scholarly journals Preliminary data for melt inclusions in garnet porphyroblasts from Ograzhden metapelites, SW Bulgaria

2020 ◽  
Vol 81 (3) ◽  
pp. 84-86
Author(s):  
Lyubomira Macheva
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Melt Inclusions ◽  
High Grade ◽  
Crystal Shape ◽  
Garnet Porphyroblasts ◽  
High Pressure Metamorphism ◽  
Micro Raman Spectroscopy ◽  
Negative Crystal ◽  
Crystallographic Orientations

Micro-inclusions in garnet porphyroblasts from high-grade Ograzhden metapelites, SW Bulgaria, have been studied by SEM and micro-Raman Spectroscopy. Micro-inclusions are presented by single grains with facetted outlines parallel to rational crystallographic orientations of the host garnet or by multiphase aggregates with negative crystal shape. Many of studied micro-inclusions can be formed by the presence of melt. The morphology of some of them suggests formation under high pressure metamorphism.

scholarly journals Formation Mechanism of the Velyka Vyska Syenite Massif (Korsun-Novomyrhorod Pluton, Ukrainian Shield) Derived from Melt Inclusions in Zircon

2021 ◽  
Vol 43 (1) ◽  
pp. 3-15
Author(s):  
D.K. VOZNYAK ◽  
E.V. ., LEVASHOVA ◽  
S.G. SKUBLOV ◽  
S.G. KRYVDIK ◽  
O.A. VYSHNEVSKYI ◽  
...  
Keyword(s):  
High Pressure ◽  
Melt Inclusions ◽  
Ore Deposits ◽  
Partial Replacement ◽  
Type I ◽  
High Grade ◽  
Ree Distribution ◽  
The Matrix ◽  
Homogenization Temperatures ◽  
Primary Melt

The formation of leucosyenites in the Velyka Vyska syenite massif was provoked by the liquation layering of magmatic melt. This assumption is based on the presence of two primary melt inclusions of different chemical composition in zircon crystals from Velyka Vyska leucosyenites. They correspond to two types of silicate melts. Type I is a leucosyenite type that contains high SiO2 concentrations (these inclusions dominate quantitatively); type II is a melanosyenite type that contains elevated Fe and smaller SiO2 concentrations. The liquation layering of magmatic melt was slow because the liquates are similar in density; leucosyenite melt, which is more abundant than melt of melanosyenite composition, displays greater dynamic viscosity; the initial sizes of embryos of melanosyenite composition are microscopic. Sulphide melt, similar in composition to pyrrhotite, was also involved in the formation of the massif. Zircon was crystallized at temperatures over 1300°С, as indicated by the homogenization temperatures of primary melt inclusions. The REE distribution spectra of the main parts (or zones,) of zircon crystals from the Velyka Vyska massif are identical to those of zircon from the Azov and Yastrubets syenite massifs with which high-grade Zr and REE (Azov and Yastrubets) ore deposits are associated. They are characteristic of magmatically generated zircon. Some of the grains analyzed contain rims that are contrasting against the matrix of a crystal, look dark-grey in the BSE image and display flattened REE distribution spectra. Such spectra are also typical of baddeleyite, which formed by the partial replacement of zircon crystals. The formation of a dark-grey rim in zircon and baddeleyite is attributed to the strong effect of high-pressure СО2-fluid on the rock. The formation patterns of the Velyka Vyska and Azov massifs exhibit some common features: (а) silicate melt liquation; (b) high ZrO2 concentrations in glasses from hardened primary melt inclusions; (c) the supply of high-pressure СО2-fluid flows into Velyka Vyska and Azov hard rocks. Similar conditions of formation suggest the occurrence of high-grade Zr and REE ores in the Velyka Vyska syenite massif.

The Use of Micro-Raman Spectroscopy to Monitor High-Pressure High-Temperature Annealing of Ion-Implanted GaN Films

1999 ◽  
Vol 595 ◽  
Author(s):  
M. Kuball ◽  
J.M. Hayes ◽  
T. Suski ◽  
J. Jun ◽  
H.H. Tan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Surface Layer ◽  
High Temperature ◽  
Structural Quality ◽  
High Temperature Annealing ◽  
Micro Raman Spectroscopy ◽  
High Pressure High Temperature ◽  
Different Temperatures ◽  
Ion Implanted

