测量晶体光率体与结晶方位的二轴针台

二轴针台由一个东西轴和针轴(相当于南北轴)构成,加上显微镜的载物台(直立轴)实际上是一个三度空间可旋转的针台。二轴针台的南北轴可以任意旋转360°,空间中的任一条直线经过南北轴的旋转可以水平,任意面可以直立。转动东西轴和南北轴可以使空间中87％~1)的直线直立。四轴或五轴弗氏台不能直立或水平的面和线,在两轴针台上可以使其直立或水平。二轴针台采用分别直立二个光轴的办法来研究二轴晶的光率体方位。二轴针台还可以使晶体中所能见到的晶面或解理面直立,并且在赤平投影网上研究晶体光率体与结晶方位的关系。     

矿物包裹体特征对古岩溶作用的指示性

碳酸盐岩溶蚀孔缝中充填矿物包裹体特征对古岩溶作用环境和期次具有较好的指示性.黄骅坳陷奥陶系充填矿物包裹体物理特征反映古岩溶作用环境为埋藏型,包裹体化学特征显示了古岩溶作用与有机质熟化程度有关.包裹体各项特征指标的明显差异性与古岩溶作用的多期性相对应:3种盐度类型反映了浅埋藏、中等埋藏和深埋藏3种环境;4个均一温度段与古岩溶发育的4个期次相吻合.     

一种直接测定2V和光率体定位的多用三轴针台

矿物的2V和主折射率是矿物学资料的基本数据之一,是鉴定透明矿物很重要的依据;文契尔半圆柱鉴定系统亦以这几个常数编制。在测定透明矿物的2V和折射率的工作中,旋转针台受到越来越普遍的重视,它已逐渐成为光性矿物学工作中的基本工具之一。 用一轴针台可以较准确地测定2V,同时因为可以对晶体的光率体作准确的定位,测定主折射率的精度也超过一般的方法。但是,一轴针台锥光法测2V一般误差较大;消光     

介绍一种成因指示矿物—硅铁矿

硅铁矿根据晶系的不同可分为等轴硅铁矿和正方硅铁矿。两种矿物常紧密地孪生在一起。等轴硅铁矿呈锡白色;正方硅铁矿为钢灰色。它们均具金属光泽、贝壳状断口、无解理、不透明。摩氏硬度、比重、反射率分别为6.5、6.25、6.18、5.05、39％、36％。呈细粒状晶体(0.1—3毫米)或仅见晶形轮廓的树枝状、锯齿状出现。其化学成分见表1,分析值符合于Fe_2Si_3。     

应用光率体论述宝石折射率仪测试原理及其应用

】应用晶体光学中的光率体原理对宝石折射仪测试应用问题作较为详尽的论述,特别对一轴晶、二轴晶宝石测试所遇到的各种现象作进一步全面探讨,并给予确切的解释。     

云南永胜县光茅山斑岩体含矿性探讨

通过对光茅山1#、4#、9#、6#斑岩体岩石化学特征分析研究,以及与马厂箐斑岩型铜矿和扬子地台西缘含铜(钼)矿富碱斑岩的对比,认为光茅山斑岩体具一定的含矿性,具有较好的找矿前景。     

在岩石薄片中直接测定透明矿物折射率的一种新方法

从透射系数转换成折射率的方法,明显地提高了岩石薄片的价值,从而缩减其它一些测试过程.若和现有的许多成分—光性图表结合,可以较快地解决类质同像矿物的区分,对不同工艺特征、不同工业品级、不同含矿性的同一标型矿物,都能提供直接的对比资料,因此具有较高的实用价值.     

内陆盐湖石盐流体包裹体均—温度指示意义的现代过程研究

Halite precipitation with water and air temperature was observed in detail, and homogenization temperature of fluid inclusions in halite formed in ancient and modem Chaka Salt Lake was studied. Halite precipitates mainly in August every year and largely precipitates between 13 and 15pm at one day when water temperatures reach 20℃ but can seldom reach 30℃. Homogenization temperatures of fluid inclusions in halite formed in Chaka Salt Lake range from 14℃ to 38℃ with an average of 23.7℃. The number of inclusions appears an obvious peak value at homogenization temperatures between 18 - 25℃, which probably represent the water temperature in which halite mainly precipitates when water temperatures reach 20℃. Therefore, homogenization temperatures of fluid inclusions in halite formed in Chaka Salt Lake can wall reflect the water temperature.     

