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1.
2.
N. G. Konopleva G. Yu. Ivanyuk Ya. A. Pakhomovsky V. N. Yakovenchuk Yu. A. Mikhailova 《Geology of Ore Deposits》2017,59(8):729-737
Data on the occurrence, morphology, anatomy, composition, and formation conditions of loparite-(Ce) in the Khibiny alkaline pluton are given. Loparite-(Ce), (Na,Ce,Sr)(Ce,Th)(Ti,Nb)2O6, resulted from metasomatic alteration and assimilation of metamorphic host rocks at the contact with foyaite as well as foyaite on the contact with foidolite. This alteration was the highest in pegmatite, and albitite developed there. A decrease in temperature resulted in enrichment of the perovskite and tausonite endmembers in loparite-(Ce) owing to a decrease in the loparite and lueshite endmembers. La and Ce sharply predominate among rare earth elements in the composition of loparite-(Ce). 相似文献
3.
New equilibrium experiments have been performed in the 20–27 kbar range to determine the upper thermal stability limit of endmember deerite, Fe
12
2+
Fe
6
3+
[Si12O40](OH)10. In this pressure range, the maximum thermal stability limit is represented by the oxygen-conserving reaction: deerite(De)=9 ferrosilite(Fs)+3 magnetite(Mag)+3 quartz(Qtz)+5 H2O(W) (1). Under the oxygen fugacities of the Ni-NiO buffer the breakdown-reduction reaction: De=12 Fs+2 Mag+5 W+1/2 O2 (10) takes place at lower temperatures (e.g. T=63° at 27 kbar). The experimental brackets can be fitted using thermodynamic data for ferrosilite, magnetite and quartz from Berman (1988) and the following 1 bar, 298 K data for deerite (per gfw): Vo=55.74 J.bar-1, So=1670 J.K-1, H
f
o
=-18334 kJ, =2.5x10-5K-1, =-0.18x10-5 bar-1. Using these data in conjunction with literature data on coesite, grunerite, minnesotaite, and greenalite, the P-T stability field of endmember deerite has been calculated for P
s=P
H
2O. This field is limited by 6 univariant oxygenconserving dehydration curves, from which three have positive dP/dT slopes, the other three negative slopes. The lower pressure end of the stability field of endmember deerite is thus located at an invariant point at 250±70°C and 10+-1.5 kbar. Deerite rich in the endmember can thus appear only in environments with geothermal gradients lower than 10°C/km and at pressures higher than about 10 kbar, which is in agreement with 4 out of 5 independent P-T estimates for known occurrences. The presence of such deerite places good constraints on minimum pressure and maximum temperature conditions. From log f
O
2-T diagrams constructed with the same data base at different pressures, it appears that endmember deerite is, at temperatures near those of its upper stability limit, stable only over a narrow range of oxygen fugacities within the magnetite field. With decreasing temperatures, deerite becomes stable towards slightly higher oxygen fugacities but reaches the hematite field only at temperatures more than 200°C lower than the upper stability limit. This practically precludes the coexistence deerite-hematite with near-endmember deerite in natural environments. 相似文献
4.
Krivovichev S. V. Yakovenchuk V. N. Panikorovskii T. L. Savchenko E. E. Pakhomovsky Ya. A. Mikhailova Yu. A. Selivanova E. A. Kadyrova G. I. Ivanyuk G. Yu. 《Doklady Earth Sciences》2019,488(2):1200-1202
Doklady Earth Sciences - Nikmelnikovite, Ca12Fe2+Fe$$_{3}^{{3 + }}$$Al3(SiO4)6(OH)20, a new mineral from the Kovdor massif (Kola Peninsula, Russia), is described. It is the first trigonal... 相似文献
5.
6.
Deerite, Fe
12
2+
Fe
6
3+
[Si12O40](OH)10, thus far known from ten localities in glaucophane schist terranes, was synthesized at water pressures of 20–25 kb and temperatures of 550–600 °C under the
of the Ni/NiO buffer. The X-ray powder diagram, lattice constants and infrared spectrum of the synthetic phase are closely similar to those of the natural mineral. A solid solution series extends from this ferri-deerite end member to some 20 mole % of a hypothetical alumino-deerite, Fe
12
2+
Al
6
3+
[Si12O40](OH)10. The upper temperature breakdown of ferri-deerite to the assemblage ferrosilite +magnetite+quartz+water occurs at about 490 °C at 15 kb, and 610 °C at 25 kb fluid pressure for the
of the Ni/NiO buffer. Extrapolation of these data to lower water pressures indicates that deerite can be a stable mineral only in very low-temperature, high-pressure environments. 相似文献
7.
