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Comparison of Raman spectra of a NaCl-rich glass (a) and a microcrystalline mixture of ice and hydrohalite (b) at-190°C.
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A combination of Raman spectrometry and microthermometry has been applied to synthetic fluid inclusions filled with pure H 2 O, a NaCl brine and a MgCl 2 brine, in order to analyze spectra between –190° and +100°C. The combined technique allows: (1) the determination of the types of dissolved salts from the presence of salt hydrates at low temperat...
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This article presents the results of study of fluid inclusions in calcite and quartz of the Devonian, Carboniferous and Permian strata of the eastern part of the Precaspian syneclise and the Aktobe Preuralie of Pre-Ural trough. Were determined by microthermometry method the temperatures of melting and homogenization of fluids in crystals of rock an...
The magmatic fluid phase immiscibility between salt-, silicate-, and Fe-S-O melts from Miocene porphyry Cu-Au-(Mo) deposits from Metaliferi Mountains and Eastern Carpathians in Romania is characterized based on ultrahigh temperature microthermometry (i.e. ≥ 900 o -1100°C) and petrography of the fluid and melt inclusions assemblages, and was describ...
The petrographic characteristics of fluid inclusions of the main gas-bearing intervals of the Upper Paleozoic in the Ordos Basin are analyzed by means of plane-polarized light, fluorescence microscopy, and microthermometry. With the burial history of the basin, the charging and enrichment of natural gas in low-permeability reservoirs are also studi...
Citations
... Raman spectrometry is used to study fluid inclusions (Orange et al., 1996;Zhang et al., 2007;Bourdet et al., 2010;Verma et al., 2012) and to identify gas composition (Zhao et al., 2019). North-Ostaninsk fluid inclusions within 3, 5 and 7 were analyzed for the peak positions and compared with already compiled tables for the most common substances (Samson and Walker, 2000;Bakker, 2004). Raman spectrogram shows a very weak structural organization of the carbonaceous material (Krasnoshchekova et al., 2019) (Fig. 8). ...
Paleozoic rocks in Western Siberia may contain significant hydrocarbon resources. However, effective methods for their exploration are poorly constrained. This study provides new insights into the causes of reservoir formation using the upper part of the Paleozoic succession of the North-Ostaninsk field in the Nyurolsk Basin as a case study. The carbonate rocks have been affected by dolomitization. Four dolomite generations have been identified: Floating in the matrix (D1), fracture-filling (D2.1), stylolite-associated (D2.2), partly replacive (D3) and, pervasive (D4). The last one replaces biogenic limestone in the upper part of the Paleozoic succession and coincides with the presence of a reservoir in the field. A systematic analysis petrographic, fluid inclusion, and carbon and oxygen isotope investigations suggest that the origin of dolomite is from the downward infiltration of meteoric water with higher Mg2+ and Fe2+ derived from the alteration of tuffaceous materials. The results, along with values of the magnetic field anomaly, reveal the relationship between dolomitization and the distribution of the oil and gas reserves in this Paleozoic succession within the basement of the West Siberian Basin. This new insight may be used to predict similar accumulations in poorly explored territories.
... The composition of representative individual inclusions was determined using Raman spectroscopy at room temperature and at cryogenic temperatures (Bakker, 2004;Bodnar, 2003;Goldstein & Reynolds, 1994;Samson & Walker, 2000; see Supplementary Materials for further details). Raman analyses were performed at the University of Innsbruck with a Horiba Jobin-Yvon Labram-HR800 spectrometer, equipped with a 532.18 nm laser and a Linkam THMS600 heating/freezing stage. ...
... Such spectroscopic determinations are consistent with the lack of microthermometric evidence of a carbonic phase or clathrate formation during the freezing experiments (Dubessy et al., 2001;Marchesini et al., 2019). Raman spectra were also acquired at −170 and −100°C, as well as at any observed phase transitions to detect the presence of ice, hydrohalite and salts in the spectral range of 2700 to 3550 cm −1 (Bakker, 2004;Baumgartner & Bakker, 2010;Samson & Walker, 2000). Most of the frozen inclusions showed Raman spectra with poorly defined peaks. ...
