光谱特征提取对近似矿物光谱差异性影响分析

矿物光谱特征是基于光学遥感数据对矿物进行种类识别及定量反演的理论基础,光谱特征提取是高光谱数据常用的技术手段,但在多光谱数据中较少涉及。近似矿物识别是矿物光谱分类应用中的难点,目前还缺少有效指标来指示近似矿物类别光谱的差异性。光谱特征提取有望提高矿物分类精度,但该处理对近似矿物光谱差异性的影响还缺少相关研究。本文从矿物光谱差异性的原理出发,通过类间和类内光谱角的比值体现不同类别群体差异,并引入样本量因素,提出了类别可分比作为近似矿物光谱差异性的指标。以明矾石和高岭石两种近似矿物为例,对USGS光谱库光谱及Hyperion,ASTER,OLI等传感器的模拟数据进行光谱特征提取处理,通过对比处理前后矿物光谱差异性的变化,分析光谱特征提取对近似矿物光谱差异性的影响。实验结果表明,有效的光谱特征提取可以显著提高近似矿物光谱差异性,并且光谱分辨率越高,近似矿物光谱差异性越大。此外,光谱分辨率及中心波长设置对于包络线去除结果有很大影响,多光谱数据吸收特征提取效果有待进一步提高。该研究为今后近似矿物光谱识别精度的提高奠定了基础,也为未来新型遥感找矿传感器参数设置提供了参考。     

绿泥石矿物成分与光谱特征关系研究

绿泥石矿物广泛发育于各种岩石和地质环境中,其化学成分的变化,可反映出其形成时的物理化学条件及其光谱特征的变化。为了探索矿物光谱特征与其矿物化学成分间的内在关联性,为利用高光谱技术探测矿物微观信息提供基础依据。通过薄片显微分析,鉴定了岩石样品中的矿物种类及矿物组合特征,圈定出典型的绿泥石矿物颗粒和划分了绿泥石的产状特征;并利用现代电子探针微区分析技术,测定了16件岩石样品中共146个具有典型代表性的绿泥石矿物颗粒的化学成分,据此计算了其n(AlⅣ),n(AlⅥ),n(Fe),n(Mg)与Fe/(Fe+Mg)比值等相关化学参数;此外对测量的岩矿光谱进行分析,提取了岩石样品中绿泥石矿物的特征光谱参量。在以上基础上,对绿泥石矿物的光谱特征参量和其主要晶体化学参数的关系进行分析研究,研究表明绿泥石矿物的诊断性特征吸收波长位置随绿泥石中Fe离子含量的增加而向长波方向移动。研究结果对于利用高光谱遥感技术进行蚀变矿物及造岩矿物种类、成分及结构特征的识别和探测具有重要的指导意义。     

不同粒度条件下矿物光谱变化分析

矿物粒度是影响矿物光谱特征的一个重要因素,探索不同粒度下矿物光谱曲线的变化情况以及相同粒度下不同矿物的光谱差异,不仅是高光谱矿物遥感信息识别的关键,也为研究矿物随着粒度变化而产生的光谱差异提供理论基础。利用地物光谱仪对采集的六种矿物进行观测,获取了不同粒度下的反射率光谱曲线,同时生成一阶微分光谱曲线,进而分析了不同粒度下各种矿物的光谱变化特征,对比了相同粒度下不同矿物的光谱差异,探索高光谱遥感识别矿物的可能波段。结果表明：各种矿物的光谱曲线均会随着粒度的改变而产生较大的差异,但变化规律不尽相同,紫苏辉石的整条光谱曲线都会随着粒度的增加而下降,叶蛇纹石、赤铁矿、高岭石、绿泥石的光谱曲线在特定的波长范围内随着粒度的增加而下降,橄榄石的光谱与粒度大小不存在直接的相关性;相同粒度下,不同矿物的光谱反射率在大部分波段范围内差异较大,为实现矿物高精度识别提供了可能;叶蛇纹石、高岭石、绿泥石具有较多的宽度较窄、强度较小的吸收峰,而赤铁矿、橄榄石、紫苏辉石的光谱曲线相对平滑,吸收和反射峰的数量较少。本研究旨在为矿物光谱库的构建以及矿物的高光谱技术识别提供基础数据和理论支撑。     

