Linear thermal expansion coefficients of orthopyroxene to 1000°C

Frisillo, A. L.; Buljan, S. T.

doi:10.1029/jb077i035p07115

Cited by 69 publications

(8 citation statements)

References 3 publications

(3 reference statements)

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“…2). However, there is a significant difference between the thermal expansivity from the present study and the results of Frisillo & Buljan (1972) and Dietrich & Arndt (1982), both of whom used a Fe-rich orthopyroxene in their experiments (Table 1). Because nearly pure Mg end-mem- Fig.…”

Section: Resultscontrasting

confidence: 88%

“…ber enstatite was used in the present study, the differences in thermal expansivity might be ascribed to a compositional effect of Mg-Fe substitution. However, the thermal expansion reported by Frisillo & Buljan (1972) is higher than ours by about 12x10 -6 , and that of Dietrich & Arndt (1982) is lower than the present result by roughly an equivalent amount. Therefore, differences in composition do not appear to explain the extreme thermal expansion values of orthoenstatite reported by Frisillo & Buljan (1972) and Dietrich & Arndt (1982), and the reasons for discrepancies between these two studies are not clear.…”

Section: Resultscontrasting

confidence: 78%

“…However, the thermal expansion reported by Frisillo & Buljan (1972) is higher than ours by about 12x10 -6 , and that of Dietrich & Arndt (1982) is lower than the present result by roughly an equivalent amount. Therefore, differences in composition do not appear to explain the extreme thermal expansion values of orthoenstatite reported by Frisillo & Buljan (1972) and Dietrich & Arndt (1982), and the reasons for discrepancies between these two studies are not clear. Moreover, the results of Yang & Ghose (1994) indicate that small amounts of iron should have a minimal affect on the thermal expansion of orthoenstatite ( Table 1).…”

Section: Resultscontrasting

confidence: 78%

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Thermal expansion of natural orthoenstatite to 1473 K

Jackson¹,

Palko²,

Andrault³

et al. 2003

ejm

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The volume thermal expansion of powdered natural orthoenstatite [(Mg 0.994 Fe 0.002 Al 0.004) 2 (Si 0.996 Al 0.004) 2 O 6 ] has been measured to 1473 K using energy dispersive synchrotron X-ray diffraction. Over the temperature range examined, the data are consistent with a volume thermal expansion, , that linearly increases with temperature as given by the expression (T) = 29.7(16) x 10-6 K-1 + 5.7(11) x 10-9 K-2 T. An analysis in terms of the often-used constant expansion coefficient yields 0 = 34.5(17) x 10-6 K-1 , which is in good agreement with several previous experimental results on orthoenstatite (Mg 2 Si 2 O 6) over a similar temperature range. Our results do not support the extreme upper and lower bounds reported in earlier studies for the thermal expansivity of Fe-rich orthoenstatite, but rather suggest that the thermal expansion of this phase is approximately midway between those extreme values.

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Section: Resultscontrasting

confidence: 88%

Section: Resultscontrasting

confidence: 78%

Section: Resultscontrasting

confidence: 78%

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Thermal expansion of natural orthoenstatite to 1473 K

Jackson¹,

Palko²,

Andrault³

et al. 2003

ejm

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“…generally included. We have used parameters of either forsterite [Skinner, 1962;Kurnazawa and Anderson, 1969] or of bronzite [Frisi!lo and Barsch, 1972;Frisillo and Buljan, 1972] though generally the forsterite values will be employed below.…”

