X射线粉晶衍射仪在山东蒙阴金伯利岩蚀变矿物鉴定中的应用   总被引：5，自引：4，他引：1  

迟广成  宋丽华  王娜  崔德松  周国兴 《岩矿测试》2010,29(4):475-477

山东蒙阴金伯利岩组成矿物以蚀变矿物为主,X射线粉晶衍射仪鉴定结果显示无矿金伯利岩矿物组分为方解石、白云石、石英、钙锆钛矿,标志性矿物为白云石和钙锆钛矿;贫矿金伯利岩矿物组分为蛇纹石、方解石、钙铝榴石、磁铁矿和金云母,标志性矿物为钙铝榴石;富矿金伯利岩矿物组分为蛇纹石、方解石、绿泥石、磷灰石、磁铁矿和金云母,标志性矿物为绿泥石和磷灰石。采用X射线粉晶衍射仪鉴定金伯利岩蚀变矿物组合,寻找蚀变矿物组分变化与金伯利岩含矿性的关系,利用标志性的蚀变矿物判断金伯利岩无矿、贫矿还是富矿,是非常有意义的。  相似文献   

水体悬浮颗粒物的扫描电镜与X射线能谱显微分析   总被引：3，自引：0，他引：3  

盛东  胡忻  刘锡尧 《岩矿测试》2010,29(6):683-686

通过对湖州地区74个土壤样品多环芳烃含量的测定,分析了湖州市不同土地利用类型土壤中多环芳烃(PAHs)的含量特征及污染水平。结果表明,湖州地区PAHs各组分的含量均有检出,各种土地利用类型表层土壤均受到一定程度的PAHs污染,但均小于荷兰土壤修复标准;湖州市区耕地中PAHs的含量最高;从PAHs低环/高环比值小于1以及芘/苯并(a)芘比值小于2,反映了湖州地区土壤中PAHs主要是由燃煤和生活污染产生的。  相似文献   

Simulations and Mitigation of Pile-Up in XMM CCD Instruments     

D. H. Lumb 《Experimental Astronomy》2000,10(4):439-456

Simulations of the XMM EPIC instruments are presented. They suggest the correct operating mode must be chosen to ensure that spectral analysis of the data is not compromised by pile-up effects. The performanceis contrasted with the CHANDRA AXAF CCD Imaging Spectrometer, showing how the higher effective area but better over-sampling of its mirror response function in XMM, impacts this pile-up criteria. Targetsexceeding a flux of a few 10^-12 ergs cm^-2 s^-1 will becompromised for spectral analysis in these CCD instruments, unlesscare is taken in defining correct instrument configurations. Somesimple methods of mitigating the effects are described, but this featureof X-ray pile-up warrants careful attention in calibration.  相似文献   

Direct evidence of transformation from smectite to palygorskite: TEM investigation   总被引：3，自引：0，他引：3  

CHEN Tianhu  XU Huifang  LU Anhuai  XU Xiaochun  PENG Shuchuan &YUE Shucang .College of Resources  Environmental Engineering  Hefei University of Technology  Hefei  China  .Department of Geology  Geophysics  University of Wisconsin  Madison  WI  USA  .Department of Geology  Peking University  Beijing  China Correspondence should be addressed to Chen Tianhu 《中国科学D辑(英文版)》2004,47(11):985-994

Palygorskiteusuallyisonlyaminorcomponentofmodernsedimentsandsoils.Onlyinspecificenvi-ronmentscanitoccurinlargeamountsandformeco-nomicaldeposits.Inspiteofitsscarcity,thismineralhasbeenrecordedinnumerousenvironments,rangingfromdeepseaandperitidalflatstosoilsandlacustrinesedimentaryrock[1—4].Palygorskiteinsedimentaryrocksandsoilscanbeofthreedifferentorigins:inherited,detritalandauthigenic[5].Theformationmechanismsofauthigenicpalygorskitearestillcontroversial,andvariousproc-esseshavebeenproposedf…  相似文献   

Comparative compressibility and equation of state of orthorhombic and tetragonal edingtonite     