基于多类型光谱特征参数匹配的矿物信息遥感识别方法

传统的与光谱反射率匹配的矿物填图方法受图像质量、大气及环境背景等因素影响较为明显,矿物识别效果较差。针对上述问题提出一种基于多类型光谱特征参数匹配的矿物信息识别方法,综合利用多种光谱特征参数在大气及环境背景变化中的相对稳定性特点,实现矿物信息的高精度识别。选取美国内华达州Cuprite矿区AVIRIS机载可见-红外光谱成像仪高光谱数据,以USGS美国地质调查局波谱库中的矿物波数为参照光谱,分别计算AVIRIS影像和USGS波谱库中典型矿物的光谱特征参数,在对多种光谱特征参数综合分析的基础上,构建Cuprite矿区矿物识别模型,进行矿物填图实验。最后使用Clark等在该地区的矿物填图结果数据,对实验结果进行了验证,结果表明：该方法矿物识别结果与Clark等的填图结果吻合度高,整体矿物识别精度达到78.96%。     

基于拉曼光谱的复杂硫化矿快速分类方法研究

热液硫化物型脉状矿作为一类复杂硫化矿,其区域特征、成矿规律及矿物成份已有初步研究。由于成矿时期的不同,矿石中有用矿物的特征存在较大差异,导致不同矿物的性质变化较大。在选矿过程中,矿物性质的差异一定程度增加了选矿难度,减少了有用矿物回收率。因此,迫切需要一种快速、简单的对复杂硫化矿进行分类的方法,进而提高选矿指标。激光拉曼光谱技术作为一种能够分析物质结构信息的手段,已被应用于矿物的成份鉴定和结构分析。通过对大量矿物样本的激光拉曼光谱的研究,结合矿物性质深入揭示其光谱差异的原因,提出了一种基于拉曼光谱的复杂硫化矿矿源分类方法。实验结果表明：由于此类复杂硫化矿成矿时期的差异,从而造成矿物结构和性质存在较大差异。荧光主要由原矿中的脉石矿物产生,猝灭矿物中瞒石的荧光背景后可知201.62, 242.54, 288.38和309.77 cm-1处拉曼峰可以作为此类硫化矿的拉曼指纹谱。为此,基于此类硫化矿的荧光强度和代表谱峰强度与荧光背景比值可以将矿源分为三类,并利用工业试验结果进一步验证分类方法的准确性。本研究深入分析了此类复杂硫化矿的激光拉曼光谱与其矿物性质与类别之间的密切关系,提出了矿源快速分类方法,矿样无需经过复杂的化学前处理过程,对提高选矿作业效率具有重要应用价值。     

碱土-铈氟碳酸盐矿物晶体结构中的无序堆垛和交生

用晶格象技术研究了同时含有钙和钡的铈氟碳酸盐矿物,发现这类矿物的晶体是由不同组分的钙-铈氟碳酸盐矿物和不同组分的钡-铈氟碳酸盐矿物单层无序堆垛而成,在百埃数量级的范围内,观察到不同组分钙-铈氟碳酸盐矿物的交生现象,由此提出伦琴钙铈矿可能有一种新的多型体。研究结果显示了晶格象技术直接观察这类矿物晶体结构的优越性。 关键词：     

内蒙古维拉斯托锌铜多金属矿床深部断层泥特征及其意义

在维拉斯托矿区深部矿井的不同中段共采集了六组断层泥样品,采用X射线衍射和近红外光谱现代测试分析技术对样品进行分析测试,旨在探讨断层泥的矿物成分特征及其与成矿作用关系。分析结果表明,(1)断层泥中含有低温蚀变的粘土矿物(如蒙脱石、高岭石、地开石、绿泥石等)和中高温热液蚀变矿物(如石墨、黑云母、叶腊石、重晶石、蛇纹石、透闪石、阳起石等),同时也含有与成矿作用密切相关的矿物成分(如铜锌氧化物、氯铜钒、蓝铜矿、斑铜矿等)。(2)不同深度的断层泥矿物成分有所不同,地表浅部以浅变质矿物为主,深部以变质程度较深的矿物为主。(3)从断层泥矿物成分、矿物成因及发展演化规律来看,断层泥主要形成于含矿热液活动时期及矿后构造,且后期经历了表生氧化作用。(4)通过分析断层泥蚀变矿物成分及其矿物组合特征可以推测,该矿床形成于中-高温热液环境下,经历了硅化、高岭石化、绿泥石化、萤石化及绢云母化等蚀变过程。因此,通过分析断层泥的矿物成分及其矿物组合特征,不仅对指导找矿有一定的现实意义,同时也可以对矿床成因类型的判断提供重要的参考信息。     

