Poisson's ratios of crystalline rocks as a function of hydrostatic confining pressure

Wang, Qian; Ji, Shaocheng

doi:10.1029/2008jb006167

Cited by 40 publications

(47 citation statements)

References 77 publications

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“…For gouge samples, dynamic Young's moduli and Poisson ratios are between 26 to 46 GPa and 0.16 to 0.30. These values are in the range of values obtained from boreholes and laboratory measurements comprised between 10 GPa to 80 GPa and 0.1 to 0.3, respectively [ Faulkner et al ., ; Wang and Ji , ; Jeppson et al ., ; Blake et al ., ].…”

Section: Resultssupporting

confidence: 89%

Development and maintenance of fluid overpressures in crustal fault zones by elastic compaction and implications for earthquake swarms

et al. 2015

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The ability of crustal faults to compact and to pressurize pore fluids is examined by combining geological observations, petrophysical measurements (permeability, P and S wave velocities, and porosity), and fully coupled hydromechanical modeling. A strike-slip fault located in the Argentera-Mercantour crystalline massif (southwestern French-Italian Alps) was analyzed in the field. This mature fault belongs to a large active fault system characterized by a recurrent seismic swarm activity (M w < 4) between 2 and 12 km depth. The studied exposure corresponds to a 50 m thick anastomosing fault composed of three types of rock: host-rock gneiss, damage-zone phyllonite, and core zone gouge. Laboratory measurements made at effective pressures ranging from 10 to 190 MPa show that the studied fault differs from the classical model and has a high-porosity, high-permeability, and low-rigidity core zone surrounded by a low-porosity, low-permeability, and high-rigidity damage zone with respect to the host rock. The hydraulic and elastic properties are controlled by different microstructures such as foliation, microcracks, and pores developed during the exhumation history of the massif and the reactivation of inherited low-friction mylonitic foliation. Hydromechanical modeling is then used to investigate the spatio-temporal evolution of the fluid overpressures across the fault zone elements in response to elastic compaction. Models demonstrate that fluid pressure can be developed and maintained temporally in the studied fault zone. This study concludes on the key role played by the hydromechanical properties of faults during compaction and provides an explanation for seismic swarm triggering and maintenance.

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Section: Resultssupporting

confidence: 89%

Development and maintenance of fluid overpressures in crustal fault zones by elastic compaction and implications for earthquake swarms

et al. 2015

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“…High‐pressure velocity measurements using standard pulse transmission methods [ Birch , ] were carried out at the Geological Survey of Canada/Dalhousie High Pressure Laboratory in Halifax, Nova Scotia [ Ji et al ., ; Wang and Ji , ; Sun et al ., ]. Three cylindrical minicores, 2.54 cm in diameter and 5–7 cm in length, were cut in the X, Y, and Z directions of each sample except sample AM1 from which seven minicores were taken in order to constrain the geometry of seismic anisotropy.…”

Section: Measured Seismic Velocities and Anisotropymentioning

confidence: 99%

A new calibration of seismic velocities, anisotropy, fabrics, and elastic moduli of amphibole‐rich rocks

Shao

Michibayashi

et al. 2013

JGR Solid Earth

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A large portion of the middle to lower crust beneath the continents and oceanic island arcs consists of amphibolites dominated by hornblende and plagioclase. We have measured P and S wave velocities (Vp and Vs) and anisotropy of 17 amphibole‐rich rock samples containing 34–80 vol % amphibole at hydrostatic pressures (P) up to 650 MPa. Combined petrophysical and geochemical analyses provide a new calibration for mean density, average major element contents, mean Vp‐P and Vs‐P coefficients, intrinsic Vp and Vs anisotropy, Poisson's ratios, the logarithmic ratio Rs/p, and elastic moduli of amphibole‐rich rocks. The Vp values decrease with increasing SiO2 and Na2O + K2O contents but increase with increasing MgO and CaO contents. The maximum (≤0.38–0.40 km/s) and minimum S wave birefringence values occur generally in the propagation direction parallel to Y and normal to foliation, respectively. Amphibole plays a critical role in the formation of seismic anisotropy, whereas the presence of plagioclase, quartz, pyroxene, and garnet diminishes the anisotropy induced by amphibole crystallographic preferred orientations (CPOs). The CPO variations cause different anisotropy patterns illustrated in the Flinn diagram of Vp(X)/Vp(Y)‐Vp(Y)/Vp(Z) plots. The results make it possible to distinguish, in terms of seismic properties, the amphibolites from other categories of lithology such as granite‐granodiorite, diorite, gabbro‐diabase, felsic gneiss, mafic gneiss, eclogite, and peridotite within the Earth's crust. Hence, amphibole, aligned by dislocation creep, anisotropic growth, or rigid‐body rotation, is the most important contributor to the seismic anisotropy of the deep crust beneath the continents and oceanic island arcs, which contains rather little phyllosilicates such as mica or chlorite.