AbstractWe have investigated the high-pressure high-temperature annealing of Mg/P-implanted GaN films using visible and ultraviolet (UV) micro-Raman spectroscopy. The results illustrate the use of Raman spectroscopy to monitor processing of GaN where fast feedback is required. The structural quality and the stress in ion-implanted GaN films was monitored in a 40nm-thin surface layer of the sample as well as averaged over the sample layer thickness. We find the nearly full recovery of the crystalline quality of ion-implanted GaN films after annealing at 1400-1500°C under nitrogen overpressures of 1.5GPa. No significant degradation effects occurred in the GaN surface layer during the annealing. The high nitrogen overpressures proved very effective in preventing the nitrogen out-diffusion from the GaN surface. Stress introduced during the annealing was monitored. Raman spectra of ion-implanted GaN films were investigated at different temperatures and excitation wavelengths to study the GaN phonon density of states.

scholarly journals The Use of Micro-Raman Spectroscopy to Monitor High-Pressure High Temperature Annealing of Ion-Implanted GaN Films

2000 ◽  
Vol 5 (S1) ◽  
pp. 740-746
Author(s):  
M. Kuball ◽  
J.M. Hayes ◽  
T. Suski ◽  
J. Jun ◽  
H.H. Tan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Surface Layer ◽  
High Temperature ◽  
Structural Quality ◽  
High Temperature Annealing ◽  
Micro Raman Spectroscopy ◽  
High Pressure High Temperature ◽  
Different Temperatures ◽  
Ion Implanted

We have investigated the high-pressure high-temperature annealing of Mg/P-implanted GaN films using visible and ultraviolet (UV) micro-Raman spectroscopy. The results illustrate the use of Raman spectroscopy to monitor processing of GaN where fast feedback is required. The structural quality and the stress in ion-implanted GaN films was monitored in a 40nm-thin surface layer of the sample as well as averaged over the sample layer thickness. We find the nearly full recovery of the crystalline quality of ion-implanted GaN films after annealing at 1400-1500°C under nitrogen overpressures of 1.5GPa. No significant degradation effects occurred in the GaN surface layer during the annealing. The high nitrogen overpressures proved very effective in preventing the nitrogen out-diffusion from the GaN surface. Stress introduced during the annealing was monitored. Raman spectra of ion-implanted GaN films were investigated at different temperatures and excitation wavelengths to study the GaN phonon density of states.

High Pressure in situ Micro-Raman Spectroscopy of Ge-Sn System Synthesized in a Laser Heated Diamond Anvil Cell

2011 ◽  
Author(s):  
Y. A. Sorb ◽  
N. Subramanian ◽  
T. R. Ravindran ◽  
P. Ch. Sahu ◽  
Alka B. Garg ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
Micro Raman Spectroscopy ◽  
Diamond Anvil ◽  
Laser Heated

Use of Hardness Indentation Coupled with Micro-Raman Spectroscopy in High-Pressure Materials Research

1997 ◽  
Vol 499 ◽  
Author(s):  
A. Kailer ◽  
Y. G. Gogotsi ◽  
K. G. Nickel
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Phase Transformations ◽  
Materials Science ◽  
High Pressure Phase ◽  
Shear Stresses ◽  
Micro Raman Spectroscopy ◽  
Wide Range ◽  
Mechanical Contacts ◽  
Pressure Phase

ABSTRACTHigh-pressure phase transformations occurring in materials are important for a wide range of problems in materials science and engineering. Most of the results in this field have been obtained using high-pressure cells.In this work, we demonstrate that high-pressure phase transformations also take place during mechanical contact of hard solid materials. These solid-state transformations can be studied by simply combining hardness indentation tests with micro-Raman spectroscopy. In contrast to diamond anvil cell (DAC) experiments, the stress conditions during mechanical contacts are highly non-hydrostatic, i.e. very high shear stresses affect the transformation behavior. Nevertheless, the obtained results can be discussed in the light of the phase transformations as known from DAC experiments. The examples of our research presented here include Si, Ge, SiO2 and ZrO2, and show that phase transformations and amorphization at mechanical contacts are a quite common phenomenon, which has important implications.

scholarly journals A new high-pressure cell for systematic in situ investigations of micro-scale processes in gas hydrates using confocal micro-Raman spectroscopy

2020 ◽  
Vol 91 (11) ◽  
pp. 115103 ◽  
Author(s):  
Judith M. Schicks ◽  
Mengdi Pan ◽  
Ronny Giese ◽  
Mathias Poser ◽  
Nur Aminatulmimi Ismail ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Gas Hydrates ◽  
High Pressure Cell ◽  
Micro Scale ◽  
Micro Raman Spectroscopy ◽  
Pressure Cell

Fabrication and Residual Stresses of Aluminum Nitride Ceramics Sintered at High-Pressure

2009 ◽  
Vol 79-82 ◽  
pp. 2215-2218
Author(s):  
Xiao Lei Li ◽  
Shang Sheng Li ◽  
Hong An Ma ◽  
Xiao Peng Jia
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Residual Stresses ◽  
Aluminum Nitride ◽  
Compression Stress ◽  
Sintering Additives ◽  
Micro Raman Spectroscopy ◽  
Sintering Time ◽  
Nitride Ceramics ◽  
Residual Compression

High-density AlN ceramics were fabricated without sintering additives at high pressure (5.0 GPa) and temperature (1300-1700 °C). The sintered bodies were characterized by XRD and micro-Raman spectroscopy (MRS). The values of residual stresses due to the distortion of the AlN lattice were assessed using the Micro-Raman Spectroscopy (MRS). Residual compression stress of the AlN ceramics sintered at 5.0 GPa and 1700 °C for 125 min is -2.0 GPa. The residual compression stress increased according to the extension of the sintering time.

