Synthetic fluid inclusions. XV. TEM investigation of plastic flow associated with reequilibration of fluid inclusions in natural quartz   总被引：1，自引：0，他引：1  

Maxim O. Vityk  Robert J. Bodnar  Jean-Claude Doukhan 《Contributions to Mineralogy and Petrology》2000,139(3):285-297

The nature and abundance of dislocations in quartz surrounding fluid inclusions were studied to obtain a better understanding of processes associated with fluid inclusion reequilibration. Synthetic fluid inclusions containing 10 wt% NaCl aqueous solution were formed in three samples at 700 °C and 5 kbar. One of the samples was quenched along an isochore to serve as a reference sample. The other two samples were quenched along a P-T path that generated internal pressures in excess of the confining pressure. The two samples were held at the final reequilibration P-T conditions of 625 °C and 2 kbar for 30 and 180 days, respectively. Following the experiments, microstructures associated with fluid inclusions were examined with the TEM. Quartz in healed fractures in the reference sample that was quenched isochorically shows a moderate dislocation activity. Quartz adjacent to reequilibrated fluid inclusions in the other two samples, however, showed a marked increase in dislocation activity compared to the un-reequilibrated sample. Deformation of the inclusion walls occurred anisotropically by expansion of mobile dislocations in their slip systems. Dislocation expansion was controlled by glide in the rhombohedral planes {1 0 1 1} that was restricted to narrow zones (≤3 μm) in the immediate vicinity of the fluid inclusion walls outside of the healed fracture plane. These plastic zones were observed after both short term (30 days) and long term (180 days) experiments and are attributed to hydrolytic weakening of quartz around fluid inclusions owing to diffusion of water into the quartz matrix during the experiment. The close spatial association of submicroscopic water bubbles with dislocations, and the rarity of water bubbles in the reference sample, show clearly that in both the 30 and 180 day experiments reequilibration involves water loss from the fluid inclusions. Our results indicate that synthetic fluid inclusions in this study recover (chemically and volumetrically), even at relatively fast experimental loading rates, such that internal stresses never reach the point of brittle failure. The driving force for fluid inclusion deformation involves two related mechanisms: plastic deformation of hydrolytically weakened wet quartz in the healed fracture, and water leakage associated with preexisting and strain-induced dislocations. Received: 5 May 1998 / Accepted: 10 February 2000  相似文献   

An experimental study of solid matrix weakening in water‐saturated Savonnières limestone     

Maxim Lebedev  Moyra E.J. Wilson  Vassily Mikhaltsevitch 《Geophysical Prospecting》2014,62(6):1253-1265

Petrophysical properties of carbonate reservoirs are less predictable than that of siliciclastic reservoirs. One of the main reasons for this is the physical and chemical interactions of carbonate rocks with pore fluids. Such interactions can significantly change the elastic properties of the rock matrix and grains, making the applicability of Gassmann's fluid substitution procedure debatable. This study is an attempt to understand the mechanisms of fluid‐rock interactions and the influence of these interactions on elastic parameters of carbonates. We performed precise indentation tests on Savonnières limestone at a microscale level under dry, distilled water, and n‐Decane saturated conditions. Our experiments display softening of the rock matrix after water saturation. We have found that mainly the ooid cortices, peloid nuclei and prismatic intergranular cement are affected by water flooding. We also observed a shear modulus reduction in Savonnières limestone in an experiment performed at ultrasonic frequencies. One of the most important results obtained in our experimental study is that the Gassmann fluid substitution theory might not always be applicable to predict the elastic moduli of fluid‐saturated limestones.  相似文献   

Abrupt transition from fractional crystallization to magma mixing at Gorely volcano (Kamchatka) after caldera collapse     

Maxim Gavrilenko  Alexey Ozerov  Philip R. Kyle  Michael J. Carr  Alex Nikulin  Christopher Vidito  Leonid Danyushevsky 《Bulletin of Volcanology》2016,78(7):47

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Control Volume Method for the Dynamo Problem in the Sphere with the Free Rotating Inner Core     

Hejda  Pavel  Reshetnyak  Maxim 《Studia Geophysica et Geodaetica》2003,47(1):147-159

A model of thermally driven dynamo in the Boussinesq approximation in the spherical shell with the free rotating inner core is considered. To solve equations we use a new in dynamo modeling control volume technique (for details of this method for hydrodynamics see Patankar, 1980). The main advantage of this method over previous attempts to solve magnetohydrodynamics equations in the spherical grids is that no filtering of high harmonics in the pole regions is needed. We present the results of simulations for the self-consistent dynamo system evolution over the diffusion time and longer periods. Different ways of stabilizations of magnetohydrodynamics equations, when convective terms are of the same order (or larger) as conductive ones, are considered.  相似文献   

Gamma-ray bursts from unstable Poynting-dominated outflows     

Maxim Lyutikov  Eric G. Blackman 《Monthly notices of the Royal Astronomical Society》2001,321(2):177-186

