scholarly journals Equation of State for Natural Almandine, Spessartine, Pyrope Garnet: Implications for Quartz-In-Garnet Elastic Geobarometry

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 458
Author(s):  
Suzanne R. Mulligan ◽  
Elissaios Stavrou ◽  
Stella Chariton ◽  
Oliver Tschauner ◽  
Ashkan Salamat ◽  
...  

The equation of state (EoS) of a natural almandine74spessartine13pyrope10grossular3 garnet of a typical composition found in metamorphic rocks in Earth’s crust was obtained using single crystal synchrotron X-ray diffraction under isothermal room temperature compression. A third-order Birch-Murnaghan EoS was fitted to P-V data and the results are compared with published EoS for iron, manganese, magnesium, and calcium garnet compositional end-members. This comparison reveals that ideal solid solution mixing can reproduce the EoS for this intermediate composition of garnet. Additionally, this new EoS was used to calculate geobarometry on a garnet sample from the same rock, which was collected from the Albion Mountains of southern Idaho. Quartz-in-garnet elastic geobarometry was used to calculate pressures of quartz inclusion entrapment using alternative methods of garnet mixing and both the hydrostatic and Grunëisen tensor approaches. QuiG barometry pressures overlap within uncertainty when calculated using EoS for pure end-member almandine, the weighted averages of end-member EoS, and the EoS presented in this study. Grunëisen tensors produce apparent higher pressures relative to the hydrostatic method, but with large uncertainties.

2015 ◽  
Vol 79 (2) ◽  
pp. 285-294 ◽  
Author(s):  
F. Nestola ◽  
B. Periotto ◽  
C. Anzolini ◽  
G. B. Andreozzi ◽  
A. B. Woodland ◽  
...  

AbstractIn this work a single crystal of synthetic hercynite, FeAl2O4, was investigated by X-ray diffraction up to 7.5 GPa and at room temperature, in order to determine its pressure–volume equation of state. The unit-cell volume decreases non-linearly with a reduction of 3.4% (i.e. 18.43 Å3). The pressure–volume data were fitted to a third-order Birch-Murnaghan equation of state providing the following coefficients: V0 = 542.58(3)Å3, KT0 = 193.9(1.7) GPa, K' = 6.0(5). These results are consistent with previous investigations of Cr and Al spinels measured with the same experimental approach but the KT0 differs significantly from the experimental determination carried out more than 40 years ago by Wang and Simmons (1972) by the pulse echo overlap method. Our new results were used to redetermine the FeAl2O4(hercynite) = FeO(wüstite) + Al2O3(corundum) equilibrium in P–T space and obtain geobarometric information for Cr-Al spinels found as inclusions in diamond.


2005 ◽  
Vol 69 (3) ◽  
pp. 317-323 ◽  
Author(s):  
M. H. Manghnani ◽  
G. Amulele ◽  
J. R. Smyth ◽  
C. M. Holl ◽  
G. Chen ◽  
...  

AbstractThe equation of state of Fo90 hydrous ringwoodite has been measured using X-ray powder diffraction to 45 GPa at the GSECARS beam line at the Advanced Photon Source synchrotron at Argonne National Laboratory. The sample was synthesized at 1400°C and 20 GPa in the 5000 ton multi anvil press at Bayerisches Geoinstitut in Bayreuth. The sample has the formula Mg1.70Fe0.192+ Fe0.023+H0.13- Si1.00O4 as determined by electron microprobe, Fourier transform infrared and Mössbauer spectroscopies, and contains ~0.79% H2O by weight. Compression of the sample had been been measured previously to 11 GPa by single crystal X-ray diffraction. A third-order Birch-Murnaghan equation of state fit to all of the data gives V0 = 530.49±0.07 Å3, K0 = 174.6±2.7 GPa and K' = 6.2±0.6. The effect of 1% H incorporation in the structure on the bulk modulus is large and roughly equivalent to an increase in the temperature of ∼600°C at low pressure. The large value of K' indicates significant stiffening of the sample with pressure so that the effect of hydration decreases with pressure.


2015 ◽  
Vol 48 (6) ◽  
pp. 1914-1920 ◽  
Author(s):  
Oliver T. Lord ◽  
Andrew R. Thomson ◽  
Elizabeth T. H. Wann ◽  
Ian G. Wood ◽  
David P. Dobson ◽  
...  

The equation of state of the orthorhombic phase of NiSi withPmmnsymmetry has been determined at room temperature from synchrotron-based X-ray diffraction measurements of its lattice parameters, made in a diamond anvil cell. Measurements were performed up to 44 GPa, using Ne as the pressure medium and Au as the pressure standard. The resulting pressure–volume (P–V) data have been fitted with a Birch–Murnaghan equation of state of third order to yieldV0= 11.650 (7) Å3 atom−1,K0= 162 (3) GPa andK0′ = 4.6 (2). In addition,P–Vdata have been collected on Ni53Si47in the B20 structure using both Ne and He as the pressure media and Cu and Au as the pressure standards, also to 44 GPa. A fit using the same Birch–Murnaghan equation of state of third order yieldsV0= 11.364 (6) Å3 atom−1,K0= 171 (4) GPa andK0′ = 5.5 (3).


