Ephesite,Na(LiAl2) [Al2Si2O10] (OH)2: I. thermal stability and standard state thermodynamic properties     

Udo Warhus  Niranjan D. Chatterjee 《Contributions to Mineralogy and Petrology》1984,85(1):74-79

Ephesite, Na(LiAl₂) [Al₂Si₂O₁₀] (OH)₂, has been synthesized for the first time by hydrothermal treatment of a gel of requisite composition at 300≦T(° C)≦700 and \(P_{H_2 O}\) upto 35 kbar. At \(P_{H_2 O}\) between 7 and 35 kbar and above 500° C, only the 2M₁ polytype is obtained. At lower temperatures and pressures, the 1M polytype crystallizes first, which then inverts to the 2M₁ polytype with increasing run duration. The X-ray diffraction patterns of the 1M and 2M₁ poly types can be indexed unambiguously on the basis of the space groups C2 and Cc, respectively. At its upper thermal stability limit, 2M₁ ephesite decomposes according to the reaction (1) $$\begin{gathered} {\text{Na(LiAl}}_{\text{2}} {\text{) [Al}}_{\text{2}} {\text{Si}}_{\text{2}} {\text{O}}_{{\text{10}}} {\text{] (OH)}}_{\text{2}} \hfill \\ {\text{ephesite}} \hfill \\ {\text{ = Na[AlSiO}}_{\text{4}} {\text{] + LiAl[SiO}}_{\text{4}} {\text{] + }}\alpha {\text{ - Al}}_{\text{2}} {\text{O}}_{\text{3}} {\text{ + H}}_{\text{2}} {\text{O}} \hfill \\ {\text{nepheline }}\alpha {\text{ - eucryptite corundum}} \hfill \\ \end{gathered}$$ Five reversal brackets for (1) have been established experimentally in the temperature range 590–750° C, at \(P_{H_2 O}\) between 400 and 2500 bars. The equilibrium constant, K, for this reaction may be expressed as (2) $$log K{\text{ = }}log f_{{\text{H}}_{\text{2}} O}^* = 7.5217 - 4388/T + 0.0234 (P - 1)T$$ where \(f_{H_2 O}^* = f_{H_2 O} (P,T)/f_{H_2 O}^0\) (1,T), with T given in degrees K, and P in bars. Combining these experimental data with known thermodynamic properties of the decomposition products in (1), the following standard state (1 bar, 298.15 K) thermodynamic data for ephesite were calculated: H _f,298.15 ⁰ =-6237372 J/mol, S _298.15 ⁰ =300.455 J/K·mol, G _298.15 ⁰ =-5851994 J/mol, and V _298.15 ⁰ =13.1468 J/bar·mol.  相似文献   

Lithogeochemistry as an indicator of uranium and tin mineralization, South Mountain Batholith, Nova Scotia, Canada     

G.K. Muecke  A.K. Chatterjee   《Journal of Geochemical Exploration》1983,19(1-3)

Uranium and tin occurrences in the South Mountain Batholith are preferentially found in or near a para-intrusive rock suite which is characterized by strong granophile element enrichments. Furthermore, bodies which show a Th-enrichment trend with increasing differentiation appear to be more favorable exploration targets than spatially associated bodies in which Th is depleted.  相似文献   

Non‐stationary seismic response of tanks with soil interaction by wavelets     

Pranesh Chatterjee  Biswajit Basu 《地震工程与结构动力学》2001,30(10):1419-1437

A wavelet‐based random vibration theory has been developed for the non‐stationary seismic response of liquid storage tanks including soil interaction. The ground motion process has been characterized via estimates of statistical functionals of wavelet coefficients obtained from a single time history of ground accelerations. The tank–liquid–soil system has been modelled as a two‐degree‐of‐freedom (2‐DOF) system. The wavelet domain equations have been formulated and the wavelet coefficients of the required response state are obtained by solving two linear simultaneous algebraic equations. The explicit expression for the instantaneous power spectral density function (PSDF) in terms of the functionals of the input wavelet coefficients has been obtained. The moments of this PSDF are used to estimate the expected pseudo‐spectral acceleration (PSA) response of the tank. Parametric variations are carried out to study the effects of tank height, foundation natural frequency, shear wave velocity of soil and ratio of the mass of tank (including liquid) to the mass of foundation on the PSA responses of tanks. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Experimental and thermodynamic study of heterogeneous and homogeneous equilibria in the system NaAlSiO4-SiO2     

