Allende碳质球粒陨石中某些斜长石的阴极发光现象及其产生的机理

对Allende陨石的富钙铝包裹体中的斜长石,用电子探针和扫描电镜进行阴极发光的研究。作者对三颗生长在富钙铝包裹体中无尖晶石区域内的斜长石晶体进行了详细的研究。在电子束的轰击下它们都显示出深、浅蓝色的阴极发光带。电子探针定量分析表明,在深蓝色发光带中,杂质元素Na和Mg的含量较高(约为500～1000ppm),而在浅蓝色发光带中,Na、Mg含量相对较低(约为100～500ppm),同时Na的含量与Mg的含量呈正相关。 矿物中微量杂质的存在与矿物的阴极发光之间存在着某些规律性的联系,因此矿物的阴极发光可以作为研究矿物的一种特殊标志。此外,不同微量元素的存在也可以给出某些成因信息。 本文对引起阴极发光的物理机制也进行了讨论。     

Special Xenoliths in an Aegirine-Augite Syenite Porphyry in Liuhe, Yunnan, China： Discovery and Implications

Three special types of xenoliths have recently been found in an aegirine-augite syenite porphyry in Liuhe,Yunnan,China.Petrographical,petrochemical,electron microprobe,and scanning electron microscopy studies indicate that pure calcite xenocrysts and quartz-bearing topaz pegmatite xenoliths result from the degassing of mantle fluids during their migration,and that black microcrystalline iron-rich silicate-melt xenoliths are the product of the extraction of mantle fluids accompanying degassing and are com...     

Mineralogical features and genesis of Polyanskoye mercury deposit on Chukotka

The mineralogy of two gold deposits in southwestern China, which contain gold entirely in the form of microscopic or submicroscopic grains or inclusions, is examined. They contain refractory or low-grade ores similar in type to those near Carlin, Nevada. Mineralogical studies of ore samples from the two deposits (e.g., proton microprobe analysis, scanning electron microscope analysis, electron microprobe analysis, X-ray diffraction studies, ore microscopy) indicate that the predominant gold-bearing minerals are pyrite (Dongbeizhai deposit) and arsenopyrite and pyrite (Jinya deposit). Gold in the two deposits is closely correlated with As, S., and Fe.     

Fine-scale chlorite-muscovite association in low-grade metapelites from Nurra (NW Sardinia), and the possible misidentification of metamorphic vermiculite

Chlorite-muscovite porphyroblasts occur in the low-grade metapelites from Nurra (NW Sardinia). Although actually heterogeneous and built up by two different intermixed minerals, the porphyroblasts strongly simulate optical homogeneity and produce microprobe analyses that are typical for metamorphic vermiculite. Transmission and scanning electron microscopy, combined with analytical facilities, leads to a deeper characterization of the porphyroblasts, that actually consist of a random association of chlorite and muscovite.As a further result, the present study also shows that the existing criteria used to identify metamorphic vermiculite, namely optical features and microprobe composition do not warrant the correct identification.Finally, the present results once more confirm the importance of back-scattered electron imaging in the SEM as a powerful tool for the routine petrographic study of sedimentary and low-grade metamorphic rocks.     

Occurrence of Uraniferous Iron Grains at Gabal Gattar, El Missikat and El Erediya Granites in Eastern Desert of Egypt

Uraniferous iron grains occur in some radioactive granite plutons in the Eastern Desert of Egypt. Modal analysis of these grains indicates that weight abundance of uraniferous grains amounts to 17.50%, 18.00% and 26.00% of the total accessory heavy minerals of the uranium-mineralized samples of Gabal Gattar, El Missikat and El Erediya, respectively. These grains are mainly restricted to shear zones associated with strong hematitization, and occur either as fracture fillings or as interstitial grains among the main rock-forming minerals. Uraniferous iron grains are mainly composed of uranophane and β-uranophane coated and stained with limonite. These grains represent the main radioactive minerals in addition to the bright canary yellow to yellow uranophane and β-uranophane mineral grains. The data obtained on scanning electron microscopy and electron microprobe analysis confirm the abundance of iron in the darker colored varieties with respect to the light colored varieties. This mode of occurrence of the uranium minerals requires special consideration during mineral processing by physical means.     

Special Xenoliths in an Aegirine–Augite Syenite Porphyry in Liuhe, Yunnan, China: Discovery and Implications

Three special types of xenoliths have recently been found in an aegirine–augite syenite porphyry in Liuhe, Yunnan, China. Petrographical, petrochemical, electron microprobe, and scanning electron microscopy studies indicate that pure calcite xenocrysts and quartz-bearing topaz pegmatite xenoliths result from the degassing of mantle fluids during their migration, and that black microcrystalline iron-rich silicate-melt xenoliths are the product of the extraction of mantle fluids accompanying degassing and are composed dominantly of quartz, chlorite, and iron-rich columnar and sheet silicate minerals with characteristic minerals, such as native iron, apatite, and zircon. According to the bulk-rock chemical and mineral compositions and crystallization states, the microcrystalline melt xenoliths are not the product of conventional magmatism, and especially the existence of native iron further proves that the xenoliths were mantle fluid materials under reduction or anoxic conditions. The study of the special xenoliths furnishes an important deep-process geochemical background of polymetallic mineralization in different rocks and strata in the study area.     