2000 ◽  
Vol 64 (3) ◽  
pp. 561-567 ◽  
Author(s):  
W. A. Crichton ◽  
N. L. Ross

AbstractThe isothermal equation of state (EoS) of phase E, Mg1.96(7)Fe0.072(5)Si1.04(5)H3.7(8)O6, has been determined using high-pressure single-crystal X-ray diffraction. A third-order Birch Murnaghan EoS fit to pressue-volume data collected from room pressure and temperature to 6.7 GPa reveals that phase E has the lowest bulk modulus, KT = 92.9(7) GPa, and highest pressure derivative of the bulk modulus, K' = 7.3(2), for any dense hydrous magnesium silicate (DHMS) yet measured. A parameterized third-order Birch-Murnaghan EoS was also fit to the unit-cell parameters which display significant curvature with increasing pressure. This analysis shows that the c-axis (Kc = 89.1(10) GPa) is 6% more compressible than the a-axis (Ka = 94.8(6) GPa), with little of the anisotropy commonly observed in other layered structures. The high K' is indicative of the similarity to layers of the brucite structure. The introduction of interlayer cation polyhedra to the structure serves to reduce both the anisotropy, by reducing the compressibility perpendicular to the sheets, and the ability to shear, by increasing the coherence between layers.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. Lütgert ◽  
J. Vorberger ◽  
N. J. Hartley ◽  
K. Voigt ◽  
M. Rödel ◽  
...  

AbstractWe present structure and equation of state (EOS) measurements of biaxially orientated polyethylene terephthalate (PET, $$({\hbox {C}}_{10} {\hbox {H}}_8 {\hbox {O}}_4)_n$$ ( C 10 H 8 O 4 ) n , also called mylar) shock-compressed to ($$155 \pm 20$$ 155 ± 20 ) GPa and ($$6000 \pm 1000$$ 6000 ± 1000 ) K using in situ X-ray diffraction, Doppler velocimetry, and optical pyrometry. Comparing to density functional theory molecular dynamics (DFT-MD) simulations, we find a highly correlated liquid at conditions differing from predictions by some equations of state tables, which underlines the influence of complex chemical interactions in this regime. EOS calculations from ab initio DFT-MD simulations and shock Hugoniot measurements of density, pressure and temperature confirm the discrepancy to these tables and present an experimentally benchmarked correction to the description of PET as an exemplary material to represent the mixture of light elements at planetary interior conditions.


Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 516
Author(s):  
Timofey Fedotenko ◽  
Saiana Khandarkhaeva ◽  
Leonid Dubrovinsky ◽  
Konstantin Glazyrin ◽  
Pavel Sedmak ◽  
...  

We report the high-pressure synthesis and the equation of state (EOS) of a novel nickel carbide (Ni3C). It was synthesized in a diamond anvil cell at 184(5) GPa through a direct reaction of a nickel powder with carbon from the diamond anvils upon heating at 3500 (200) K. Ni3C has the cementite-type structure (Pnma space group, a = 4.519(2) Å, b = 5.801(2) Å, c = 4.009(3) Å), which was solved and refined based on in-situ synchrotron single-crystal X-ray diffraction. The pressure-volume data of Ni3C was obtained on decompression at room temperature and fitted to the 3rd order Burch-Murnaghan equation of state with the following parameters: V0 = 147.7(8) Å3, K0 = 157(10) GPa, and K0' = 7.8(6). Our results contribute to the understanding of the phase composition and properties of Earth’s outer core.


1988 ◽  
Vol 11 (6-11) ◽  
pp. 1005-1014 ◽  
Author(s):  
S.C. Agarwala ◽  
C. Chatterjee ◽  
S. Gupta ◽  
N. Nautiyal

2008 ◽  
Vol 72 (4) ◽  
pp. 987-990 ◽  
Author(s):  
L. Secco ◽  
F. Nestola ◽  
A. Dal Negro

AbstractThree natural crystals of the wulfenite (PbMoO4)—stolzite (PbWO4) series were investigated by single-crystal X-ray diffraction. The results indicate that the symmetry is I41/a from nearly pure wulfenite to intermediate compositions, in contrast to previous work which claimed a symmetry change to 74 symmetry (acentric) for intermediate compositions compared with I41/a (centric space group) for the end-members. The results reported here show that the reflections violating I41/a symmetry observed in this work and in a previous study are related primarily to λ/2 effects, even if Renninger effects are not excluded. Consequently, we find that the I41/a symmetry is retained throughout the wulfenite— stolzite.


2011 ◽  
Vol 10 (03) ◽  
pp. 433-440 ◽  
Author(s):  
A. A. DAKHEL ◽  
F. Z. HENARI

Nanoparticles of silver-embedded indium oxide thin films have been prepared on glass and silicon substrates. Silver concentration were 3 wt.% and 5 wt.% as measured by X-ray fluorescence. X-ray diffraction reveals that indium oxide of these samples remains amorphous even after pre-annealing at 400°C. The optical absorption of the samples manifests the surface plasmon resonance (SPR) phenomena, which varies with Ag content. The Ag nanoparticles radius was estimated with Mie classical theory by using the SPR data analysis. The nonlinear optical properties of films on glass substrate were investigated using z-scan technique. Under cw excitation the films exhibit large reverse saturation absorption and negative nonlinearities. The real and imaginary parts of third order susceptibility of the samples were measured and the imaginary part which arise from the change in absorption is found to be dominant.


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