辽宁岫岩玉的组成和性质的研究   总被引：1，自引：0，他引：1  

张良钜 《矿物学报》2002,22(2):137-142

辽宁岫玉主要是由叶蛇纹石组成 ,其叶片大小多为 30 0nm× 4 4 0nm左右 ,沿a轴方向呈波状层结构。岫玉中的矿物生成先后次序为粗粒透闪石 细粒透闪石 滑石 叶蛇纹石。岫玉中的颜色和透明度明显受TFeO含量及Fe2 O3/FeO比值所制约 ,同时岫玉中的杂质包裹体 (透闪石、滑石、黄铁矿、磁黄铁矿 )对岫玉的颜色、透明度和其它性质 (光泽、硬度、抗压和抗折强度 )也有直接的影响。  相似文献   

Magnetic phase diagrams of Mg-, Fe-, (Cu + Ti)- and Cu-substituted braunite Mn<Superscript>2+</Superscript>Mn<Subscript>6</Subscript><Superscript>3+</Superscript>SiO<Subscript>12</Subscript>     

I. Abs-Wurmbach  S. Ohmann  K. Westerholt  Th. Meier  P. Mouron  J. Choisnet 《Physics and Chemistry of Minerals》2002,29(4):280-290

 The magnetic behavior of the Jahn-Teller structure braunite, (Mn²⁺ _1−yM _y )(Mn³⁺ _{6− x} M_x)SiO₁₂, is strongly influenced by the incorporation of elements substituting manganese. Magnetic properties of well-defined synthetic samples were investigated in dependence on the composition. The final results are presented in magnetic phase diagrams. To derive the necessary data, ac susceptibility and magnetization of braunites with the substitutional elements M = Mg, Fe, (Cu+Ti) and Cu were measured. Whereas the antiferromagnetic ordering temperature, T _N , of pure braunite is hardly affected by the substitution of nonmagnetic Mg, it is rapidly suppressed by the substitution of magnetic atoms at the Mn positions. Typically for a concentration (x, y) ≥ 0.7 of the substituted elements, a spin glass phase occurs in the magnetic phase diagrams. Additionally, for the braunite system with Fe³⁺ substitutions, we observe in the concentration range 0.2 < x< 0.7 a double transition from the paramagnetic state, first to the antiferromagnetic state, followed by a transition to a spin glass state at lower temperatures. The unusual change of the magnetic properties with magnetic substitution at the Mn positions is attributed to the peculiar antiferromagnetic structure of braunite, which has been resolved recently. Received: 19 April 2001 / Accepted: 6 September 2001  相似文献   

西藏蛇绿岩的超高压矿物：FeO、Fe、FeSi、Si和SiO2组合及其地球动力学意义   总被引：12，自引：1，他引：12  

白文吉  杨经绥  方青松  颜秉刚  张仲明 《地球学报》2002,23(5):395-402

在西藏雅鲁藏布江蛇绿岩带的东段，出露罗布莎蛇绿岩块和豆荚状铬铁矿床。从豆荚状铬铁矿石中查明60－70种伴生矿物，其中包含FeO、Fe、FeSi、Si和SiO2组合。根据超高压－高温实验，该组合应形成于地球外核与下地幔之间的D“层，是地球外核的液态铁与镁硅酸盐钙钛矿（MgSiO3)相互化学反应的产物。西藏该超高压矿物组合揭示了蛇绿岩地幔活动可能深达地球外核。罗布莎蛇绿岩的该矿物组合可能是地幔－外地核之间的产物，或者是被对流作用，亦是被起源于D“层的地幔柱活动带到上地幔的。铬铁矿在地幔中结晶，并捕获了该矿物组合。  相似文献   