Beyond ultra-high pressure metamorphism: evidence for extremely high pressure conditions during frictional fusion in gigantic landslides using micro-Raman spectroscopy of quartz: the Tsergo Ri (Langtang Himal, Nepal) rockslide

2021 ◽  
Author(s):  
Peter Tropper ◽  
Kurt Krenn ◽  
Diethard Sanders
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Mass Movement ◽  
Planetary Science ◽  
Raman Mode ◽  
Raman Shift ◽  
Glassy Matrix ◽  
Significant Shift ◽  
Micro Raman Spectroscopy ◽  
Quartz Grains

<p>The Tsergo Ri rockslide represents one of the world's biggest rockslides in crystalline rocks (original volume: 10<sup>10</sup> m<sup>3</sup>). The mass movement comprises migmatites, leucogranites, orthogneisses and paragneisses (Weidinger et al. 2014). During mass-wasting, frictionites and microbreccias formed at the base of the rockslide. The frictionite is mainly composed of a glassy matrix containing biotite, quartz, and abundant plagioclase and K-feldspar. Biotite locally shows a transformation to spinel + glass in highly glassy microdomains. Fe-rich layers in the glass indicate melting of biotite-rich layers of the protolith biotite-bearing orthogneiss. Locally, quartz grains are rimmed by a thin layer of SiO<sub>2</sub> glass (lechatelierite).</p><p>Investigations by McMillan et al. (1991) and Kowitz et al. (2013) have shown that shocked quartz shows a shift in the main A1 Raman mode down to lower wavenumbers with increasing pressures. Tropper et al. (2017) and Sanders et al. (2020) found that quartz from the frictionites in the Köfels landslide (Austria) shows a significant shift of up to 4 cm<sup>-1</sup> in the main A1 Raman mode. Therefore micro-Raman spectroscopy was applied to quartz crystals with and without lechatelierite rims in the Tsergo Ri frictionites. Raman maps of quartz grain areas were prepared using a HORIBA Jobin Yvon LabRam HR800 micro-spectrometer equipped with a 30 mW He-Ne laser (633 nm emission).</p><p>Micro-Raman spectroscopy of 'normal' quartz yielded an intense A1 Raman mode at 464 cm<sup>-1</sup>, whereas<sup>  </sup>quartz without lechatelierite rims shows a shift of this band down to 461.5 cm<sup>-1</sup>. The highest shifts down to 460.5 cm<sup>-1</sup> were observed in quartz grains rimmed by lechatelierite. It is also noteworthy that these grains show an internal gradient of Raman shift of up to 3 cm<sup>-1</sup> from the core (463.5 cm<sup>-1</sup>) to the rim (460.5 cm<sup>-1</sup>) to just below the lechatelierite rims. This is an important observation since lechatelierite formation in frictionites from rockslides was considered so far to be a function of temperature only. Because lechatelierite only rims quartz with strongly shifted A1 band numbers, we interpret lechatelierite formation to be driven by both temperature and pressure, at least under frictionite conditions. The completely molten granitic matrix and the breakdown of biotite to spinel + melt indicates minimum temperatures of 900-1000°C. Sanders et al. (2020) showed that the shifted A1 mode of quartz is stable only below 1100°C, thus giving an upper limit of the temperature range. The observed Raman shift of the A1 mode and the presence of lechatelierite strongly suggest that a pressure of possibly >24-26 GPa was attained (cf. McMillan et al. 1991, Kowitz et al. 2013). The data from Köfels and Tsergo Ri provide the first quantitative estimates of peak pressures during frictionite formation, and show that UHP-modified quartz associated with lechatelierite is common in landslides of silica-rich rocks.</p><p> </p><p> </p><p>References:</p><p>Kowitz et al. 2013: Earth and Planetary Science Letters, 384:17</p><p>McMillan et al. 1992: Physics and Chemistry of Minerals, 19:71</p><p>Sanders et al. 2020: EGU2020-4831</p><p>Tropper et al. 2017: Mitteilungen der Österreichischen Mineralogischen Gesellschaft, 163: 89</p><p>Weidinger et al. 2014: Earth and Planetary Science Letters, 389:62</p>

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