Tanja Waterwiese  Niranjan D. Chatterjee  Ivana Dierdorf  Jörg Göttlicher  Herbert Kroll 《Contributions to Mineralogy and Petrology》1995,121(1):61-73

Internally consistent thermodynamic datasets available at present call for a further improvement of the data for nepheline (Holland and Powell 1988; Berman 1991). Because nepheline is a common rock-forming mineral, an attempt has been made to improve on the present state of knowledge of its thermodynamic properties. To achieve that goal, two heterogeneous reactions involving nepheline, albite, jadeite and a-quartz in the system NaAlSiO₄-SiO₂ have been reversed bylong duration runs in the range 460 ≤ T(°C) ≤ 960 and 10 ≤ P(kbar) ≤ 22. Given sufficiently long run times, thealbite run products approach internal equilibrium with respect to their Al,Si order-disorder states. Using appropriate thermochemical, thermophysical, and volumetric data, Landau expansion for albite, and the relevant reaction reversals, a refined thermodynamic dataset (Δ_fH_i⁰ and S_i⁰) has been derived for nepheline, jadeite, a-quartz, albite, and monalbite. Our refined data agree very well with theircalorimetric counterparts, but have smaller uncertainties. The refined dataset for Δ_fH_i⁰ and S_i⁰, including their uncertainties and correlation, help generate the NaAlSiO₄-SiO₂ phase diagram including 2a confidence interval for eachP-T curve (Fig. 5). Editorial responsibility: W. Schreyer  相似文献   

Mildly alkaline basalts from Pavagadh Hill, India: Deccan flood basalts with an asthenospheric origin     

J. D. Greenough  K. R. Hari  A. C. Chatterjee  M. Santosh 《Mineralogy and Petrology》1998,62(3-4):223-245

Summary Of twelve flows at Pavagadh Hill, the two three-phenocryst-basalt flows with Mg#0.70 and Ni/MgO33 are the most primitive and perhaps as primitive as any basalts in the Deccan province. Scatter on variation diagrams and the occurrence of primitive flows at two different levels in the volcanic sequence implies that most rocks are probably not, strictly speaking, comagmatic. Nevertheless, mass balance calculations indicate a generalized differentiation scheme from primitive basalt to hawaiite that involved removal of olivine, augite, plagioclase and Fe-Ti oxides in the proportions 40:33:22:5 with 50% of the magma remaining. Crustal assimilation had a minimal effect on evolution of the basalts but rhyolites at the top of the volcanic sequence may have been produced by crustal melting following prolonged heat release from alkali basalt pooled along fault zones in the continental crust. Major element based calculations indicate that the most primitive basalts were generated by 7 to 10% melting of mantle peridotite. These low percentages of melting, typical of alkali basalts, are consistent with the steep slopes on chondrite-normalized REE diagrams. Low heavy REE concentrations point to residual garnet in the source region. Incompatible element concentrations (e.g. Rb, Ba, Zr, La) in Pavagadh basalts exceed those in Deccan tholeiitic basalts but are substantially lower than those reported for some other Deccan alkali basalts. Obviously Pavagadh basalts do not reflect the lowest percentages of melting and greatest amount of source region metasomatic enrichment attained in the Deccan province. Deccan tholeiitic and alkali basalts are largely characterized by low La/Nb ratios and high La/Ba ratios similar to those in oceanic island basalts. This indicates minimal involvement of the subcontinental lithospheric mantle in their petrogenesis. Comparison with continental mafic magma provinces where a subcontinental lithospheric mantle imprint is common indicates long periods of extension and/or melting of mantle lithosphere still hot from pre-extension subduction are more likely to produce magmas bearing the lithospheric imprint.

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Alkalische Basalte von Pavagadh Hill, Indien: Deccan-Flutbasalte von Astenosphärischer Herkunft