Hypogene dissolution‐precipitation processes strongly affect petrophysical properties of carbonate rocks and fluid migration pathways in sedimentary basins. In many deep carbonate reservoirs, hypogene cavernous voids are often associated with silicified horizons. The diagenesis of silica in carbonate sequences is still a poorly‐investigated research topic. Studies exploring the complexity of silica dissolution‐precipitation patterns in hypogene cave analogues are therefore fundamental to unravel the diagenetic and speleogenetic processes that may affect this kind of reservoirs. In this work we investigated an exhumed and silicified Neoproterozoic carbonate sequence in Brazil hosting a 1.4 km‐long cave. Quartz mineralization and silicified textures were analyzed with a multidisciplinary approach combining petrography, fluid inclusion microthermometry, silicon‐oxygen stable isotope analyses, and U‐Th‐Pb dating of monazite crystals. We found that an early silicification event caused the replacement of the dolostone layers with micro‐crystalline quartz forming chert nodules. This event was likely associated with mixing fluids (ancient Neoproterozoic seawater and hydrothermal solutions sourced from the underlying Mesoproterozoic basement) at relatively low temperatures (ca. 50‐100 °C) and shallow depth. After the tectonic deformation produced by the Brasiliano orogeny, silica dissolution was promoted by high temperature and alkaline hydrothermal solutions rising from the quartzite basement along deep‐rooted structures. Hypogene hydrothermal alteration promoted the dissolution of the cherty layers and the precipitation of chalcedony and megaquartz. Homogenization temperatures from primary fluid inclusions in megaquartz cement indicate minimum formation temperatures of 165‐210 °C. Similar temperature estimates (110‐200 °C) were obtained from the δ30Si and δ18O isotope systematics of quartz precipitated from hydrothermal solutions. The dissolved salts in the fluid inclusions were evaluated as NaCl+CaCl2 from microthermometric data combined with cryogenic Raman spectroscopy, corresponding to salinity ranging between 17 and 25 wt.%. No reliable age constraints for hydrothermal silica dissolution‐precipitation phases were obtained from monazite U‐Th‐Pb dating. However, our results, interpreted in the regional context of the São Francisco Craton, suggest that the Cambrian tectono‐thermal events could have been among the possible drivers for this hypogene process in the basin.
... 13,[15][16][17] With regard to MgCl 2 hydrates, there are also many related works on their structural and dynamic properties. For example, X-ray diffraction (XRD) 18,19 and Raman spectroscopy 20,21 were used to study the structural features and specific vibration modes of hydrates formed by cooling crystallization of MgCl 2 aqueous solution, respectively. Besides, infrared-visible sum frequency generation (SFG) spectroscopy was utilized to reveal the crystallization kinetics of MgCl 2 and other salt solutions on a sapphire surface by freezing and melting. ...
The interaction of MgCl2 with H2O is heavily involved in biological and chemical processes. In this work, freezing-induced hydrate formation from MgCl2 aqueous solution was monitored using terahertz time-domain spectroscopy. At low temperatures, two phase transitions from brine to hydrate formation could be clearly observed, and the formation of hydrate was accompanied by the emergence of new THz fingerprint peaks at 1.02, 1.56, and 1.84 THz, respectively. Integrating XRD and quantum chemical calculations, we attributed the absorption peaks to the vibrational modes of the formed MgCl2·12H2O. This demonstrates the potential of THz spectroscopy for application in the detection of biological processes in low-temperature environments, such as cell freezing.
... Laser Raman spectroscopic analyses of fluid inclusions demonstrate that H 2 O is dominant in the liquid phase in both sphalerite-and quartzhosted type 1 inclusions; this is indicated by the broad asymmetric H 2 O stretching band in the wave number range 2800 to 3800 cm − 1 . This spectrum can be deconvolved with three Gaussian-Lorentzian best-fit functions (Bakker, 2004), with peak positions at 3228 cm − 1 , 3441 cm − 1 and 3621 cm − 1 (Fig. 13 A). The position of the first peak can be used to estimate the salinity in terms of equivalent mass% NaCl (Baumgartner and Bakker, 2009) yielding approximately 3 mass%, which correlates well to the salinity obtained from microthermometry. ...