津巴布韦金刚石中石墨包裹体及金刚石异常双折射特征分析

津巴布韦马朗(Marange)金刚石矿以产出混合习性(八面体与近立方体)金刚石为特征,其石墨包裹体仅存在于近立方体区.石墨包裹体的形态、分布及金刚石的异常双折射与应变特征,能反映其从开始结晶到被搬运至地表过程中经历的地质作用.因此,对津巴布韦混合习性金刚石及石墨包裹体的研究不仅能提供与其他产地金刚石有对比意义的数据,且...     

夕卡岩中石榴石的双折射性之研究

本文研究了河北省涉县符山铁矿夕卡岩中石榴石的双折射性。该石榴石属钙铝-钙铁榴石系列,有较强的双折射性,重折率最大值约为0.009。加热可使双折射性减弱甚至消失。依形成温度,可将石榴石分为两群,重折射率相差一、两个数量级,形成温度较低者其双折射性强。在每一群中,重折率与分子式中八面体位置 Al 含量成上弯曲线关系,最强双折射大致在 And₆₅ Gro₃₅成分处。X 光单晶衍射照相出现异常,衍射点变成由数个点组成的拉长的线,这些点沿一定方向排列,强度和数目有变化,可能是因为结构中八面体位置上 Fe³⁺/Al 有序引起的。有序引起石榴石对称性降低,变为二轴晶,可以较好地解释石榴石双折射性的成因及其变化规律。本文还讨论了环带与双折射性的关系。     

光释光测年系统中绿光新光源的研制

绿光激发光源是光释光测年系统中的核心设备之一。Ar离子激光光源已不能满足为开展不同种类的矿物的光释光性质、特征等方面的研究需要。我们通过对高强度冷光卤素灯，经过一定的光学改造后获得了新的激发光源，可以代替代原有的Ar离子激光光源。     

Crystal fractionation in the friction melts of seismic faults (Alpine Fault, New Zealand)

Compositional variations are documented in friction melts along the Hari Hari section of the Alpine Fault, New Zealand, with multiple stages of melt injection into quartzo-feldspathic schists. Intermediate to felsic melts were heterogeneous in composition, but all fractions show a common trend, with a tendency for the younger melt layers and glasses to be more alkali − (Na + K) and Si-enriched, while being depleted in mafic (Fe + Mg + Mn) components. These changes are attributed primarily to crystal fractionation of the melt during transport. Farther traveled molten layers were on the whole less viscous, mostly due to a higher melt-to-clast ratio; however, compositional change, together with a decrease in volatile content, produced a progressively more viscous liquid melt with time. The glass phase is interpreted as a remnant of this high viscosity felsic residual melt that was preserved during final quenching. Following initial failure, the formation of largely phyllosilicate-derived, volatile-rich, lower viscosity melt corresponds with a phase of fault weakening. Subsequent rapid crystal fractionation during melt transport, the loss of volatiles and freezing of residual melt contributed to the strengthening of the fault during seismic slip.     

矿物光率体主轴-晶轴-弹性张量的数学转换和计算机实现的方法

以往是通过手工转图由光率体主轴获取晶轴和应力主轴的,把手工操作变为计算机运算和成图,是一个重要的附加课题．主要介绍了计算机实现轴与轴以及坐标系和投影面之间的各种转换方法,具体步骤有：（１）把费氏台下读数转换为地理坐标系下的数据;（２）已知任意两个光率体主轴求第三个光率体主轴;（３）投影面的旋转;（４）由光率体主轴获取晶轴;（５）把弹性张量从与晶轴相关的坐标系转到地理坐标系中．由此编制的处理程序和绘图软件已在应用中．     

The Effect of Additives on Crystal Size of Sodium Sulphate

正1 Introduction Anhydrous sodium,mainly produced in the United States,Canada,Japan,is indispensable commodities and raw materials in daily life and industry.In recent years,anhydrous sodium sulfate of general size was much oversupplied[1].However particles anhydrous sodium sulphate of large size is not adequate to the demand for its     

Optical processing of structural contour maps

Optical processing is a fast, easy, economical, and reliable method of quantifying map patterns. A reduced transparency of a zebra-like pattern, obtained by blackening in alternate contour bands of a map, is used as input to an optical system of a laser source and objective lens to produce Fourier transforms. By sampling the intensity distribution across the transform, information about the spatial frequency (periodicity) and orientation in the original map can be inferred. Parameters used for comparing the map images are the values of intensity distribution in the transform. These intensities are normalized and subjected to comparison using various similarity methods. Cross-multiplication of the intensities is suggested as a measure of vectorial comparison of the orientations. By plotting the directional intensities into a polar coordinate system, rose diagrams are prepared for visual comparison. Optically derived parameters are independent of scale and other restrictive and limiting requirements as demanded in techniques of map analyses based on numerically derived parameters. The technique can be used in analyzing other pictorial data including aerial photographs, rock-fabric diagrams, and thin sections.     