MUEBLES RÚSTICOS IN MEXICO AND THE UNITED STATES     

JOHN HARNER 《Geographical review》2002,92(3):354-371

ABSTRACT. Sales of muebles rústicos, or rustic wooden furniture made in Mexico, have grown rapidly in the United States since 1994. Analysis of the recent rise of the industry tracks manufacturing and marketing methods in major production areas of Mexico. Consumer taste for “authentic” handmade goods of simple design and the vogue of the “Santa Fe” style across the American Southwest mesh with Mexican producers' need to seek foreign markets during an economic crisis. Changing style preferences, along with the furniture's handcrafted appearance, its competitive cost, and the makers' flexible production methods, are reasons for the increased popularity of this folk commodity.  相似文献   

松嫩平原典型土壤高光谱定量遥感研究   总被引：5，自引：0，他引：5  

刘焕军  张柏  刘殿伟  王宗明  宋开山  杨飞 《遥感学报》2008,12(4)

为实现松嫩平原典型土壤理化参数时空信息的快速获取,为定量遥感、精准农业等相关研究服务,以松嫩平原典型土壤的高光谱反射率为研究对象,分析土壤反射光谱特征及其与土壤理化参数的关系,建立基于反射光谱指数的土壤理化参数遥感估算模型;提取黑土光谱特征点,建立黑土反射光谱曲线模拟函数.结果表明:松嫩平原不同土壤光谱特征差异主要在450-600,600-800 nm两个吸收谷部分,土壤有机质是黑土反射光谱特征的决定因素;不同于南方土壤,铁对松嫩平原典型土壤反射光谱特征的影响较小;随着含水量的增加,土壤水分对土壤光谱反射率的作用过程可以用三次方程定量描述;基于土壤反射率及反射光谱特征的土壤理化参数光谱预测模型可以用于土壤相关理化参数的快速测定;基于光谱特征点的黑土反射光谱曲线模拟函数可以准确描述黑土的反射光谱特征,这一方法可以用于高光谱数据压缩和基于多光谱数据的高光谱反射率重建.  相似文献   

青海祁漫塔格地区铁多金属成矿特征及找矿潜力   总被引：1，自引：0，他引：1  

潘彤 《矿产与地质》2008,22(3):232-235

祁漫塔格地区是青海省重要的铁多金属矿产地,其成矿作用主要为喷流-沉积作用,矿产伴生有益组分多,根据成矿地质条件、地球物理资料分析,该地区铁矿资源仍具有较大的找矿潜力,为柴达木国家级循环经济试验区建设的基础。  相似文献   

保山金厂河大型铜铁多金属隐伏矿床   总被引：3，自引：1，他引：2  

周荣  陈均  吕永增  董文伟 《云南地质》2008,27(2):189-196

隐伏矿床位于金厂河隆起核部上、下两层矽卡岩化带中,垂向上Pb、Zn—Cu、Cu、Fe—Fe多层楼结构,水平上Fe、Cu—Pb、Zn—Cu分带。属热液交代矽卡岩型铜铁多金属矿床。  相似文献   

京西煤系高岭土中铁、钛赋存状态研究   总被引：1，自引：0，他引：1  

杨晓杰  刘冬明  李桂刚  陈开惠 《地球学报》2006,27(2):141-144

本文以分析电子显微术为主要技术手段,对京西煤系高岭土中铁、钛物相的赋存状态进行了深入研究。结果表明,京西高岭土精矿中含有少量锐钛矿和微量针铁矿及铁钛混合物相;结构铁是京西煤系高岭土中铁的主要存在形式,其中也含有微量结构钛。四次配位于硅氧四面体中的Fe3 和存在于铝氧八面体中六配位的Fe3 和Fe2 是结构铁的三种占位形式。研究结果对于深化煤系高岭土的矿物学研究和京西煤系高岭土的开发利用具有重要理论意义和指导意义。  相似文献   

UV-Vis spectrophotometric and XAFS studies of ferric chloride complexes in hyper-saline LiCl solutions at 25-90 °C     

Weihua Liu  Barbara Etschmann  Leone Spiccia  Brent McInnes 《Chemical Geology》2006,231(4):326-349