四川平通512地震地表破裂带土壤近红外光谱分析及意义

在四川省平武县平通镇的512地震地表破裂带中采集黄色土壤样品,采用现代近红外光谱分析技术进行分析测试。通过对土壤中的矿物微粒特征吸收峰的快速鉴别,表明土壤样品主要由方解石、白云石、白云母、绢云母、伊利石、蒙脱石、滑石、透闪石、阳起石、绿泥石等矿物组成,其矿物成分与四川地区分布的黄壤成分基本一致。分析对比发现,土壤中的部分矿物与破裂带下部岩体的矿物组成特征相符合,说明该破裂带中的部分土壤矿物的演化与该地区岩石的矿物组成密切相关;地表破裂带土壤中的粘土矿物组成与北方的马兰黄土相似,推测这两种土壤中的粘土矿物可能具有相似的成因。研究结果说明近红外土壤矿物的分析技术可以有效分析土壤中的矿物微粒、指示成土环境,从而论证了将近红外光谱分析技术应用于土壤矿物的快速分析、地质研究的可行性。同时研究结果可以成为该地区土壤矿物分析的基础,为以后的土壤矿物以及地震破裂带的研究提供新的思路和方法。     

利用CCSEM对煤中矿物特性及其燃烧转化行为的研究

利用计算机控制扫描电镜技术(Computer Controlled Scanning Electron Microscopy,CCSEM)研究了煤中矿物特性及其在燃烧过程中的转化行为.结果表明原煤中矿物主要为粘土和黄铁矿,且主要以外在矿物的形式存在,粒径多在10 μm以上,而内在矿物绝大部分小于10 μm.不同矿物具有不同的粒径分布和内在/外在特性,显示煤中矿物分布的非均一性.煤灰主要由莫来石、铁、钙和钠的铝硅酸盐组成.通过K、Fe、Ca和Na在原煤及其产物所含矿物中的质量分布对比,揭示了它们在燃烧过程中的转化行为.煤灰粒径的变大是矿物颗粒熔融聚合的结果.     

一种红外光谱免疫计算的矿物组分定量提取方法

近红外/短波红外光谱的矿物组分快速鉴定技术可以大大提高野外矿产勘查、遥感矿物填图、岩芯矿物组分分析等工作的效率,成为目前高光谱技术研究的热点之一。文章给出了一个基于光谱相似度评价约束的联合目标岩石样品光谱和矿物光谱端元库进行矿物组分光谱反演的统一模型,然后以矿物光谱线性混合模型和光谱夹角相似度评价为例,建立了一个具体的组分反演模型;针对模型求解过程中的组合优化问题,提出了一种人工免疫克隆选择计算的矿物组分光谱(ICSFSLIM)识别方法;利用在中国新疆包古图地区选取的22个野外岩石样品的实测近红外/短波红外光谱进行了矿物组分提取试验,以样品薄片鉴定结果为准,将ICSFSLIM识别结果与组合特征光谱线性反演模型(CFSLIM)识别结果进行了定量的对比分析。结果表明：ICSFSLIM比CFSLIM的识别正确率提高了2.26%,有效率提高了18.6%,并且具有更高的识别稳定性。     

网纹红土中铁矿物与粘土矿物赋存关系的X射线衍射证据

高纯度的粘土矿物样品是粘土矿物学重建古气候的关键,然而,土壤中的铁矿物(如针铁矿和赤铁矿等)和有机质的存在导致粘土矿物与非粘土矿物相互包裹,使富集的粘土矿物样品常含有其他矿物杂质。土壤沉积物中有机质去除的研究已较为充分,但铁矿物在土壤沉积物中的赋存状态倍受争议,制约了高纯度粘土矿物样品的制备。该研究将以长江中下游九江网纹红土作为研究对象,通过逐级分离试验对网纹红土中铁矿物与粘土矿物的赋存关系进行研究,为土壤沉积物中铁矿物的去除提供一定的启示。试验结果表明,针铁矿和赤铁矿等铁矿物可能主要呈现被膜状吸附在羟基间层蒙脱石和伊利石的表面,也有部分被高岭石吸附。     

Ac conductivity and dielectric behavior of hydrated homoionic alkali-cations-exchanged montmorillonite

The dielectric properties of a series of homoionic alkali-exchanged montmorillonites were studied at different treatment temperatures and various water loadings by means of complex impedance spectroscopy. To date, however, this method has been underutilized in clay minerals studies. The main objective of the present work is to understand the relaxation mechanisms of water molecules interacting with different hydration centers in clay minerals, with a view to eventually control their interactions with the alkali extra-framework cations. The other part of our study is to study the dielectric properties such as real and imaginary parts of dielectric permittivity, loss tangent, and ac conductivity in the frequency range 10^?2–10⁶?Hz and temperature range 173–333?K of these clay minerals. The obtained results have been discussed in terms of the Jonscher model.     