甘肃岷县寨上特大型金矿次显微金的赋存状态研究

寨上金矿是一微细浸染型超大型金矿床。通过光学显微镜、人工重砂、电子探针、扫描电镜等显微测试手段对寨上矿区主要载金矿物进行分析测试得出：黄铁矿、白钨矿是最主要的载金矿物之一,石英、褐铁矿、辉铜矿是次要的载金矿物．方解石、菱铁矿、重晶石等不含金。由于受检测手段所限,在含金黄铁矿、白钨矿、石英等矿物中未发现独立金颗粒,所以寨上金矿次显微金呈微包裹体形式存在于载金矿物中或呈类质同象替代的原子形式存在。通过研究主要载金矿物黄铁矿中Au、As的关系得出：Au与As呈正相关关系;从具有增生环带结构黄铁矿的内核向增生体S、Fe呈对数下降趋势,Au、As呈对数上升趋势。对比沉积期、热液期形成的黄铁矿主量、微量元素得出S、Fe变化不大,微量As呈线性递增,而Au呈线性递减。     

Clausthalite in coal

A lead selenide mineral, tentatively identified as clausthalite (PbSe) based on optical microscopy, scanning electron microscopy with energy-dispersive X-ray (EDAX), electron microprobe, and scanning proton microprobe (SPM), has been described in a number of coals. While clausthalite has been mentioned as a possible source of Se in coal, it is present in such small quantities and sizes, that the mineral identification has not been absolutely confirmed. The mineral specimens examined in this study would contribute, not only to the Pb and Se concentrations in the coal, but also, in at least one case, to Hg concentrations.     

细微矿物拉曼成像分析技术与方法研究

岩矿鉴定是各类地质工作开展的基础,其鉴定水平和质量直接影响着工作的深入程度和研究程度。传统鉴定方法受人员自身经验水平、光学显微镜分辨率等因素的影响较大,对于现今需要研究的细微稀有矿物、细粒沉积岩矿物等很难准确地识别鉴定。而依托高精密大型仪器的技术方法多数对样品制备有特殊要求,不利于样品的再利用,诸如扫描电镜、电子探针等在高倍数反射光下探寻、观测特定的细微透明矿物也存在一定的不足。本文将激光拉曼高分辨大面积快速成像方法（StreamLineHR）运用于两块标准岩石光薄片的全区域大面积扫谱,准确识别出其中透明矿物有碱性长石、斜长石、石英、普通角闪石、黑云母、方解石、榍石、磷灰石、锆石和绿帘石,不透明矿物有磁铁矿,部分矿物间存在紧密伴生的情况（如石英与长石、榍石与角闪石）和次生蚀变的情况（如长石碳酸盐化蚀变为方解石）。并以此为基础进行了含量统计,将其分别定名为细粒角闪石英二长闪长岩与细粒黑云母斜长角闪岩。实验过程中,荧光效应,类质同象类矿物（长石、角闪石）峰位相似性和蚀变矿物峰位偏移会对矿物识别、谱图解析造成干扰,可结合矿物镜下光性特征来解决。另外,面扫步长设置越小,分析精确度越高,时间成本也会相应增加,应用时需兼顾考虑。该方法实现了对细微矿物便捷、直观、准确的大范围快速识别鉴定,可弥补传统岩矿鉴定和其他技术方法的不足,拓展了拉曼光谱法在地质工作中的应用范围。     

类质同象的研究方法及意义

结合研究史作者论述了元素类质同象、间隙原子和固溶体概念的异同。指出类质同象元素的3个属性：同生性、共生性和同晶体化学位。提出元素统计式均匀分布为鉴别类质同象状态的理论准则,例举电子探针、矿物物性鉴别“杂质”属性的可行性,指出电子探针方法为最佳选择。论述了类质同象的重要地学意义：岩浆演化的指示剂和地质温压计。提出类质同象副成分作为找矿地球化学标志的新思路。元素不同存在状态的查定在矿产资源评价中具有重要意义。     

激光探针—新的稳定同位素分析方法

简要地比较了ＣｌＦ３和ＢｒＦ５两种常规氟化法的优缺点。在此基础上介绍了激光氟化法（又称激光探针法）的主要构成和特点以及激光探针法的分析精度和分析不同矿物时的特点。激光探针法具有样品处理简单、用量少、速度快和可作原位分析等优点。激光探针法的使用为地幔氧同位素系统的研究勾画了一幅新的图景；在微区同位素分析、交换反应动力学等方面也展示了良好的应用前景     