Zusammenfassung Im Gebiet von Pavagadh Hill, Indien, treten 12 Spät-Deccan und rhyolithische alkalibasaltische Ergüsse und Intrusiva auf. Variationsdiagramme zeigen, daß die Abfolge nicht komagmatisch ist. Zusammen mit Berechnungen der Massenbilanz unterstützen sie vielmehr ein Zwei-Stadienmodell für die Entstehung von Hawaiiten aus sehr primitiven (i.e. Mg#=Mg/(Mg+.(0.9*Fe_totat)) at.%0.70) Basalten. Olivin und Augit dominierten die frühe Fraktionierung während Augit vorherrschte als der Magmaanteil von 65% auf 50% sank. Die Entfernung von Plagioklas spielte bei der Differentiation nur eine geringe Rolle. Niedrige Th/Nb (0,2), Rb/Sr(<0,12) und K/NbVerhältnisse geben keine Hinweise auf signifikante Assimilation von Krustenmaterial. Die Seltene-Erd-Verteilungsmuster (SEE), niedrige Gehalte an schweren SEE sowie die Hauptelementspektren der Alkalibasalte weisen auf eine granatführende Ursprungsregion und auf einen Aufschmelzungsgrad von nur 7% bis 10% hin. Es gibt jedoch auch stärker alkalische (höhere Rb, Zr etc.) Deccanbasalte (i.e. Rajpipla). Die Assoziation von Deccanalkalibasalten, Rhyolithen und Störungszonen zeigt, daß letztere die Extraktion von Magma aus dem Mantel erleichterten und dazu führten, daß Magma aus Magmenkammern Krustenschmelzen (Rhyolithe) produzierte. Deccanbasalte tendieren zu hohen La/Ba und niedrigen La/Nb-Verhältnissen; dies weist auf eine asthenosphärische Herkunft hin, selbst wenn die Gesteine verhältnismäßig spät gebildet wurden (i.e. Pavagadh). Längere Perioden von Krustenextension oder von Subduktion, die der Extension vorhergeht, führt offensichtlich zur Entstehung von Magmen mit einer lithosphärischen Komponente.

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The Bayesian approach to an internally consistent thermodynamic database: theory, database, and generation of phase diagrams     

Niranjan D. Chatterjee  Ralf Krüger  Gerd Haller  Walter Olbricht 《Contributions to Mineralogy and Petrology》1998,133(1-2):149-168

An internally consistent thermodynamic dataset has been derived for 148 endmember phases (145 solids and 3 fluids) comprising the elements Li, Na, K, Be, Mg, Ca, Ti, Cr, Mn, Fe, Zn, Al, Si, C, H, and O. This has been achieved by simultaneous treatment of phase property (like standard enthalpy of formation, standard entropy, molar heat capacity, molar volume, thermal expansivity, bulk modulus etc.) and reaction reversal data by the Bayesian method. The theory underlying the approach, and the computational methods involved, are briefly outlined. (For the benefit of readers unfamiliar with inference statistics, the basic concepts of the Bayes method are also presented in such a way that they can be grasped intuitively.) Although not yet addressed, this method can be extended to refine the thermodynamic mixing properties of crystalline solutions. The sources of the input data, culled from the literature, are summarized in the Appendix. The resulting database is succinctly documented in this paper. It includes the enthalpies of formation and entropies, their uncertainties, and the correlation among them. The database allows calculation of P-T, T-X _CO2, P-X _CO2, and T-f _O2 sections, with error propagation into the computed phase diagrams on a routine basis. A user-friendly computer program has been written to generate such phase diagrams. It is public domain software. The software and the thermodynamic database (which includes a complete documentation of the thermodynamic data above and beyond those listed (Table 2, here) may be downloaded from the web site http://homepage.ruhr-uni-bochum.de/niranjan.chatterjee/Index.htm. Examples of computed phase diagrams are given to illustrate the quality of the data and the capabilities of the software. Received: 11 March 1998 / Accepted: 11 June 1998  相似文献   

Heat capacity of wadeite-type K2Si4O9 and the pressure-induced stable decomposition of K-feldspar     

Detlef W. Fasshauer  Bernd Wunder  Niranjan D. Chatterjee  Günther W. H. Höhne 《Contributions to Mineralogy and Petrology》1998,131(2-3):210-218