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“…For each sample, λ and μ as a function of pressure or temperature were calculated. In this database, 87 samples were measured by our group: 57 from the Dabie‐Sulu ultrahigh pressure metamorphic terrane and 20 from the Yunkai Mountains of China [ Wang et al , 2005a, 2005b; Ji et al , 2007; Wang and Ji , 2009], and 10 from the Tantato high grade metamorphic domain in northern Saskatchewan, Canada [ Ji and Salisbury , 1993; Ji et al , 1993]. The literature data were taken from Ji et al [2002, and references therein].…”

Section: Data For Analysismentioning

confidence: 99%

Lamé parameters of common rocks in the Earth's crust and upper mantle

Sun

Wang

et al. 2010

J. Geophys. Res.

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[1] Lamé parameter (l) and shear modulus (m) are the most important, intrinsic, elastic properties of rocks. The Lamé parameter l, which relates stresses and strains in perpendicular directions, is closely related to the incompressibility and contains a high proportion of information about the resistance to a change in volume caused by a change in pressure. Recent studies have emphasized the roles played by l in the discrimination of gas sands from carbonates and shale in sedimentary basins and in the seismic reflection of crustal fault zones. Here we analyze the equivalent isotropic elastic data of 475 natural rocks in order to characterize l values for common types of crystalline rocks in the Earth's crust and upper mantle and their variations with pressure (P), temperature (T), and mineralogical composition. When no partial melting, metamorphic reaction, dehydration, or phase transformation occurs, l of a crystalline rock as a function of P and T can be described by l = a + (dl/dP)P − c exp(− kP) − (dl/dT)T, where a is the projected l value at zero pressure if microcracks were fully closed; dl/dP is the pressure derivative in the linear elastic regime; c is the initial l drop caused by the presence of microcracks at zero pressure; k is a decay constant of the l drop in the nonlinear poroelastic regime; and dl/dT is the temperature derivative. The parameter l increases nonlinearly and linearly with increasing pressure at low (<∼300 MPa) and high (>∼300 MPa) pressures, respectively. In the regime of high pressures, l decreases quasi-linearly with increasing temperature with dl/dT values in the range of 1-10 × 10 −3 GPa/°C. Approaching the a-b quartz transition temperature, quartzite displays negative l values. In the l-r (density) and m-l plots, the main categories of lithology can be clearly distinguished. The ultramafic rocks display systematic decreases in both m and l with increasing the degree of serpentinization. Eclogites, mafic rocks (gabbro, diabase, mafic granulite, and mafic gneiss), and felsic rocks (granite, diorite, felsic gneiss, intermediate gneiss, and metasediments) are characterized by high, moderate, and low m and l values, respectively. For pyroxene and olivine, both l and r increase, but m decreases with increasing the Fe/Mg ratios. In the plagioclase series, both l and m increases with increasing the anorthite content. Increases in the contents of garnets, sillimanite, rutile, zircon, ilmenite, and spinel result systematically in an increase in rock's l and m values. The present results provide improved constraints on the discrimination of composition for crustal and upper mantle rocks in terms of l and m.

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Poisson's ratios of crystalline rocks as a function of hydrostatic confining pressure

Cited by 40 publications

References 77 publications

Development and maintenance of fluid overpressures in crustal fault zones by elastic compaction and implications for earthquake swarms

Development and maintenance of fluid overpressures in crustal fault zones by elastic compaction and implications for earthquake swarms

A new calibration of seismic velocities, anisotropy, fabrics, and elastic moduli of amphibole‐rich rocks

Lamé parameters of common rocks in the Earth's crust and upper mantle

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