热变煤特殊性质与其开发利用建议研究

天然焦内炭微球是煤层遭受岩浆速热变质的产物,其显微光学特征成因解析有助于深入认识煤速热碳化和热变质。采集安徽淮北石台煤矿富含炭微球的天然焦样品,利用高分辨率反射偏光显微镜和扫描电镜等实验手段,表征了天然焦中炭微球的粒度、分布、显微光学和超微组构特征,以揭示其光学各向异性的成因和热演化意义。结果显示,远离岩体天然焦中炭微球以粗粒为主,粒径10~100 μm,少数可达150 μm以上;紧邻岩体天然焦炭微球以细粒为主,粒径1~10 μm,在岩体内脉状焦内甚至低至1 μm以下。分析显示,粗粒炭微球和炭半球分别发育“十字”消光和“波状”消光,是其内部放射状一轴晶光率体在切面内投影的光学表征;细粒炭微球发育“十字−双曲线”消光,是其内部放射排布的二轴晶光率体切片投影的旋转效应。由此可见,趋近岩体,伴随着镜质体反射率增加,煤焦光率体逐渐由规则球形(光性均质体),向二轴椭球体(一轴晶)和三轴椭球体(二轴晶)转变。在该过程中,“十字”消光和“波状”消光的粗粒炭微球是煤热脱挥发分的产物,而“十字−双曲线”消光的细粒炭微球是煤热缩聚而片层化的标志。天然焦中炭微球的显微光学特征是煤层趋热碳化的结果,本质上是其光率体受热变形的光学表征,可有效评价岩浆蚀变煤焦的热变质程度。

     

Crystal structure of meteoritic schreibersites: determination of absolute structure

Minerals of the schreibersite–nickelphosphide series (Fe,Ni)₃P crystallize in the non-centrosymmetric space group . As a consequence, they can possess two different spatial arrangements of the constituting atoms within the unit cell, related by the inversion symmetry operation. Here, we present the crystal structure refinements from single crystal X-ray diffraction data for schreibersite grains from iron meteorites Acuña, Carlton, Hex River Mts. (three different crystals), Odessa (two different crystals), Sikhote Alin, and Toluca aiming for the determination of the absolute structure of the examined crystals. The crystals studied cover the composition range from ~58 mol% to ~80 mol% Fe₃P end-member. Unit-cell parameter a and volume of the unit cell V, as well as certain topological structural parameters tightly correlate with Fe₃P content. Unit-cell parameter c, on the other hand, does not show such strong correlation. Eight of the nine crystal structure refinements allowed unambiguous absolute structure assignment. The single crystal extracted from Toluca is, however, of poor quality and consequently the structure refinement did not provide as good results as the rest of the materials. Also, this crystal has only weak inversion distinguishing power to provide unequivocal absolute structure determination. Six of the eight unambiguous absolute structure determinations indicated inverted atomic arrangement compared to that reported in earlier structure refinements (here called standard). Only two grains, one taken from Odessa iron and the other from the Hex River Mts. meteorite, reveal the dominance of standard crystal structure setting.     

Crystal morphology and surface structures of orthorhombic MgSiO3 in the presence of divalent impurity ions

Many rheological and transport properties of rocks are determined by the grain boundary structures of their constituent minerals. These grain boundaries often also hold a high concentration of dopant ions. Here, as a first step towards modelling the transport and rheological behaviour of the lower mantle, we report the results of lattice static simulations on the surface structures of Fe²⁺ and Ca²⁺-doped orthorhombic MgSiO₃-perovskite. For all the surfaces we studied, the energies of the doped structures are lowered, sometimes by more than 1 J/m², with respect to the pure surfaces. From our calculated crystal morphologies, we predict that the grains become more tabular as the concentration of Fe²⁺ ions increases, while under equilibrium conditions the grains are cubic. By calculating the replacement energies of Mg²⁺ by Fe²⁺ and Ca²⁺ ions in the six outermost surface layers, we conclude that these divalent ions would tend to segregate onto the crystal surfaces. We suggest, therefore, that the grain boundary structure and rheology of MgSiO₃-perovskite dominated rocks will be strongly affected by the presence of minor elements in the lower mantle.