The heat capacity of synthetic, stoichiometric wadeite-type K₂Si₄O₉ has been measured by DSC in the 195≤T(K)≤598 range. Near the upper temperature limit of our data, the heat capacity observed by DSC agrees with that reported by Geisinger et al. (1987) based on a vibrational model of their infrared and Raman spectroscopic data. However, with decreasing temperature, the Cp observed by DSC is progressively higher than that predicted from the vibrational model, suggesting that the standard entropy of K₂Si₄O₉ is likely to be larger than 198.9 ± 4.0 J/K · mol computed from the spectroscopic data. A fit to the DSC data gave: Cp(T) = 499.13 (±1.87) − 4.35014 · 10³(±3.489 · 10¹) · T ^−0.5, with T in K and average absolute percent deviation of 0.37%. The room-temperature compressibilities of kalsilite and leucite, hitherto unknown, have been measured as well. The data, fitted to the Murnaghan equation of state, gave K _o = 58.6 GPa, K _o ^′ = 0.1 for kalsilite and K _o = 45 GPa, K _o ^′ = 5.7 for α-leucite. Apart from the above mentioned data on the properties of the individual phases, we have also obtained reaction-reversals on four equilibria in the system K₂O-Al₂O₃-SiO₂. The Bayesian method has been used simultaneously to process the properties of 13 phases and 15 reactions between them to derive an internally consistent thermodynamic dataset for the K₂O-Al₂O₃-SiO₂ ternary. The enthalpy of formation of K₂Si₄O₉ wadeite is in perfect agreement with its revised calorimetric value, the standard entropy is 232.1 ± 10.4 J/K · mol, ∼15% higher than that implied by vibrational modeling. The phase diagram, generated from our internally consistent thermodynamic dataset, shows that for all probable P-T trajectories in the subduction regime, the stable pressure-induced decomposition of K-feldspar will produce coesite + kalsilite rather than coesite + kyanite + K₂Si₄O₉ (cf. Urakawa et al. 1994). Received: 11 June 1997 / Accepted: 2 December 1997  相似文献   

Dynamical Initialization of Boundary-Layer Data     

G. K. Sen  M. Chatterjee  D. K. Sinha 《Boundary-Layer Meteorology》1998,87(3):509-514

A procedure for the dynamic initialization of wind and temperature fields within the atmospheric boundary layer (ABL) is presented. The procedure uses transilient turbulence theory to assess the turbulent fluxes from observed wind and temperature data, which are used to estimate the eddy transfer coefficients, so enabling a local closure ABL model to be integrated forward in time to a new steady state. The method has been applied to initialize kytoon data taken at Kharagpur (22.3° N, 87.2° E) during the MONTBLEX field programme. Results of a case study for 17 June 1990 are discussed.  相似文献   

Application of Two Turbulence Closure Schemes in the Modelling of Tidal Currents and Salinity in the Hooghly Estuary     

P. C. Sinha  Y. R. Rao  S. K. Dube  C. R. Murthy  A. K. Chatterjee 《Estuarine, Coastal and Shelf Science》1999,48(6):649

This paper has two purposes. The first is to study the circulation and salinity in Hooghly Estuary, along the east coast of India and the second is to compare the performance of two turbulence closure schemes by modelling it. A breadth averaged numerical model using a sigma co-ordinate system in the vertical is briefly described. Vertical diffusion of momentum and salt are parameterized by a simple first-order turbulent closure or by a one equation model for turbulent kinetic energy (TKE) which uses a specified mixing length. The results are compared with the available neap and spring tide observations along the estuary for both low and high discharge periods.The computed elevations and currents are in reasonable agreement with the observations showing no major differences in vertical current profiles by both the turbulent schemes. However, there is a slight under-prediction of bottom currents. The salinity profiles predicted by TKE model show better matching with observations. Statistical tests are also conducted to study the comparative performance of the turbulent closure schemes. The maintenance of two layer structure in residual currents and salt variability are also studied by using the model.  相似文献   

Flood inundation modeling using MIKE FLOOD and remote sensing data     

S. Patro  C. Chatterjee  S. Mohanty  R. Singh  N. S. Raghuwanshi 《Journal of the Indian Society of Remote Sensing》2009,37(1):107-118

A coupled 1D-2D hydrodynamic model, MIKE FLOOD was used to simulate the flood inundation extent and flooding depth in the delta region of Mahanadi River basin in India. Initially, the 1D model MIKE 11 was calibrated using river water level and discharge data of various gauging sites for the monsoon period (June to October) of the year 2002. Subsequently, the calibrated set up was validated using both discharge and water level data for the same period of the year 2001. The performance of calibration and validation results of MIKE 11 were evaluated using different performance indices. A bathymetry of the study area with a spatial resolution of 90m was prepared from SRTM DEM and provided as an input to the 2D model, MIKE 21. MIKE 11 and MIKE 21 models were then coupled using lateral links to form the MIKE FLOOD model set up for simulating the two dimensional flood inundations in the study area. Flood inundation is simulated for the year 2001 and the maximum flood inundation extent simulated by the model was compared with the corresponding actual inundated area obtained from IRS-1D WiFS image.  相似文献