Mineralogical investigations in the interpretation of heavy-mineral geochemical results from till

Heavy-mineral geochemistry and its use in prospecting are based on the fact that some ore minerals (e.g. cassiterite, scheelite, wolframite, chromite, pyrochlore and columbite-tantalite) have a higher specific gravity than the common rock-forming silicates and are highly resistant to weathering in the secondary environment. Till, the most common type of surficial deposit in Finland, is relatively homogeneous and thus constitutes an appropriate sampling material for heavy-mineral geochemical studies. This is especially true in reconnaissance prospecting.The present work concentrates on the interpretation of heavy-mineral anomalies by reference to mineralogical and mineral chemistry data. Tetrabromoethane and a Frantz Isodynamic Separator were used to divide the heavy-mineral samples into subfractions, after which the minerals present were identified by light microscopy, scanning electron microscopy combined with energy-dispersive X-ray spectrometry, electron microprobe techniques and X-ray diffraction.Applications of the methods at three tin anomaly sites in southern Finland are described. The results successfully predicted the presence of a greisen in one area and a pegmatite in another. Those for the third area were somewhat contradictory, the mineralogical composition of the samples suggesting a greisen source for the tin while the composition of the cassiterite pointed to a pegmatite or granite source.     

Mineral/water interactions in tailings from a tungsten mine, Mount Pleasant, New Brunswick

The pore-water geochemistry and mineralogy of tailings derived from a granitic tungsten deposit were characterized by collecting pore-water samples at discrete depth intervals throughout the tailings for the analysis of major and minor element concentrations. Mineralogical samples from the oxidation zone were analyzed by X-ray diffraction, scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM/EDS), electron microprobe (EMP) combined with wavelength dispersive X-ray spectroscopy (WDS), and transmission electron microscopy (TEM). The oxidation of sulfide minerals in the near-surface tailings leads to a decrease in pore-water pH and elevated SO₄, As, and metal concentrations. The unusual mineralogy of this deposit, compared with that of commonly studied base-metal and gold deposits, results in several unique geochemical characteristics. The dissolution of fluorite releases F into the pore water; the F forms strong complexes with Al and enhances the dissolution of aluminosilicate minerals within the oxidation zone. As a result, high Al concentrations (up to 151.7 mg/L) are detected in the near-neutral pore water in the oxidation zone. The combined dissolution of aluminosilicates and carbonate minerals maintains the pH near 10 in the pore water at depth. Elevated concentrations of W (up to 7.1 mg/L) are detected in the pore water throughout the tailings, likely as a result of the dissolution of wolframite. Consistent with geochemical model calculations, results from SEM/EDS, EMP/WDS and TEM/EDS analyses indicate that secondary minerals, which occur as orange-brown coatings on grains of primary-minerals, are Fe oxyhydroxides. Examples of these secondary minerals display a fibrous habit at high resolution in the TEM. One of these minerals, which contains substantial amounts of Al, As, and Si as impurities, was identified by selected-area electron diffraction (SAED) analyses to be goethite. Another mineral contains relatively high amounts of Si, Pb, Bi, and As, and SAED analyses suggest that the mineral is two-line ferrihydrite.     

云南沧源拱丁金矿床矿石物质组成及金的赋存状态

拱丁金矿床属石英脉型。通过背散射扫描电镜、电子探针及等离子光谱等方法的研究,查明其载金矿物主要为黄铁矿、毒砂、方铅矿、闪锌矿等疏化物,其中细粒-微粒自然金是Au的主要存在形式。文中首次报道了锌-银金矿变种在自然界的存在,并对金的成矿机理做了一定讨论。     

