗岩和黑云花岗伟晶岩中的黑云母具有相似的地球化学特征,均表现出高的FeO、TiO2、Al2O3含量和低的MgO、CaO、Na2O、MnO含量,以及富集成矿元素Nb、Ta、W、Sn,亏损Sr、Ce、Eu等微量元素特征,从花岗岩体到黑云花岗伟晶岩,岩浆的形成温度和氧逸度降低,云母中Al2O3、Li2O*含量升高,TiO2、MgO含量降低,黑云母由铁叶云母演变为黑鳞云母。结合前人资料,金鸡岭花岗岩与黑云花岗伟晶岩均源于元古宙地壳的深熔作用,伟晶岩为花岗岩浆在晚期分异演化的产物,形成于岩浆—热液转化阶段。伟晶岩阶段是稀有金属元素显著富集,乃至进一步成矿的重要阶段。 相似文献
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陕西省的稀有稀土金属找矿工作始于六十年代初,在成矿类型上仅限于花岗伟晶岩和少量碱性岩。1970年后,随着地质工作重点的转移,稀有稀土金属的普查找矿工作才暂缓下来。近年,笔者又在从事陕南稀有稀土金属矿产的有关工怍,收集了一些资料,同时根据稀有稀土金属的成矿专属性、成矿地质条件及各种矿化因素的空间分布,为开展稀有稀土金属的普查找矿工作,仅将陕南地区初步划分为以下八个成矿远景区(见图1)。现将其简介于后,以供参考,不当之处诚望批评指正。 相似文献
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土贵乌拉附近伟晶岩型白云母矿床的特点、成因及工业类型的初步划分 总被引：1，自引：0，他引：1
一、前言我国内蒙南部花岗伟晶岩分布甚广,土贵乌拉一带伟晶岩中白云母化作用颇为普遍,其中××山 I-1号伟晶岩脉中所产的巨晶板状白云母质佳量大,具有极高的工业价值。但是对这个地区白云母矿床的特点 相似文献
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奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
12.
A catastrophic rockslide-debris flow in Wulong, Chongqing, China in 2009: background, characterization, and causes 总被引：7，自引：3，他引：4
Qiang Xu Xuanmei Fan Runqiu Huang Yueping Yin Shengshan Hou Xiujun Dong Minggao Tang 《Landslides》2010,7(1):75-87
On June 5, 2009, a catastrophic rockslide-debris flow occurred at the crest of the Jiweishan Mountain in Wulong, Chongqing,
China. Approximately five million cubic meters of limestone blocks slid along a weak interlayer of bituminous and carbonaceous
shale. The source mass descended from the upper part of the slope rapidly, crossing a 200-m wide and 50-m deep creek in front
of it. Blocked by the opposite steep creek wall, the sliding mass changed its direction and traveled a further 2.2 km along
the creek in debris-flow mode, finally forming a large accumulation zone with an average depth of 30 m. This is one of the
most catastrophic rockslide events in recent years in China. It buried 12 houses and the entrance of an iron mining tunnel
where some 27 miners were working inside. Ten people died, 64 missing, and eight wounded. Immediately after this disaster
happened, the government organized an expert team to assist the rescue work. As one of the geological experts, the author
did a lot of field investigations and collected first-hand information. Multi-methods including the remote sensing, 3D laser
scanning, geophysical exploration, and numerical modeling were used for analyzing the characteristics and the triggering mechanism
of the Wulong rockslide. The preliminary investigation results reveal that this rockslide with poor geological conditions
was mainly induced by the gravitation and the karst effect and also affected by the previous mining activities. The research
in this paper is meaningful and useful for further research on such kind of rockslides that are geologically similar to the
Wulong rockslide. 相似文献
13.
Joseph Clancy White 《Contributions to Mineralogy and Petrology》1993,113(4):524-532
The textural relationships and structural states of optically isotropic labradorite from the Manicouagan, Quebec, impact structure have been examined by light (optical) and transmission electron (TEM) microscopy. Two distinct diaplectic glasses have been recognized based on their contrasting morphology, timing and the inferred modes of formation. The earliest isotropic bands and grain-scale isotropism (maskelynite) optically exhibit a gradational,in situ transformation from crystalline plagioclase with preservation of relict textures (twins, grain boundaries). The same transformation from crystalline to amorphous structure is observed in TEM to occur heterogeneously at scales on the order of the unit cell. The progressive transformation of optical properties reflects an increase in the volume fraction and eventual coalescence of these amorphous units. This maskelynite-type diaplectic glass is interpreted to form in the solid-state directly from crystalline material during the compressional phase of the shock wave. The other isotropic material occurs in spatially discrete tensiongashes and planar deformation features (PDFs) that overprint the maskelynite-type glass. This second type of diaplectic glass (PDF-type) is developed homogeneously within a given glass band and exhibits sharp crystal-glass boundaries, in contrast to the gradational boundaries of the maskelynite-type glass. PDF-type glass is interpreted to form by melting in tensional release zones during passage of the rarefaction wave. These observations emphasize the ability of naturally shocked rocks to preserve subtle evidence of variations in the shock process from highly transient events. 相似文献
14.
