层状硅酸盐矿物填料在聚合物中的应用及发展

高岭土、云母、滑石三种常见的层状硅酸盐矿物在聚合物中作为填料对聚合物的刚性，尺寸稳定性及其它物理化学性能如抗压，抗冲击，耐腐蚀，绝缘性有显著的影响。滑石粉可以提高填充材料的刚度冲击强度，硬度和降低线膨胀系数等；高岭土可增大材料的体积，提高塑料的绝缘强度，电阻，增强对红外线阻隔效果等；白云母有利于提高聚丙烯的刚性和屈服强度，冲击强度和断裂伸长率等。聚合物／层状矿物纳米材料的制备作为新兴的技术有着广阔的应用前景。     

A Quaternary Solution Model for White Micas Based on Natural Coexisting Phengite-Paragonite Pairs

A thermodynamic model for the quaternary white mica solid solutionwith end-members muscovite–Mg-celadonite–paragonite–Fe-celadonite(Ms–MgCel–Pg–FeCel) is presented. The interactionenergies for the MgCel–Pg join, the FeCel–Pg joinand the ternary interactions were obtained from natural coexistingphengite–paragonite pairs. Phengite–paragonite pairswere selected based on the criteria that their chemical compositionsmay be represented as a linear combination of the model end-membercompositions and that the respective formation conditions (350–650°C,4–21 kbar) are accurately known. Previously publishedexcess free energy expressions were used for the Ms–Pg,Ms–MgCel and Ms–FeCel binaries. The suggested mixingmodel was tested by calculating multicomponent equilibrium phasediagrams. This proved to be particularly well suited to reproducecompositional variations of white micas from amphibolite-faciesmetapelites. KEY WORDS: white mica; solution model; equilibrium phase diagrams     

Phase Relations and Chemical Composition of Phengite and Paragonite in Pelitic Schists During Decompression: a Case Study from the Monte Rosa Nappe and Camughera-Moncucco Unit, Western Alps

The metamorphic evolution of metapelites from the eastern partof the Monte Rosa nappe and the Camughera–Moncucco unit,both situated in the upper Penninic units SW of the Simplonline, were investigated using microstructural relationshipsand equilibrium phase diagrams. The units under considerationexperienced pre-Alpine amphibolite-facies conditions and underwenta complex metamorphic evolution during the Alpine orogeny. Peakpressures during an early Alpine high-pressure stage of 12·5–16kbar were similar in the Monte Rosa nappe and Camughera–Moncuccounit. A pronounced thermal gradient is indicated during decompressionleading to an amphibolite-facies overprint, as the decompressionpaths went through the chlorite, biotite and plagioclase stabilityfields in most of the Monte Rosa nappe, through the staurolitefield in the easternmost Monte Rosa nappe and in the Camughera–Moncuccounit, and through the sillimanite field in the easternmost Camughera–Moncuccounit. In high-Al metapelites the initial formation of stauroliteis related to continuous paragonite breakdown and associatedformation of biotite. In the course of this reaction phengitebecomes successively sodium enriched. In low-Al metapelites,in contrast, the initial staurolite formation occurs via thecontinuous breakdown of sodium-rich phengite. In both low- andhigh-Al metapelites the largest volume of staurolite is formedduring the continuous breakdown of sodium-rich phengite belowP–T conditions of about 9·5 kbar at 600–650°C.During this reaction phengite becomes successively potassiumenriched as sodium from phengite is used to form the albitecomponent in plagioclase. For ‘normal’ pelitic chemistries,phengite becomes Na enriched during decompression through thebreakdown of paragonite along a near-isothermal decompressionpath. The Na content in phengite reaches its maximum when paragoniteis entirely consumed. During further decompression the paragonitecomponent in phengite decreases again because Na is preferentiallyincorporated into the albite component of plagioclase. KEY WORDS: metapelites; white mica; high pressure; equilibrium diagrams; Western Alps     

粤西小片云母资源及其开发利用

粤西有着丰富的小片云母资源，其开发利用对广东的经济发展有着十分重要的意义。本文介绍了粤西小片云资源概况，并论述了开发利用途径和前景最后，对粤西小片云母资源的开发利用提出了建议。     