Poynting-flux driven outflows from magnetized rotators are a plausible explanation for gamma-ray burst engines. We suggest a new possibility for how such outflows might transfer energy into radiating particles. We argue that, in a region near the rotation axis, the Poynting flux drives non-linearly unstable large-amplitude electromagnetic waves (LAEMW) that 'break' at radii     where the MHD approximation becomes inapplicable. In the 'foaming' (relativistically reconnecting) regions formed during the wave breaks, the random electric fields stochastically accelerate particles to ultrarelativistic energies which then radiate in turbulent electromagnetic fields. The typical energy of the emitted photons is a fraction of the fundamental Compton energy     with     plus additional boosting due to the bulk motion of the medium. The emission properties are similar to synchrotron radiation, with a typical cooling time ∼10⁻³ s. During the wave break, the plasma is also bulk accelerated in the outward radial direction and at larger radii can produce afterglows due to interactions with the external medium. The near equipartition fields required by afterglow models may be due to magnetic field regeneration in the outflowing plasma (similar to field generation by LAEMW in laser–plasma interactions) and mixing with the upstream plasma.  相似文献   

Location of hydrogen atoms in hydronium jarosite     

Henry J. Spratt  Maxim Avdeev  Michael C. Pfrunder  John McMurtrie  Llew Rintoul  Wayde N. Martens 《Physics and Chemistry of Minerals》2014,41(7):505-517

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Lagrangian study of transport of subarctic water across the Subpolar Front in the Japan Sea     

Sergey V. Prants  Michael Yu. Uleysky  Maxim V. Budyansky 《Ocean Dynamics》2018,68(6):701-712

The southward near-surface transport of transformed subarctic water across the Subpolar Front in the Japan Sea is simulated and analyzed based on altimeter data from January 1, 1993 to December 31, 2017. Computing Lagrangian indicators for a large number of synthetic particles, advected by the AVISO velocity field, we find preferred transport pathways across the Subpolar Front. The southward transport occurs mainly in the central part of the frontal zone due to suitable dispositions of mesoscale eddies promoting propagation of subarctic water to the south. It is documented with the help of Lagrangian origin and L-maps and verified by the tracks of available drifters. The transport of transformed subarctic water to the south is compared with the transport of transformed subtropical water to the north simulated by Prants et al. (Nonlinear Process Geophys 24(1):89–99, 2017c).  相似文献   

Nano-mechanical Properties and Pore-Scale Characterization of Different Rank Coals   总被引：1，自引：0，他引：1  

Zhang  Yihuai  Lebedev  Maxim  Smith  Gregory  Jing  Yu  Busch  Andreas  Iglauer  Stefan 《Natural Resources Research》2020,29(3):1787-1800

Characterization of coal micro-structure and the associated rock mechanical properties are of key importance for coal seam exploration, coal bed methane development, enhanced coal bed methane production and CO₂ storage in deep coal seams. Considerable knowledge exists about coal chemical properties, but less is known about the nanoscale to the micro-scale structure of coals and how they change with coal strength across coal ranks. Thus, in this study, 3D X-ray micro-computed tomography (with a voxel size of 3.43 µm) and nano-indentation tests were conducted on coal samples of different ranks from peat to anthracite. The micro-structure of peats showed a well-developed pore system with meso- and micro-pores. The meso-pores essentially disappear with increasing rank, whereas the micro-pores persist and then increase past the bituminous rank. The micro-fracture system develops past the peat stage and by sub-bituminous ranks and changes into larger and mature fracture systems at higher ranks. The nano-indentation modulus showed the increasing trend from low- to high-rank coal with a perfect linear relationship with vitrinite reflectance and is highly correlated with carbon content as expected.

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Photosynthetic community responses to upwelling in mesoscale eddies in the subtropical North Atlantic and Pacific Oceans   总被引：1，自引：0，他引：1  

Thomas S. Bibby  Maxim Y. Gorbunov  Kevin W. Wyman  Paul G. Falkowski   《Deep Sea Research Part II: Topical Studies in Oceanography》2008,55(10-13):1310

In this paper we summarise the photo-physiological responses of phytoplankton to upwelling of macronutrients in mesoscale eddies in the subtropical North Atlantic (EDDIES project, Sargasso Sea) and subtropical North Pacific (E-FLUX project, Hawaii). The observations, obtained on two sets of cruises over 2 years, occupied six cyclonic eddies and two mode-water eddies. The photosynthetic physiological parameters were measured using a bench-top fluorescence induction and relaxation (FIRe) system and a submersible in situ fast repetition rate fluorometer (FRRF) deployed on an undulating towed vehicle. Both of these instruments were used to provide highly sensitive and well-resolved data on community responses. The responses are dependent on both the type of eddy and its stage of development. Our results indicate that, while cyclonic eddies in the Atlantic and Pacific can increase primary photosynthetic production early in their development, mode-water eddies in the subtropical North Atlantic can support patchy blooms of large diatoms for long periods of time (more than 3 months).  相似文献