Topic
Quartz inversion
About: Quartz inversion is a research topic. Over the lifetime, 22 publications have been published within this topic receiving 708 citations.
Papers
TL;DR: In this paper, the decrepitation behavior of fluid inclusions in quartz at one atmosphere confining pressure has been evaluated using pure H2O synthetic inclusions formed by healing fractures in natural quartz.
Abstract: The decrepitation behaviour of fluid inclusions in quartz at one atmosphere confining pressure has been evaluated using pure H2O synthetic inclusions formed by healing fractures in natural quartz. Three different modes of non-elastic deformation, referred to as stretching, leakage or partial decrepitation, and total decrepitation have been observed. The internal pressure required to initiate non-elastic deformation is inversely related to inclusion size according to the equation:
internal pressure (kbar) = 4.26 D-0.423
where D is the inclusion diameter in microns. Regularly shaped inclusions require a higher internal pressure to initiate non-elastic deformation than do irregularly shaped inclusions of similar size. Heating inclusions through the α/β quartz inversion results in mechanical instability in the quartz crystal and leads to mass decrepitation of inclusions owing to structural mismatches generated by pressure gradients in the quartz around each inclusion.
Long-term heating experiments (∼2 years) suggest that the internal pressure required to initiate non-elastic deformation does not decrease significantly with time and indicates that short-lived thermal fluctuations in natural systems should not alter the inclusion density and homogenization temperature. Inclusions that do exhibit decreased density (higher homogenization temperature) are, however, always accompanied by a change in shape from irregular to that of a negative crystal.
Observations of this study are consistent with elasticity theory related to fracture generation and propagation around inclusions in minerals. These results indicate that an inclusion will not be influenced by a neighbouring inclusion, or other defect in the host phase, as long as the distance between the two is >2–4 diameters of the larger of the two inclusions.
240 citations
TL;DR: In this article, the high-low quartz inversion temperature has been measured up to 10,000 bars and the relation of change of the inversion with pressure to Earth-structure problems is discussed.
Abstract: The high-low quartz inversion temperature has been measured up to 10,000 bars. The relation of change of the inversion temperature with pressure to Earth-structure problems is discussed. Apparatus which has a working range up to 1400°C and 10,000 bars is described.
143 citations
TL;DR: The physical, mechanical and morphological properties of a rock undergo substantial change when exposed to the extreme temperatures that are encountered in processes such as nuclear waste disposal, underground coal gasification (UCG) and building fires as mentioned in this paper.
Abstract: The physical, mechanical and morphological properties of a rock undergo substantial change when exposed to the extreme temperatures that are encountered in processes such as nuclear waste disposal, underground coal gasification (UCG) and building fires. An attempt has been made in this article to study the different physical and morphological changes that occur within Indian sandstone due to thermal treatment. Tests were performed on a thermally treated air-cooled and non-cooled set of samples in order to observe the change in the physico-morphological properties. Heating has a profound effect on the physical properties such as density, porosity and compression wave velocity (VP), which have been further explained by thin-section, X-ray diffraction (XRD) and scanning electron microscope (SEM) studies. Thermal analyses such as thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were performed to observe the chemical changes occurring in the specimen. Since Dholpur sandstone is a quartz-dominant rock, the thermally induced chemical degradation is minimal in nature. DTA studies revealed the quartz inversion to occur at 579.19 °C. Structural changes that are caused due to the random alignment and the thermal anisotropic behaviour of different minerals lead to microcracking, thereby affecting the physical properties. This study will provide an understanding of the thermal behaviour of rocks and the relationship of the thermal behaviour with physico-mechanical behaviour. The study can prove useful while designing structures in processes such as UCG, nuclear waste disposal, deep mining and geothermal energy; the study can also enable the formation of a protocol to restore the structural integrity and aesthetic value of fire-damaged buildings.
114 citations
TL;DR: In this article, the high-low quartz inversion has been determined over the range 6 to 35 kb by means of differential thermal analysis in piston-cylinder apparatus, with chromel-alumel, Platinel II, and Pt versus Pt + 10% Rh thermocouples.
Abstract: The high-low quartz inversion has been determined over the range 6 to 35 kb by means of differential thermal analysis in piston-cylinder apparatus, with chromel-alumel, Platinel II, and Pt versus Pt + 10% Rh thermocouples. The transition temperature initially rises at the rate of ∼26 deg kb−1; the curvature, - d²T/dp², is less than ∼0.4 deg kb−2, in contrast with the reports of Gibson and of Yoder for the inversion at lower pressures. Comparison with selected data for the quartz-coesite transition suggests an intersection with the high-low quartz inversion near ∼1400°C and ∼37 kb. The several thermodynamic constraints involved if the inversion is first order (and this is not established at present) are discussed in the context of the present results.
103 citations
TL;DR: In this paper, three blocks cut from a single crystal of Brazilian quartz were doped with lithium, sodium, and potassium, respectively, by electrodiffusion at 500°C using a vapor-plated anode of a halide containing the desired alkali ion.
Abstract: The anelastic behavior of natural quartz has been modified by doping with alkali ions. Three blocks cut from a single crystal of Brazilian quartz were doped with lithium, sodium, and potassium, respectively, by electrodiffusion at 500°C using a vapor‐plated anode of a halide containing the desired alkali ion. Fundamental 1‐Mc/sec, AT‐cut shear mode resonators were fabricated from each block. Measurements of Q−1 and resonant frequency were made from liquid‐helium temperatures to near the quartz inversion point at 573°C. For a resonant frequency of 5 Mc/sec internal friction peaks were evident in the low‐temperature region with sodium doping giving peaks at 50° and 140°K, lithium a peak near 100°K, and potassium a peak near 200°K. The activation energies ranged from 0.06 to 0.2 eV and the relaxation times were all the order of 10−12 sec. The low‐temperature behavior induced by sodium doping is of special interest since it is identical to that of certain synthetic quartz crystals. All three doped samples exh...
61 citations
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Performance Metrics
| Year | Papers |
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| 2021 | 1 |
| 2020 | 1 |
| 2019 | 1 |
| 2018 | 1 |
| 2017 | 1 |
| 2016 | 1 |