Microstructural evidence of rotation and non-rotation of mica porphyroblasts

Abstract Mica porphyroblasts in schists from several regions show nearly planar inclusion trails that are parallel over areas much larger than the wavelengths of later folds. This indicates that the porphyroblasts have not rotated, with respect to geographical co-ordinates, during deformation. Instead, the matrix has rotated, as suggested by Ramsay (1962). Even in zones of marked shortening in the matrix adjacent to large rigid porphyroblasts (e.g. of cordierite or staurolite), small biotite porphyroblasts have not rotated, but have become thinned by solution, as indicated by parallelism of inclusion trails in separate biotite grains and by evidence of truncation of inclusion trails by the matrix foliation. Less common are biotite porphyroblasts that have single asymmetrical microfolds in the matrix adjacent to the porphyroblasts and so appear to have rotated; these porphyroblasts are characterized by kinking.     

Quantification of electron microprobe compositional maps of rock thin sections: an optimized method and examples

Quantification of discrete pressure–temperature domains in deformed chlorite + white mica‐bearing metapelites was undertaken on mineral compositions derived by two‐dimensional microprobe compositional mapping of selected areas of rock thin sections. In order to achieve compositional information at sufficient analytical precision, spatial resolution and sample coverage within a typical analysis time of 1 day, an optimization of measurement methods was necessary. The method presented here allows collection of raw counts for eight different element concentrations at an analytical precision of ～1–2 wt%. X‐ray intensity multiplane maps (one map per measured chemical element) are translated into concentration multiplane maps, utilizing selected conventionally measured spot analyses combined with the Castaing approximation for each mineral. As this step requires identification of the different minerals present in the mapped area, a statistical clustering technique to identify different groups of composition was developed, guided by simple petrographic inspection of the thin section, to delineate the important minerals in the mapped area. Finally, the compositions of each pixel are translated into a mineral structural formula thus yielding a new kind of image with a high content of petrological information. The reliability of the mineral composition images was emphasized by carrying out precision tests on the analytical data. The possible use of chemical maps to infer the P–T–deformation history of metamorphic rocks is illustrated with two samples from the Spitzbergen and the Sambagawa blueschist facies belts. In both samples, a strong correlation between structures and chemistry is observed. Qualitative estimates of P–T conditions from the Si‐content of mica and chlorite are in good agreement with their location in microstructures that formed at different times. Therefore, the combination of chemical maps with microstructural observations is a very powerful approach to understand both the evolution of complex metamorphic rocks and the control by deformation of mineral reactivity.     

Low- and high-alumina komatiites of Goiás, Central Brazil

Archean komatiites of Goiás, central Brazil, have experienced deformation and low-grade metamorphism, but several outcrops preserve primary volcanic features. Samples from less deformed komatiites of four out of five greenstone belts (Crixás, Guarinos, Pilar de Goiás, and Santa Rita) have been investigated for their geochemical properties. Komatiites from the Crixás greenstone belt have very low Al₂O₃/TiO₂, high CaO/Al₂O₃, and a hump-shaped rare earth element (REE) pattern. Those from the Guarinos and Pilar de Goiás belts have similar REE patterns, characterized by a slight enrichment in LREE coupled with almost flat HREE, but differ in their inter-incompatible element ratios. Compared with those from Pilar de Goiás and Guarinos, samples from the Santa Rita belt have fractionated REE patterns with LREE enrichment, as well as high Al₂O₃ contents, corresponding to Al-undepleted komatiites. Komatiites from Crixás have the lowest (La/Sm)_N, (La/Yb)_N, and Zr/Zr* ratios compared with their equivalents from the other belts, which suggests their source was relatively depleted in LREE and high field strength elements (HFSE), probably due to the retention of garnet in the residue. Komatiites from the Guarinos, Pilar de Goiás, and Santa Rita greenstone belts are enriched in incompatible elements, which can be attributed to either low-degree partial melting at high pressures or a source previously enriched in incompatible elements. Some of the studied komatiites belong to Al- and HREE-depleted and others to the Al- and HREE-undepleted types. The depleted komatiites probably derived by melting at depths greater than 200 km, the undepleted at less than 200 km. Therefore, the komatiites of the four belts may have been derived from either one single mantle plume with different melting depths or sources from distinct plumes.     