G. D.?GattaEmail author  T. Boffa?Ballaran  P.?Comodi  P. F.?Zanazzi 《Physics and Chemistry of Minerals》2004,31(5):288-298

The high-pressure (HP) behaviour of a natural orthorhombic and tetragonal edingtonite from Ice River, Canada, has been investigated using in situ single-crystal X-ray diffraction. The two isothermal equations of state up to 6.74(5) GPa were determined. V₀, K_T0 and K refined with a third-order Birch–Murnaghan equation of state (BM-EoS) are: V₀ = 598.70(7) ų, K_T0 = 59(1) GPa and K=3.9(4) for orthorhombic edingtonite and V₀ = 600.9(2) ų, K_T0 = 59(1) GPa and K=4.2(5) for tetragonal edingtonite. The experiments were conducted with nominally hydrous pressure penetrating transmitting medium. No overhydration effect was observed within the pressure range investigated. At high-pressures the main deformation mechanism is represented by cooperative rotation of the secondary building unit (SBU).Si/Al distribution slightly influences the elastic behaviour of the tetrahedral framework: the SBU bulk moduli are 125(8) GPa and 111(4) GPa for orthorhombic and tetragonal edingtonite, respectively. Extra-framework contents of both zeolites show an interesting behaviour under HP conditions: the split Ba2 site at P >2.85 GPa is completely empty; only the position Ba1 is occupied. Electronic Supplementary Material. Supplementary material to this paper (Observed and calculated structure factors) is available in electronic form at Electronic Supplementary Material Supplementary material is available in the online version of this article at  相似文献   

Tilting and distortion of CaSnO<Subscript>3</Subscript> perovskite to 7 GPa determined from single-crystal X-ray diffraction     

J.?Zhao  N. L.?RossEmail author  R. J.?Angel 《Physics and Chemistry of Minerals》2004,31(5):299-305

The structural changes of CaSnO₃, a GdFeO₃-type perovskite, have been investigated to 7 GPa in a diamond-anvil cell at room temperature using single-crystal X-ray diffraction. Significant changes are observed in both the octahedral Sn–O bond lengths and tilt angles between the SnO6 octahedra. The octahedral (SnO6) site shows anisotropic compression and consequently the distortion of SnO6 increases with pressure. Increased pressure also results in a decrease of both of the inter-octahedral angles, Sn–O1–Sn and Sn–O2–Sn, indicating that octahedral tilting increases with increasing pressure, chiefly equivalent to rotation of the SnO6 octahedra about the pseudocubic <001>_p axis. The distortion in the CaO12 and SnO6 sites, along with the octahedral SnO6 tilting, is attributed to the SnO6 site being less compressible than the CaO12 site.Acknowledgments The authors acknowledge with gratitude the financial support for this work from NSF grant EAR-0105864. Ruby pressure measurements were conducted with the Raman system in the Vibrational Spectroscopy Laboratory in the Department of Geosciences at Virginia Tech with the help of Mr. Charles Farley.  相似文献   

Phase transition and compression behavior of gibbsite under high-pressure     

H.?LiuEmail author  J.?Hu  J.?Xu  Z.?Liu  J.?Shu  H. K.?Mao  J.?Chen 《Physics and Chemistry of Minerals》2004,31(4):240-246

In situ high-pressure synchrotron X-ray diffraction and infrared absorption experiments for gibbsite were performed at room temperature up to 53 and 25 GPa, respectively. A phase transition was confirmed at about 2.5 GPa. The high-pressure phase is indexed as an orthorhombic structure, rather than a triclinic structure as reported in previous studies. The compressibility of gibbsite and its high-pressure polymorph were studied, and their bulk moduli K₀ were determined to be 49 and 75 GPa, respectively with K₀ as 4. The in situ high-pressure infrared absorption spectra revealed the gradual disordering of hydrogen substructure above 15 GPa in quasihydrostatic compression.  相似文献   

Single-crystal X-ray diffraction study of cation distribution in MgAl<Subscript>2</Subscript>O<Subscript>4</Subscript>–MgFe<Subscript>2</Subscript>O<Subscript>4</Subscript> spinel solid solution     