The speciation and thermodynamic properties of ferric chloride complexes in hydrothermal solutions and hypersaline brines are still poorly understood, despite the importance of this element as a micronutrient and ore-component. Available experimental data are limited to room temperature and relatively low chloride concentrations. This paper reports results of UV-Vis spectrophotometric and synchrotron XAFS experiments of ferric chloride complexes in chloride concentrations up to 15 m and at temperatures of 25-90 °C. Qualitative interpretation of the UV-Vis spectra shows that FeCl²⁺, FeCl₂⁺, FeCl_3(aq) and FeCl₄⁻ were present in the experimental solutions. As chloride concentrations increase, higher ligand number complexes become important with FeCl₄⁻ predominating in solutions containing more than 10 m at 25 °C. The predominance fields of FeCl_3(aq) and FeCl₄⁻ expand to lower Cl concentrations with increasing T. Both XANES and UV-Vis spectra reveal a major change in the geometry of the complex between FeCl₂⁺ and FeCl_3(aq). EXAFS data confirm that the number of chloride ligands increases with increasing chloride concentration and show that Fe³⁺, FeCl²⁺ and FeCl₂⁺ share an octahedral geometry. FeCl_3(aq) could be either tetrahedral or trigonal dipyramidal, while FeCl₄⁻ is expected to be tetrahedral. EXAFS data support a tetrahedral geometry for FeCl₄⁻, especially at 90 °C, but do not allow to distinguish between a tetrahedral or trigonal dipyramidal geometry for FeCl_3(aq) because of similar Fe-Cl distances. At room temperature, EXAFS data suggest that FeCl_3(aq) may be a mixture of octahedral and tetrahedral or trigonal dipyramidal forms.The room temperature formation constants for three ferric chloride complexes (FeCl₂⁺, FeCl_3(aq) and FeCl₄⁻) determined from the UV data are generally in good agreement with previous studies. Calculations based on the properties extrapolated to 300 °C show that hematite solubility is much higher than previously estimated, and that the high orders complexes FeCl_3(aq) and FeCl₄⁻ are important at high temperatures even in solutions with low chloride concentrations. The accuracy of these properties is limited by a poor understanding of activity-composition relationships in concentrated electrolytes, and by limitations in the available experimental techniques and extrapolation algorithms; however, the inclusion of higher order complexes in numerical models of ore transport and deposition allows for a more accurate qualitative prediction of Fe behaviour in hydrothermal and hypersaline systems.  相似文献   

太平洋中国开辟区锰结核生物成因研究   总被引：13，自引：2，他引：11  

陈建林  张富生等 《地质学报》2001,75(2):228-233,T005,T006

本文对叠层石（微小叠层石与奇异叠层石）及其建造者（中华微放线菌与太平洋螺球孢菌）在结核中显示的规律性特征,叠层石纹层与超微生物生长,主要锰矿物及Fe、Mn元素与叠层石类型之间关系以及超微生物直接成矿等作了深入研究。结果表明：锰结核中叠层石柱体一般都显示出纹层、纹层组与纹层带3个级别的生长韵律,明层菌丝体密集,暗层菌丝体稀疏;两种叠层石类型与超微生物化石种存在着良好的对应关系;主要锰矿物含量变化与叠层石类型密切相关;叠层石柱体内Fe、Mn元素分布比柱间空隙具有明显的规律性,而全球性大气化程度比生殖菌丝强;超微生物的生化作用与沉积粘附作用直接造成了结核中Fe、Mn元素的富集,而全球性大气修与洋底微环境的周期性变化,影响了微生物生长的兴衰,导致了明暗相间纹层的交替出现。我们认为,叠层石纹层显示的韵律性特征,是胶体化学作用与沉积作用难以形成的,只有微生物群体的世代繁衍,才能构筑成几乎固定不变的叠层石柱体形态。上述研究成果,进一步确立了大洋锰结核的生物成因观点。  相似文献