Steady-State flow in polycrystalline halite at pressure of 2 kilobars
15 Mar 2013-Vol. 16, pp 191-209
About: The article was published on 2013-03-15. It has received 145 citations till now. The article focuses on the topics: Halite.
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TL;DR: In this paper, it was shown that mechanically weak zones (σ 1 − σ 3 <10 MPa) at upper-, mid-and lower crustal depths, inferred from geological and geophysical observations and interpretations, is supported by empirically-determined steady-state flow properties of some common crystalline rocks.
762 citations
TL;DR: In this paper, the reaction reversals to within 0.2 kbar locate the quartz ⇆ coesite equilibrium at 24.6, 24.9, 25.5, 26.2, 27.0, 28.8, and 29.7 kbar at 350, 400, 500, 600, 700, 800, 900, and 1000°C, respectively.
Abstract: Reaction reversals to within 0.2 kbar locate the quartz ⇆ coesite equilibrium at 24.6, 24.9, 25.5, 26.2, 27.0, 27.9, 28.8, and 29.7 kbar at 350, 400, 500, 600, 700, 800, 900, and 1000°C, respectively, using well-calibrated (frictionless), 2.54-cm diameter NaCl furnace assemblies in piston-cylinder apparatus. The equilibrium is unaffected by the presence of H2O or jadeite, contrary to previous proposals. The positive dP/dT of the reaction at T < 500°C is inconsistent with existing thermochemical data for coesite. Numerous tight reversals provide a sound basis for use of the quartz ⇆ coesite equilibrium as a calibration of pressure in high-pressure apparatus.
492 citations
442 citations
TL;DR: In this article, it was shown that dynamic similarity of non-Newtonian flows at low inertia can only be achieved if the steady-state flow curves of the model materials and the various rocks in the prototype have mutually similar shapes and slopes, and if these flows operate on similar parts of their respective flow curves.
361 citations
TL;DR: In this article, a curve separates the two domains in the σ, T plane and moves to higher temperatures and stresses for crystals of higher impurity content; for natural crystals, only rotation recrystallization can occur.
Abstract: Single crystals of pure and impure halite have been dynamically recrystallized during compression creep at temperatures between 250° and 790°C and stresses between 1.5 and 120 bars. Recrystallization was found to occur by two different mechanisms: at lower temperatures and stresses the new grains result from the rotation of subgrains without grain boundary migration (rotation recrystallization), and at higher temperatures and stresses the final texture results from the migration of the high-angle grain boundaries of the rotated subgrains. Migration recrystallization was shown to occur for critical stress and temperature conditions, allowing rapid grain boundary migration. A curve separates the two domains in the σ, T plane and moves to higher temperatures and stresses for crystals of higher impurity content; for natural crystals, only rotation recrystallization can occur. In each recrystallization regime the recrystallized grain size is uniquely related to the applied stress, thus yielding two different geopiezometers, which should not be applied indiscriminately to natural tectonites to determine lithospheric or mantle deviatoric stresses. The experimental results are interpreted by the Lucke et Stuwe theory for impurity-controlled grain boundary migration.
343 citations
References
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01 May 1952
TL;DR: The connection between the elastic behavior of an aggregate and a single crystal is considered in this article, with special reference to the theories of Voigt, Reuss, and Huber and Schmid.
Abstract: The connection between the elastic behaviour of an aggregate and a single crystal is considered, with special reference to the theories of Voigt, Reuss, and Huber and Schmid. The elastic limit under various stress systems is also considered, in particular, it is shown that the tensile elastic limit of a face-centred aggregate cannot exceed two-thirds of the stress at which pronounced plastic distortion occurs.
7,944 citations
TL;DR: In this paper, an elementary account of several theoretical methods of attack is given, among them the derivation of inequalities between various moduli, and the approach is completely general and exact.
Abstract: The title problem concerns two isotropic phases firmly bonded together to form a mixture with any concentrations. An elementary account of several theoretical methods of attack is given, among them the derivation of inequalities between various moduli. The approach is completely general and exact. Additionally, the problem is fully solved when the phases have equal rigidities but different compressibilities, the geometry being entirely arbitrary.
4,141 citations
TL;DR: In this article, it is suggested that mosaic boundaries and boundaries between grains of nearly the same orientation may not serve as sources or sinks of the diffusion currents, in which case the creep rate will depend only on the configuration of grain boundaries having a sizable orientation differen...
Abstract: According to a suggestion of Nabarro, any crystal can change its shape by self‐diffusion in such way as to yield to an applied shearing stress, and this can cause the macroscopic behavior of a polycrystalline solid to be like that of a viscous fluid. It is possible that this phenomenon is the predominant cause of creep at very high temperatures and very low stresses, though not under more usual conditions. The theory underlying it is developed quantitatively, and calculations of rate of creep, or equivalently of effective viscosity, are given for aggregates of quasi‐spherical grains and for wires composed of cylindrical grains. Allowance is made for the effect of tangential stress relaxation at the grain boundaries. It is suggested that mosaic boundaries and boundaries between grains of nearly the same orientation may be unable to serve as sources or sinks of the diffusion currents, in which case the creep rate will depend only on the configuration of grain boundaries having a sizable orientation differen...
2,214 citations