S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
15.
Xiaoyu ZHAO Wuyi WANG Hairong LI Fujian FENG Lizhen WANG 《中国地球化学学报》2006,25(B08):80-81
Brick-tea-type fluorosis is a peculiar endemic disease in China, which had been discovered in minority areas of western China since 1980, and distributed mainly in Tibet, Inner Mongolia, Gansu, Xinjiang, Qinghai and parts of Sichuan Province. The prevalence rate of fluorosis in Tibetan and Mongolian nationality people was higher. Epidemiological investigation showed that fluorosis morbidity and degrees were different in different brick-tea drinking areas, and it was probably caused by drinking various kinds of brick tea from different regions. Therefore, we collected 33 samples of brick tea from six provinces where minority nationalities were accustomed to drinking a large quantity of brick tea. F concentrations were determined by the combustion hydrolysis-ion selective electrode method. The results showed that among the brick teas, the F concentrations ranged from the minimum 74.1 mg/kg in Yunnan Province to the maximum 991.2 mg/kg in Sichuan Province. Besides, there was a great difference among the various kinds of brick tea, and F concentrations decreased in the order of Kang brick tea, Green brick tea, Black brick tea, Mi brick tea, Fu brick tea, Chitsu ping tea, Puerh tea, and Tuo tea. The average F concentration in brick teas was 431.92 mg/kg. 相似文献
16.
Natural Hazards - Despite the application of various methods to calculate uncertainty in flood vulnerability assessments, the challenge of uncertainty remains. The main purpose of this study was to... 相似文献
17.
L. I. Mashonkina A. B. Vinogradova D. A. Ptitsyn V. S. Khokhlova T. A. Chernetsova 《Astronomy Reports》2007,51(11):903-919
We derived Sr, Y, Zr, and Ce abundances for a sample of 74 cool dwarfs and subgiants with iron abundances, [Fe/H], between 0.25 and ?2.43. These estimates were obtained using synthetic spectra, assuming local thermodynamic equilibrium (LTE) for Y, Zr, and Ce, allowing for non-LTE conditions for Sr. We used high-resolution (λ/Δλ?40 000 and 60 000) spectra with signal-to-noise ratios between 50 and 200. We find that the Zr/Y, Sr/Y, and Sr/Zr ratios for the halo stars are the same in a wide metallicity range (?2.43 ≤ [Fe/H] ≤ ?0.90), within the errors, indicating a common origin for these elements at the epoch of halo formation. The Zr/Y ratios for thick-disk stars quickly decrease with increasing Ba abundance, indicating a lower rate of production of Zr compared to Y during active thick-disk formation. The thick-disk and halo stars display an increase in the [Zr/Ba] ratio with decreasing Ba abundance and a correlation of the Zr and Eu overabundances relative to Ba. The evolutionary behavior of the abundance ratios found for the thick-disk and halo stars does not agree with current models for the Galaxy’s chemical evolution. The abundance ratios of Y and Zr to Fe and Ba for thin-disk stars, as well as the abundance ratios within each group, are, on average, solar, though we note a slight decrease of Zr/Ba and Zr/Y with increasing Ba abundance. These results provide evidence for a dominance of asymptotic-giant-branch stars in the enrichment of the interstellar medium in heavy elements during the thin-disk epoch, in agreement with the predictions of the nucleosynthesis theory for the main s-process component. 相似文献
18.
Arsenic concentrations of less than 5 ppb to as large as 1,260 ppb in stream waters and from 5 ppm to 4,000 ppm in stream
sediments were found in the Pedro Dome-Cleary Summit area, Alaska. Waters from three of 20 wells sampled had arsenic concentrations
exceeding the U.S. Public Health Service recommended limit of 50 ppb. The high arsenic levels are a consequence of arsenic
enrichment in the rocks of the area. Placer and lode-gold mining may increase the arsenic content of the waters by exposing
arsenic-containing rocks to surface waters and by increasing the load of arsenic-rich sediments in the streams. Finding these
disturbingly large concentrations of arsenic in the waters of the Fairbanks area was the major result of this work, inasmuch
as a subsequent study (to be published) revealed arsenic concentrations as large as 10 ppm in domestic wells and prompted
an extensive study by Federal and State agencies of the health hazard posed by these arsenic-rich waters. 相似文献
19.