湘南香花岭锡铅锌多金属矿田的云母类型及对成矿的指示

湘南癞子岭花岗质复式岩体是香花岭锡铅锌多金属矿田的主要成矿岩体,其中云母广泛出现在各期次岩（矿）体之中。笔者等在对癞子岭岩体岩相学研究的基础上,开展全岩主微量元素地球化学分析,同时对岩浆成因云母（花岗岩中的云母）、热液成因云母（矿化云英岩、晶洞矿物集合体以及条纹岩中的云母）进行了电子探针分析。结果表明,癞子岭岩体为一套高钾钙碱性—钾玄质、准铝质—过铝质花岗岩,癞子岭岩体中的云母主要为铁锂云母,从早期到晚期,呈现出FeO和Al2O3含量降低,K2O、F、MnO和Rb2O含量升高,且Pb、Zn、Fe等成矿元素含量逐渐增加的特征。热液成因云母分为以下两种： ① 产于矿化云英岩和晶洞矿物集合体中的云母主要形成于流体出溶的早期,无围岩组分参与,云母类型由铁锂云母演化为锂云母,主要沉淀Fe、Zn、Pb、Mo等成矿元素;② 产于条纹岩中的云母晚于矿化云英岩和晶洞矿物集合体中的云母,有围岩组分参与,云母类型由黑鳞云母变为富镁黑云母和富铁黑云母再变为金云母,主要沉淀Fe、Sn和W等成矿元素。随着流体演化,云母呈现SiO2、F、K2O含量逐渐降低,MgO含量逐渐升高,相应的成矿元素从富Fe 、Zn、Pb、Mo逐渐过渡到富Fe 、Sn和W。     

Chemical Features of White Micas from the Piemonte Calc-schists, Western Alps and Implications for K–Ar Ages of Metamorphism

Anomalously large chemical ranges in muscovite-paragonite and muscovite-celadonite systems are observed in white micas from the Piemonte calcschists in the Chisone valley area, internal western Alps. The petrographical and chemical observations on white mica strongly suggest that most mica crystals with high Na/K ratios in the chlorite zone are of detrital origin, and were derived from the pre-Alpine high-temperature metamorphic sequence such the Caledonian and/or Variscan. Submicroscopic muscovite (Ms) - paragonite (Pg) composite aggregates occur in the chlorite zone and their EPMA analyses give an apparent chemical composition range from Ms_0.6Pg_0.4 to Ms_0.2Pg_0.8. In the rutile zone, the paragonite content of the white micas is less than 20%, suggesting that the white micas have been homogenized during the Alpine metamorphism even if detrital white micas existed.Metamorphic mica is also very heterogeneous. The total range in Si content becomes wider with increasing of metamorphic grade: 3.22–3.39 pfu for the chlorite zone, 3.07–3.45 pfu for the chloritoid zone and 3.06–3.59 pfu for the rutile zone. This clearly indicates that the micas have experienced significant retrogressive chemical reactions during cooling and exhumations of the host schists.The detrital white mica in the chlorite zone has not reset well in its K-Ar system during the Alpine subduction-related metamorphism. The wide range of the white mica K-Ar ages from 115 to 41 Ma must be due to a mixture of various amounts of detrital white mica in the separates. This feature is also observed in the chloritoid zone though the age variation is not so large as that in the chlorite zone. In contrast, the mica in the rutile zone, which was higher than 450°C, has been reset completely during Alpine HP metamorphism.     

云母的命名

定义云母为层状硅酸盐。其结构单元由两个相向排列的四面体片（Ｔｓ）和夹于其间的一个八面体片（Ｏｓ）组成。这些片构成一个单元层,层与层之间被非水化层间阳离子（Ｉ）分开,其顺序是：非水化阳离子层、四面体片、八面体片、四面体片、非水化阳离子层、四面体片、八面...