Analysis on air suspended particles of Coimbatore — a FTIR study

An infrared absorption method has been used to identify the minerals in dust collected from some parts of Coimbatore, Coimbatore district, Tamil Nadu without grinding. The KBr pellet technique was employed. The results obtained from the IR spectra show the presence of quartz, asbestos, kaolinite, calcite, haematite, montmorllonite, nacrite and coal. The hazardous effect of inhalation of these minerals are explained. The results show Pollachi main road is more contaminated with hazardous minerals.     

Oscillatory zoning caused by oscillating surface relaxations

Oscillatory zoning is a spatial variation in the composition of minerals. It has been observed in many different minerals and a variety of mechanisms have been proposed to explain it. We propose an equilibrium model of oscillatory zoning in which the variations in composition stabilise a ferroelastic phase. This results in a sinusoidal variation in composition. We expect that this mechanism could account for oscillatory zoning found in minerals with oscillatory surface relaxations. Received 9 March 1999     

Documentation and evaluation of Mössbauer data for minerals

More than 2,500 Mössbauer spectroscopic studies on minerals have been published since 1960. These papers contain approximately 8,000 sets of Mössbauer mineral data on at least 400 different minerals. This information has been compiled into a database that includes isomer shifts, quadrupole splittings, and magnetic hyperfine interactions at room, liquid nitrogen, and liquid helium temperatures. The database provides a profile of the Mössbauer research performed to date on minerals, including type and locality of minerals investigated, significance of the studies and results, and location of the research facilities. The data and information are available both in printed and magnetic form. With the establishment of this resource, the Mössbauer Effect Data Center has begun a systematic evaluation of the Mössbauer mineral data. It is anticipated that this resource can be used for the identification of minerals as powder X-ray diffraction data is.     

Radiation resistance of LaPO4 (monazite structure) and YbPO4 (zircon structure) from data of computer simulation

The radiation resistance of the monazite LaPO₄ and the compound YbPO₄ (zircon structure type) has been investigated using the computer simulation. The number of Frenkel pairs, which are formed in the structure of these minerals after the passage of a primary knock-on thorium atom with an energy of 30 keV, has been calculated by the molecular dynamics method. The formation of Frenkel pairs and their recombination in the motion of recoil nuclei in the structure of the studied minerals have been discussed. It has been shown that the probability of the “survival” of Frenkel pairs in the LaPO₄ monazite is significantly lower than in the YbPO₄ compound. The tendency of these minerals toward amorphization under radiation damage has been described numerically. The obtained results have demonstrated that one of the main factors determining the radiation resistance of orthophosphates LnPO₄ is the type of crystal structure, and the compounds with the monazite structure are more radiation resistant than the compounds with the zircon structure.     

ICP-AES法测定茶叶、茶水中的矿物质和微量元素

本文用电感耦合等离子体原子发射光谱法（ICP－AES）对不同品种，不同等级及不同产地的茶叶、茶水样品中的一些人体所必需的矿物质和微量元素进行了定量测定。结果表明，该方法简便，可靠，具有良好的精密度和准确度，本研究将对茶叶中一些矿物质和微量元素的鉴定以及在饮茶爱好者的合理购茶、饮茶等方面提供一些有用的信息。     

Uranium estimation in pegmatities using solid state track detector

Homogenised fission track analysis has been used to determine the uranium abundances in common minerals and rocks of Pegmatite deposits. Lexan Polycarbonate detector has been used to register fission tracks from the thermal neutron induced fission of uranium. The purpose of the work is to illustrate the usefulness of the solid state track detector method and to present preliminary data on uranium contents in mineralizations of possible future economic importance. Most of the minerals have uranium concentration less than 1 PPM, but some minerals contain as much as 30 PPM uranium.The authors are grateful to Dr. R. Parthasarthy, Analytical Chemistry Division, B.A.R.C. Trombay, Bombay, Shri R. H. Khan, Director of Geological Survey, Nepal and Shri S. M. Hassan, Joint Director, Directorate of Geology and Mining (J. & K. State) for the supply of samples.     

A preliminary approach to identify irradiated foods by thermoluminescence measurements

Thermoluminescence (TL) is one of the physical methods for the identification of irradiated foods. Among the currently developed methods, TL is the most widely used method for the identification of irradiated foods. However, in order to use this method, silicate minerals should be isolated from food samples. The process for the isolation of silicate minerals is time consuming and laborious. In this work, we have investigated the applicability of the TL method using iron-containing minerals instead of silicate minerals. In the TL analyses of dried spices, TL glow curves of iron-containing minerals showed maximum temperatures between 150 and 250 °C which were the same as those of silicate minerals. The process for the mineral separation of the proposed method is simple, fast, easy, and reliable. Moreover, the analysis results including TL ratio have not shown significant differences compared with the silicate minerals method. As a result, the TL measurements using the iron-containing minerals could be an excellent method for the identification of the irradiated foods, including dried spices.