A.?NakatsukaEmail author  H.?Ueno  N.?Nakayama  T.?Mizota  H.?Maekawa 《Physics and Chemistry of Minerals》2004,31(5):278-287

Synthesis experiments in the system MgAl₂O₄–MgFe₂O₄ [MgAl_2–xFe_xO₄ (0 x 2)] were carried out using a PbF₂ flux. The crystalline products synthesized in the compositional range of 0.6 <x 1.2 consisted of two spinel phases, whereas those synthesized in the compositional ranges of 0.0 x 0.6 and 1.2 < x 2.0 crystallized as single spinel phases. Structure refinements of the spinel single crystals, which grew in the ranges of 0.0 x 0.6 and 1.2 < x 2.0, show that the degree of randomness of cation distribution between A and B sites increases as x approaches the two-phase region. This means that the degree of the size mismatch among Mg²⁺, Fe³⁺ and Al³⁺occupying each equivalent mixing site increases as x approaches the two-phase region. Consequently, if the coexistence of two spinels observed in the intermediate compositions reveals the existence of a miscibility gap at low temperatures, this increase in the degree of the size mismatch among the three cations is suggested as a factor of energetic destabilization to form the miscibility gap.  相似文献   

Rigid unit modes at high pressure: an explorative study of a fibrous zeolite-like framework with EDI topology     

G. D.?GattaEmail author  S. A.?Wells 《Physics and Chemistry of Minerals》2004,31(8):465-474

We report a comparative study on the high pressure (HP) structural behaviour of a fibrous zeolite (with EDI topology) on the basis of rigid unit modes (RUM) modelling and previously published single-crystal X-ray diffraction. HP single-crystal diffraction data lead to a more precise determination of the elastic parameters (axial and volume compressibilities) useful to define the equation-of-state under isothermal conditions, and the structural refinements are useful to describe the main deformation mechanisms of the Si/Al framework and extra-framework content at high pressure. The RUM modelling is applied to simulate the compressive behaviour of the framework, under hydrostatic and non-hydrostatic conditions, using a minimum number of parameters, and to describe the deformation mechanism intuitively in terms of the rotations of the SiO₄ polyhedra. The local and global P-induced deformation mechanisms of the Si/Al framework observed in experiment (channel ellipticity, SBU rotation) are well reproduced by RUM modelling. The simulation of uniaxial compression (non-hydrostatic conditions) shows an interesting result on the structural behaviour. This comparative study tests the reliability of the RUM modelling in open-framework silicates with a complicated crystal structure.Electronic Supplementary Material: Supplementary material to this paper is available in electronic form at  相似文献   

Conversion of carbonaceous material to graphite within the Greywacke Zone of the Eastern Alps   总被引：1，自引：0，他引：1  

Gerd?RantitschEmail author  Werner?Grogger  Christian?Teichert  Fritz?Ebner  Christian?Hofer  Eva-Maria?Maurer  Bernhard?Schaffer  Michael?Toth 《International Journal of Earth Sciences》2004,93(6):959-973

Morphology and reflectance of carbonaceous material (CM) in Late Carboniferous metasediments of the eastern Greywacke Zone (Eastern Alps) indicate a mixture of vitrinite, grainy textured and lamellar shaped particles. As imaged by high-resolution atomic-force microscopy, vitrinite and the grainy textured particles show mesophase structures which can be described as facetted nanocrystals within the carbon matrix. High-resolution transmission electron microscopy has revealed two types of microtextures representing different degrees of graphitization. The first type is characterized by elongated ring-shaped microtextures, whereas the second type is characterized by graphite lamellae and polygonal flakes with long-range ordered aromatic layers. In spite of the heterogeneity of the CMs, the geographical distribution of quantitative metamorphic parameter (Raman spectra parameter, X-ray diffraction pattern, microscopic reflectance) suggests a graphitization process which is promoted by advective heat transport during post-collisional processes. In a tentative pressure-time path, Late Cretaceous thrusting results in a turbostratic ordering of the aromatic layer. Ordering to long-range ordered aromatic layers was achieved during the Late Cretaceous-Paleogene exhumation of mid-crustal rocks beneath the eastern Greywacke Zone.  相似文献