Section: The Moment Of Inertia Of the Moon Can Be Calculated Frommentioning

confidence: 99%

Structure of the Moon

Toksöz

Dainty

Solomon

et al. 1974

Reviews of Geophysics

227

139

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Seismic data from the four stations of the Apollo passive seismic network have been analyzed to obtain the velocity structure of the moon. The long reverberating train of seismic energy observed in lunar seismograms may be explained by scattering in a near‐surface zone. The earliest parts of the seismogram correspond to body wave phases and may be interpreted by conventional methods. There are no clearly identifiable dispersed surface wave trains present on lunar seismograms. This absence can be explained by scattering of surface waves by near‐surface heterogeneities. Analysis of body wave phases from artificial impacts of known impact time and position yields a crustal section. In the Mare Cognitum region the crust is about 60 km thick and is layered. In the 20‐km‐thick upper layer, velocity gradients are high and microcracks may play an important role. The 40‐km‐thick lower layer has a nearly constant 6.8‐km/s velocity. There may be a thin high‐velocity layer present beneath the crust. The determination of seismic velocities in the lunar mantle is attempted by using natural impacts and deep moonquakes. The simplest model that can be proposed for the mantle consists of a ‘lithosphere’ overlying an ‘asthenosphere.’ Shear waves are attenuated in the ‘asthenosphere,’ and this zone may be partially molten. No seismic data contradict this model. The best value for the compressional wave velocity of the lithosphere is 8.0 → 8.3 km/s, but this may be an average over several differing regions. Density models are calculated for the moon by using the latest value for the moment of inertia (C/MR² = 0.395±0.005), mean density, and temperature and pressure dependence of density for likely lunar models. The mean density in the lunar mantle, corrected to standard (surface temperature, zero pressure) conditions, is 3.4–3.5 g/cm³. These values together with the mean compressional wave velocities are consistent with an olivine‐pyroxene (olivine‐rich) lunar mantle but do not exclude other compositions. On the basis of the density models, some limitations can be placed on the maximum allowable radius of an iron‐rich lunar core. If the lunar mantle is chemically and mineralogically homogeneous, the maximum radius of such a core is about 700 km for an FeS composition and about 450 km for pure Fe composition. There are no geophysical data that indicate whether the moon does or does not have an iron‐rich core.

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“…For opx, α T ≈ 0.16 10 −4 /℃, irrespective of its composition (Frisillo and Buljan 1972;Sueno, et al 1976) and α P ≈ −3.5 10 −3 / GPa (Angel and Hugh-Jones (1994) for enstatite). For cpx, α T ≈ 0.06 10 −4 /℃ (Cameron, et al (1973) for either hedenbergite of diopside) and α P ≈ −2.8 10 −3 /GPa (Levien and Prewitt (1981) for diopside).…”

Section: -Appendixmentioning

confidence: 99%

Crystal bending, subgrain boundary development, and recrystallization in orthopyroxene during granulite-facies deformation

Raimbourg¹,

Kogure

Toyoshima

2011

Contrib Mineral Petrol

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International audienceA prominent feature of a granulite-facies shear zone from the Hidaka Main Zone (Japan) is the folding of orthopyroxene (opx) porphyroclasts. Dislocation density estimated by transmission electron microscope (TEM) and chemical etching in homogeneously folded domains is too low to account for the amplitude of crystallographic bending, leading us to propose a model similar to "flexural slip" folding, where folded layers are micrometer-wide opx layers between thin planar clinopyroxene (cpx) exsolutions. Extension (compression) in the extrados (intrados) of the folded layer is accommodated by dislocations at the cpx-opx interfaces. Alternatively to distributed deformation, crystal bending also localizes in grain boundaries (GBs), mostly oriented close to the (001) plane and with various misorientation angles but misorientation axes consistently close to the b-axis. For misorientation up to a few degrees, GBs were imaged as tilt walls composed of regularly spaced (100)[001] dislocations. For misorientation angles of 7°, individual dislocations are no longer visible, but high-resolution TEM (HRTEM) observation showed the partial continuity of opx tetrahedral chains through the boundary. For 21° misorientation, the two adjacent crystals are completely separated by an incoherent boundary. In spite of these atomic-scale variations, all GBs share orientation and rotation axis, suggesting a continuous process of misorientation by symmetric incorporation of (100)[001] dislocations. In addition to the dominant GBs perpendicular to the (100) plane, boundaries at low angle with (100) planes are also present, incorporating dislocations with a component of Burgers vector along the a-axis. The two kinds of boundaries combine to delimit subgrains, which progressively rotate with respect to host grains around the b-axis, eventually leading to recrystallization of large porphyroclasts

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Linear thermal expansion coefficients of orthopyroxene to 1000°C

Cited by 69 publications

References 3 publications

Thermal expansion of natural orthoenstatite to 1473 K

Thermal expansion of natural orthoenstatite to 1473 K

Structure of the Moon

Crystal bending, subgrain boundary development, and recrystallization in orthopyroxene during granulite-facies deformation

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