Kashaev A. A. Ivanova L. A. Medvedev V. Ja. Uschapovskaya Z. F. 《Doklady Earth Sciences》2019,484(2):160-162
Doklady Earth Sciences - As a result of experimental studies on the interaction between a charoite substrate and host lamprophyres of microcline-arfvedsonitic composition, a new... 相似文献
8.
The temperature dependence of the absorption spectra of ilvaite, Ca(Fe2+,Fe3+)Fe2+Si2O8(OH), shows strongly one dimensional transport behaviour with no singularity at the Pnam-P21/a phase transition point near 335 K. Polarized single crystal transmission measurements were carried out between 300 K and
450 K in a frequency range between 600 and 23 000 cm−1. No Drude —absorption at low energies was found at any temperature. A macroscopic, thermodynamic model based on Landau-Ginzburg
theory is given which accounts for the observed macroscopic properties of the structural phase transition and its coupling
with the Fe2+-Fe3+ ordering. This ordering scheme is discussed on an atomistic level and compared with the behaviour of magnetite and trans-(CH)
x
. 相似文献
9.
K. Mereiter 《Mineralogy and Petrology》1972,18(3):185-202
Zusammenfassung Die Kristallstruktur von künstlichem Voltait, K2Fe5
2+Fe3
3+Al[SO4]12· ·18 H2O, kubisch hexakisoktaedrisch,Fd3c–O
h
8,a
0=27,254 ,Z-16, wurde mittels photographischer Röntgendaten bestimmt. Die Aufklärung der Struktur erfolgte mit Patterson- und Fouriermethoden unter Zuhilfenahme des multiplen isomorphen Ersatzes. Die Verfeinerung nach der Methode der kleinsten Quadrate ergab mit anisotropen Temperaturfaktoren für 726 beobachteteF
hkl
R=0,033. Das Hauptmerkmal der Struktur ist ein 3dimensionales Gerüst aus [Fe3+O6]-Oktaedern, [Fe
5
6/2+
Fe
1
6/3+
O4(H2O)2]-Oktaedern und [K+O12]-Polyedern, die durch SO4-Tetraeder verknüpft werden. Hohlräume dieses Gerüstes werden von ungeordnet orientierten [Al(H2O)6]-Oktaedern eingenommen. Es wird gezeigt, daß Al als wesentlicher Bestandteil dieses Voltaits angesehen werden muß.
Mit 2 Abbildungen 相似文献
The crystal structure of voltaite, K2Fe5 2+Fe3 3+Al[SO4]12·18H2O
Summary The crystal structure of synthetic voltaite, K2Fe5 2+Fe3 3+Al[SO4]12· · 18 H2O, cubic hexakis-octahedral, space groupFd3c–O h 8,a 0=27.254 ,Z=16, was determined from photographic X-ray data. The structure was solved by Patterson and Fourier-methods with the aid of multiple isomorphic substitution. Least squares refinement with anisotropic temperature factors resulted inR=0.033 for 726 observedF hkl . The dominant structural feature is a continous framework composed of [Fe3+O6]-octahedra, [Fe 5 6/2+ Fe 1 6/3+ O4(H2O)2]-octahedra and [K+O12]-polyhedra linked by SO4-tetrahedra. The arrangement gives rise to cages occupied by disordered [Al(H2O)6]-octahedra. It is shown that Al must be considered to be a essential constituent of such voltaites.
Mit 2 Abbildungen 相似文献
10.
Richard A. Robie Howard T. Evans Jr. Bruce S. Hemingway 《Physics and Chemistry of Minerals》1988,15(4):390-397
The heat capacity of ilvaite from Seriphos, Greece was measured by adiabatic shield calorimetry (6.4 to 380.7 K) and by differential
scanning calorimetry (340 to 950 K). The thermal expansion of ilvaite was also investigated, by X-ray methods, between 308
and 853 K.
At 298.15 K the standard molar heat capacity and entropy for ilvaite are 298.9±0.6 and 292.3±0.6 J/(mol. K) respectively.
Between 333 and 343 K ilvaite changes from monoclinic to orthorhombic. The antiferromagnetic transition is shown by a hump
in C
p
0
with a Néel temperature of 121.9±0.5 K. A rounded hump in C
p
0
between 330 and 400 K may possibily arise from the thermally activated electron delocalization (hopping) known to take place
in this temperature region. 相似文献
11.
