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Microthermometry and Raman spectroscopy of fluid inclusions from El Vapor gold mineralizations, Colombia
摘要： Epigenetic El Vapor gold mineralization is hosted by the Segovia batholith and sedimentary rocks at both sides of El Nús fault, in the eastern flank of the Colombian Andes central cordillera. Gold mineralization is composed by continuous and discontinuous sigmoidal and stockwork veins and veinlets from a few centimeters to two meters of thickness and by hydrothermal breccias. Ore mineralogy includes Pyrite + Galena + Sphalerite + Chalcopyrite + Pyrrhotite + Proustite - Pyrargyrite. Gold occurs as inclusions within pyrite, between quartz crystals and filling fractures within pyrite at a late stage of mineralization. The fluid inclusions in quartz veins occur as clusters of primary inclusions or in alignments of secondary and pseudo-secondary inclusions. Based on petrography and Raman spectroscopy, four types of fluid inclusions could be recognized: (1) Type I are primary biphasic, liquid-rich, with CO2(v) + N2(v) + CH4(v) + KCl(AQ) + NaCl(AQ) + H2O(L), (2) Type II are primary or pseudo-secondary, multi-volatile presenting CO2(V) + CO2(L) + N2(V) + CH4(V) + KCl(AQ) + NaCl(AQ) + H2O(L), (3) Type III are secondary, two-phase, liquid-rich inclusions, composed of H2O(v) + H2O(L) + KCl(AQ) + NaCl(AQ) and have two different times of formation (IIIA and IIIB), (4) Type IV are very rare, three-phasic, secondary inclusions and composed of S + H2O(V) + H2O(L) + KCl(AQ) + NaCl(AQ). The microthermometric and spectroscopic analysis of fluid inclusions indicates that the fluid associated with the first event of mineralization identified in El Vapor have low to moderate salinities (3.5-9.2 wt% NaCl equiv.), with trapping temperatures between 214°C and 350°C and pressures between 0.5kbar and 2.9kbar. Due to the nonexistence of fluid inclusions with variable degree of filling with opposite homogenization and because of the variations of salinity in a restricted homogenization temperatures range, it is proposed an isothermal fluid mixture process, which together with fO2 changes, generated by fluid reaction with the carbonaceous shales of the Segovia sedimentary rocks, could influence the process of gold deposition. Hydrothermal fluids from El Vapor were near neutral and reduced; simlar features have been found in orogenic deposits hosted by turbidite sequences around the world.
关键词： Orogenic,reduced fluids,El Vapor district,Microthermometry,Raman spectroscopy,Gold mineralizations,Fluid inclusions
更新于2025-09-23 15:23:52
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Filler metal distribution and processing stability in laser-arc hybrid welding of thick HSLA steel
摘要： Welds made by high power laser beam have deep and narrow geometry. Addition of filler wire by the arc source, forming the laser-arc hybrid welding (LAHW) process, is very important to obtain required mechanical properties. Distribution of molten wire throughout the entire weld depth is of concern since it tends to have low transportation ability to the root. Accurate identification of filler metal distribution is very challenging. Metal-cored wires can provide high density of non-metallic inclusions (NMIs) which are important for acicular ferrite nucleation. Accurate filler distribution can be recognized based on statistical characterization of NMIs in the weld. In the present study, it was found that the amount of filler metal decreased linearly towards the root. The filler metal tends to accumulate in the upper part of the weld and has a steep decrease at 45–55 % depth which also has wavy pattern based on longitudinal cuts. Substantial hardness variation in longitudinal direction was observed, where in the root values can reach > 300 HV. Excessive porosity was generated at 75 % depth due to unstable and turbulent melt flow based on morphology of prior austenite grains. The delicate balance of process parameters is important factor for both process stability and filler metal distribution.
关键词： Filler metal distribution,Microstructure,Thick steel,Non-metallic inclusions,High strength steel,Mechanical properties,Laser-arc hybrid welding
更新于2025-09-23 15:19:57
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Advantages and Limitations of Laser-Assisted Mass Spectrometry for the Local Determination of the Trace Element Composition of Fluid Inclusions in Quarzites in the Bural-Sardyk Deposit (Vostochny Sayan, Buryatia)
摘要： The effect of laser radiation on the surface and volume of natural quartz of the Bural-Sardyk deposit (East Sayan, Buryatia) is studied. The influence of the main parameters of laser radiation with a wavelength of 213 nm (prefix NWR-213) and the properties of the sample on the results of elemental mass spectrometric analysis with inductively coupled plasma are established. The features of laser ablation of various microinclusions in quartz are considered. The main problems arising from the laser evaporation of fluid inclusions in quartzites for the quantitative determination of their chemical composition are indicated.
关键词： superquartzite,fluid inclusions,LA-ICP-MS,inductively coupled plasma mass spectrometry,laser ablation,quartz
更新于2025-09-23 15:19:57
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Light Metals 2016 (TMS/Light) || TiB <sub/>2</sub> Particle Detection in Liquid Aluminum via Laser Induced Breakdown Spectroscopy
摘要： Experimental Because aluminum alloy castings are becoming commonplace for critical applications in the automotive and aerospace industries, tight control over the cleanliness of the melt (mitigation of solid particle inclusions) and microstructure must be achieved. In order to control cleanliness, it must first be well defined and measured. Very few techniques exist in industry that can quantitatively measure in-situ. Laser-induced breakdown spectroscopy (LIBS) is presented as a promising technique to quantify solid particles, desired or undesired, in aluminum melts. By performing LIBS with subsequent statistical analysis on liquid Al with varying amounts of TiB2 particles, calibration curves for B and Ti were generated.
关键词： Inclusions,LIBS,Metal Cleanliness,Liquid Aluminum
更新于2025-09-12 10:27:22
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Light Metals 2015 (Hyland/Light) || SiC Particle Detection in Liquid Aluminum via Laser Induced Breakdown Spectroscopy
摘要： Aluminum alloy castings are becoming commonplace for critical applications in the automotive and aerospace industries where materials failure is not an option. Tight control over cleanliness of the melt (mitigation of solid particle inclusions and dissolved gases) and microstructure must be achieved. Very few techniques exist that can quantitatively measure inclusion levels in-situ. The use of laser-induced breakdown spectroscopy (LIBS) has shown promise as a technique to quantify solid particles, wanted and unwanted, in aluminum melts. SiC particles were added to pure aluminum and analyzed with LIBS, and traditional metallography. An algorithm, based on the Nalimov test, was used to differentiate between LIBS signal from the matrix and particles. Initial tests show a linear relationship between SiC concentration and LIBS signal.
关键词： Inclusions,LIBS,Metal Cleanliness,Liquid Aluminum
更新于2025-09-11 14:15:04