Applied Mineralogical Studies on Iranian Titanium Deposits

Qara-aghaj and Skandian as hard rock titanium deposit and Kahnooj one as a placer deposit were investigated from applied mineralogical point of view. The mineralogical studies were carried out using XRD, XRF, optical microscopy, scanning electron microscopy and microprobe analysis. These studies indicated that ilmenite and magnetite are main valuable minerals in the studied ores. Pyroxene, olivine and plagioclase are the main gangue minerals in Qara-aghaj ore while chlorite and plagioclase are the major gangue minerals in Skandian ore. Plagioclase, clinopyroxene, amphibole, feldspate and some quartz are the important gangue minerals in kahnooj deposit. In all three ores ilmenite is mainly in the form of ilmenite grains but some lamellae of ilmenite with thickness between 0.1 to 20 μm have been occurred as exsolution textures inside magnetite grains, where the magnetite here can be referred to as ilmenomagnetite. In the hard rock ores some fine ilmenites have been disseminated in silicate minerals. The liberation degree of granular ilmenite was determined 150, 140 and 200 μm for Qara-aghaj, Skandian and Kahnooj, respectively. So, only the granular form of ilmenite is recoverable by physical methods. Some sphene and rutile as titanium containing minerals were observed mainly inside ilmenite phase in kahnooj ore. Some fine rutile was also found inside Skandian ilmenite while there were not any other titanium minerals inside Qara-aghaj ilmenite. Apatite is another valuable mineral which was found only in Qara-aghaj ore. Using SEM and microprobe analysis it was found that there are different amounts of exsolved fine lamellae of hematite inside ilmenite in Qara-aghaj and Kahnooj ores while it was not observed in Sckandian one. The average contents of TiO2 in the lattice of Qara-aghaj, Skandian and Kahnooj ilmenite were determined 51.13, 50.9% and 52.02%, respectively. FeO content of ilmenite lattice for all three samples is clearly lower than the theoretical content. This is due to the substitution of Mg and Mn for some Fe2+ ions in the ilmenite lattice. V2O3 content of magnetite lattice is up to 1%. So, magnetite can be a suitable source for production of vanadium as a by-product in all three deposits.     

Platinum and palladium mobility in supergene environment: The residual origin of the Pirogues River mineralization, New Caledonia

Eluvial concentration of platinum-group minerals (PGM) has developed in the south of New Caledonia, from the weathering of a mafic and ultramafic cumulate. The platinum/palladium (Pt/Pd) ratio evolution from the bottom to the top of the weathering profile indicates a chemical mobilization of Pd in supergene environment. The examination by scanning electron microscopy of the residual PGM collected in the weathering profile and their chemical characterization by electronic microprobe show a preservation of the structure and chemical signature (in the core of the grains) of the fresh PGM. This clearly demonstrates that the PGM studied here are residual and are affected by dissolution process.     

云阳微结晶石英岩矿成因探讨

通过化学分析、X-射线衍射、红外光谱、扫描电镜和电子探针等方法,研究了云阳粉石英矿的成分和结构.根据氧同位素、包裹体测温以及周围岩石特征,讨论了微结晶石英岩的硅质来源和成因.认为云阳粉石英矿具有热水成因的特点,热水来源于地下热水,硅质来源于热水对含硅地层中含硅矿物的溶浸与萃取,形成富含硅的热水,交代碳酸盐岩形成微结晶石英岩.地形地貌、地质环境和矿石结构等条件是影响微结晶石英岩风化形成粉石英矿的主要因素.     

Iron–bentonite interactions in the Kawasaki bentonite deposit,Zao area,Japan

Greenish veins occurring in brecciated bentonite were found in the Kawasaki bentonite deposit of the Zao region in Miyagi Prefecture, Japan. Their occurrence possibly indicates the interaction of bentonite with Fe-rich hydrothermal solutions. In order to prove the hypothesis and understand the long-term mineralogical and petrographic evolution of bentonite during such interactions, the greenish veins and the surrounding altered bentonite were analyzed using X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe micro-analysis (EPMA), scanning transmission electron microscopy with energy dispersed spectroscopy (STEM-EDS) and micro X-ray absorption near-edge structure (XANES). The greenish veins resulting from hydrothermal solution are composed of mixed-layer minerals consisting of smectite and glauconite (glaucony), pyrite and opal. The occurrences indicate that glaucony and pyrite formed almost simultaneously from hydrothermal solution prior to opal precipitation. The mineral assemblages of the greenish veins and their surroundings indicate that the hydrothermal activity had most likely taken place at a temperature of less than 100 °C and that the pH and Eh conditions of the reacted solution were neutral to alkaline pH and reducing. The unaltered bentonite is composed mainly of Al smectite and opal. These minerals coexist as a mixture within the resolution level of the microprobe analyses. On the other hand, the bentonite in contact with the greenish veins consists of discrete opal grains and dioctahedral Al smectite containing Fe and was altered mineralogically and petrographically by the hydrothermal activity. Both the clay minerals and the opal were formed by dissolution and subsequent precipitation from the interaction of the original bentonite with the hydrothermal solution.     

地幔橄榄石流体包裹体中的微量元素

本文基于激光探针二次离子质谱对地幔橄榄石中单个CO_2流体包裹体的爆破分析,以及中子活化、超高压透射电镜分析结果,讨论微量不相容元素存在状态对地幔地球化学演化的影响。     

随州陨石不透明矿物研究

随州陨石不透明矿物有陨硫铁、铁纹石、镍纹石、自然铜、含镍黄铜矿、洛铁矿、钛铁矿等。本文对它们进行了反光显微镜鉴定、X射线分析、反射率及硬度的测定和电子探针分析，总结了不同化学群的球粒陨石铬铁矿、钛铁矿中FeO、MgO含量变化规律。