Pekov I. V. Zubkova N. V. Chukanov N. V. Yapaskurt V. O. Turchkova A. G. Ksenofontov D. A. Pushcharovsky D. Yu. 《Geology of Ore Deposits》2022,64(7):452-469
Geology of Ore Deposits - Natisite, a natural tetragonal (P4/nmm) modification of Na2TiSiO5 = Na2TiO(SiO4) is an abundant indicator mineral of relatively low-temperature (no higher than... 相似文献
12.
13.
An in situ high pressure X-ray diffraction study on synthetic pure ilvaite powder has been performed using a diamond anvil cell. A phase transition from monoclinic to orthorhombic (Pbnm) has been observed at 2.25 Gpa, which can be described as a λ-transition. 相似文献
14.
Anastasia Chopelas 《Physics and Chemistry of Minerals》2005,32(8-9):525-530
Single-crystal Raman spectra of synthetic end-member uvarovite (Ca3Cr2Si3O12) and of a binary solution (59% uvarovite, 41% andradite) have been measured using single crystal techniques. For each of
these garnets, 22 and 21 of the 25 Raman modes were located, respectively. The spectra for uvarovite garnets closely resemble
those of the other calcic garnets, grossular, and andradite. The modes for uvarovites do not fit into the same trends as established
by the other five anhydrous end-member garnets: the high energy “internal” Si–O modes do not depend on lattice constant in
uvarovite. They exceed frequencies for both andradite and grossular. This is likely due to the large crystal field stabilization
energy of trivalent chromium. The low energy and midrange modes are at similar frequencies to the other calcic garnets. 相似文献
15.
The distribution of Fe3+ and Ga3+ between the two tetrahedral sites in three synthetic melilites has been studied by using 57Fe Mössbauer spectroscopy. In the melilite, (Ca2Ga2SiO7)50 (Ca2Fe3+GaSiO7)50 (mol %), the distribution of Fe3+ and Ga3+ in T1 and T2 sites is apparently random, which can be explained in terms of the electrostatic valence rule. However in the melilites, (Ca2MgSi2O7)52 (Ca2Fe3+GaSiO7)42 (Ca2Ga2SiO7)6 and (Ca2MgSi2O7)62 (Ca2Fe3+GaSiO7)36 (Ca2Ga2SiO7)2 (mol %), Fe3+ shows preference for the more ionic T1 site and Ga3+ for the more covalent T2 site. If the electronegativity of Ga3+ is assumed to be larger than that of Fe3+, the mode of distribution of Fe3+ and Ga3+ can be explained in terms of our previous hypothesis that a large electronegativity induces a stronger preference for the more covalent T2 site. 相似文献
16.
Dualite has been found at Mount Alluaiv, the Lovozero Pluton, the Kola Peninsula in peralkaline pegmatoid as sporadic, irregularly
shaped grains up to 0.3–0.5 mm across. K-Na feldspar, nepheline, sodalite, cancrinite, aegirine, alkaline amphibole, eudialyte,
lovozerite, lomonosovite, vuonnemite, lamprophyllite, sphalerite, and villiaumite are associated minerals. Dualite is yellow,
transparent or translucent, with conchoidal fracture. The new mineral is brittle, with vitreous luster and white streaks.
The Mohs hardness is 5. The measured density is 2.84(3) g/cm3 (volumetric method); the calculated density is 2.814 g/cm3. Dualite dissolves and gelates in acid at room temperature. It is nonfluorescent. The new mineral is optically uniaxial and
positive; ω = 1.610(1), ɛ = 1.613(1). Dualite is trigonal, space group R3m. The unit cell dimensions are a = 14.153(9), c = 60.72(5) ?, V = 10533(22) ?, Z = 3. The strongest reflections in the X-ray powder pattern [d, ? (I,%)(hkl)] are as follows: 7.11(40)(110), 4.31(50)(0.2.10), 2.964(100)(1.3.10), 2.839(90)(048), 2.159(60)(2.4.10, 0.4.20), 1.770(60)(2.4.22,
4.0.28, 440), 1362(50)(5.5.12, 3.0.42). The chemical composition (electron microprobe, H2O calculated from X-ray diffraction data) is as follows, wt %: 17.74 Na2O, 0.08 K2O, 8.03 CaO, 1.37 SrO, 0.29 BaO, 2.58 MnO, 1.04 FeO, 0.79 La2O3, 1.84 C2O3, 0.88 Nd2O3, 0.20 Al2O3, 51.26 SiO2, 4.40 TiO2, 5.39 ZrO2, 1.94 Nb2O5, 0.58 Cl, 1.39 H2O,-O = 0.13 Cl2; they total is 99.67. The empirical formula calculated on the basis of 106 cations as determined by crystal structure is
(Na29.79Ba0.1K0.10)Σ30(Ca8.55Na1.39REE1.27Sr0.79)Σ12 · (Na3.01Mn1.35Fe0.872+Ti0.77)Σ6(Zr2.61Nb0.39)Σ3 (Ti2.52Nb0.48)Σ3(Mn0.82Si0.18)Σ1(Si50.77Al0.23)Σ51 O144[(OH)6.54(H2O)1.34·Cl0.98]Σ8.86). The simplified formula is Na30(Ca,Na,Ce,Sr)12(Na,Mn,Fe,Ti)6Zr3Ti3 MnSi51O144 (OH,H2O,Cl)9). The name dualite is derived from Latin dualis (dual) alluding to the dual taxonomic membership of this mineral, which is at the same time zirconosilicate and titanosilicate.
The crystal structure is characterized by two module types (alluivite-like and eudialyte-like) alternating along a threefold
axis with a doubled c period relative to eudialyte and close chemical affinity to rastsvetaevite (Khomyakov et al., 2006a) and labyrynthite (Khomyakov
et al., 2006b). According to the authors’ crystal chemical taxonomy of the eudialyte group, the new mineral belongs to one
of three subgroups characterized by a 24-layered structural framework. Dualite is a mineral formed during the final stages
of peralkaline pegmatite formation. The type material of dualite is deposited at the Fersman Mineralogical Museum, Russian
Academy of Sciences, Moscow.
Original Russian Text ? A.P. Khomyakov, G.N. Nechelyustov, R.K. Rastsvetaeva, 2007, published in Zapiski Rossiiskogo Mineralogicheskogo
Obshchestva, 2007, Pt CXXXVI, No. 4, pp. 68–73.
Approved by the Commission on New Minerals and Mineral Names, International Mineralogical Association, July 8, 2005. 相似文献
17.
Mn3+-bearing piemontites and orthozoisites, Ca2(Al3-pMn3+ p)-(Si2O7/SiO4/O/OH), have been synthesized on the join Cz (p = 0.0)-Pm (p = 3.0) of the system CaO-Al2O3-(MnO·MnO2)-SiO2-H2O atP = 15 kb,T= 800 °C, and \(f_{O_2 } \) of the Mn2O3/MnO2 buffer. Pure Al-Mn3+-piemontites were obtained with 0.5≦p≦1.75, whereas atp=0.25 Mn3+-bearing orthozoisite (thulite) formed as single phase product. The limit of piemontite solid solubility is found near p=1.9 at the above conditions. Withp>1.9, the maximum piemontite coexisted with a new high pressure phase CMS-X1, a Ca-bearing braunite (Mn 0.2 2+ Ca0.8)Mn 6 3+ O8(SiO4), and quartz. Al-Mn3+-piemontite lattice constants (LC),b 0,c 0,V 0, increase with increasingp:
18.
Zolotarev Andrey A. Zhitova Elena S. Gabdrakhmanova Faina A. Krzhizhanovskaya Maria G. Zolotarev Anatoly A. Krivovichev Sergey V. 《Mineralogy and Petrology》2017,111(6):843-851
Mineralogy and Petrology - The crystal structure of batisite, Na2BaTi2 (Si4O12)O2, from the Inagli massif (Aldan, Yakutia, Russia) was refined to R 1 = 0.032 for 1449 unique... 相似文献
19.
K. Abraham W. Gebert O. Medenbach W. Schreyer G. Hentschel 《Contributions to Mineralogy and Petrology》1983,82(2-3):252-258
Eifelite of variable composition is uniaxial positive withn 0 near 1.543 andn e near 1.544, a between 10.14 and 10.15 Å, andc about 14.22 Å, space groupP 6/m 2/c 2/c. There is a complete series of solid solution between the eifelite end member KNa3Mg4Si12O30 and roedderite, KNaMg5Si12O30, following the 2 Na?Mg substitution. Both eifelite and roedderite have milarite-type structures, but Na is always in six-coordinated sites: In roedderite Na occupies solely a newly defined B′[6]-position which is slightly displaced alongc from the ideal B[9]-position lying on the (001/2)-mirror plane in K2Mg5Si12O30. In eifelite Na is located both inB′[6] and in theA [6]-positions, where it partially replaces Mg. Eifelite has the highest cation occupancy of all osumilite group minerals known thus far. Both eifelite and roedderite occur in vesicles of contact metamorphosed basement xenoliths ejected with the leucite tephrite lava of the Quaternary Bellerberg volcano in the Eifel, West Germany. They are considered to be precipitates from highly alkaline, MgSi-rich, but Al-deficient gas phases that originated through interaction of gaseous igneous differentiates with the xenoliths. 相似文献
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