The polymetallic Chah-Mesi epithermal vein deposit is located about 2.5 km south of the Meiduk porphyry Cu-(Mo-Au) deposit in the Kerman Cenozoic Magmatic Arc (Kerman Belt), representing the southeastern sector of the Urumieh-Dokhtar Magmatic Belt in Iran. The veins are N-S to NNE-SSW oriented and hosted in volcanic rocks of basaltic, andesitic to dacitic composition and pyroclastics, which were affected by intense local silicification and sericitization in proximity to mineralized veins. Propylitic, argillic, as well as potassic alteration show a more regional distribution; the latter only observed closer to the Meiduk deposit. Mineralization occurs in various types of veins (massive, banded, crustiform) and to minor extent in replacement and breccia bodies. It encompasses several stages: An early higher-sulfidation stage, characterized by pyrite, chalcopyrite, enargite/luzonite and bornite, is followed by the main intermediate-sulfidation state assemblage with pyrite, chalcopyrite, tetrahedrite group minerals and sphalerite. The late Pb-Zn rich stage with sphalerite, galena, chalcopyrite and pyrite overprints the earlier associations. Gold and silver of up to 7 g/t and 150 g/t, respectively, are associated with the main and late stages of mineralization. The main carriers of these precious metals are Ag-rich gold (electrum) and tetrahedrite; other Ag-bearing sulfosalts like pearceite are rare. The chemical composition of tetrahedrite group minerals ranges from tennantite-(Fe) to tetrahedrite-(Fe) and tetrahedrite-(Zn) exhibiting a positive correlation between Sb and Ag contents. The tetrahedrite group minerals show complex zoning and display an increase of Sb away from the Meiduk deposit. Primary fluid inclusions in sphalerite and quartz from the banded and crustiform veins are low saline aqueous H2O-salt inclusions with only traces of CO2. Homogenization temperatures of two-phase LV inclusions (Th LV→L) have an average of 210 °C in sphalerite and 260 °C in quartz. Salinity values range from 1.2 to 9.9 and 2.1 to 9.2 mass% NaCl equivalent in sphalerite and quartz, respectively with an average of c. 6 mass% NaCl equiv. Low CO2 concentrations in the vapor phase detected by Raman spectroscopy together with previously published stable isotope data indicate fluids of magmatic origin as the main fluid source that were mixed with meteoric water. Mineralization is linked to ascending hydrothermal fluids which evolved from high- to intermediate-sulfidation state due to cooling, dilution with meteoric water and progressing fluid-wallrock interaction. Similar low salinity, but higher CO2-bearing fluids were previously reported from the nearby Meiduk porphyry deposit. Conclusively, Chah-Mesi is classified as an intermediate-sulfidation epithermal deposit that developed in the peripheral parts of the Meiduk porphyry system.
... To extract the physicochemical properties of unknown inclusions from the measured Raman spectra, experimental calibrations related to spectral features to the P-V-T-X properties of fluids or the strains and crystal orientations of minerals have been the subject of many studies (e.g., Frezzotti et al., 2012;Angel et al., 2019). Furthermore, the combined technique of microthermometry and Raman spectroscopy enables accurate estimation of the temperatures of phase transition in situ, even for phases that are difficult to assess under optical observation (e.g., Bakker, 2004). Typically, to obtain Raman spectra of an inclusion having a sufficient signalto-noise ratio for quantitative analysis, laser power of tens to hundreds of milliwatts is necessary, thereby necessitating focal intensities as high as several gigawatts per square centimeter. ...
Raman spectroscopy for fluid, melt, and mineral inclusions provides direct insight into the physicochemical conditions of the environment surrounding the host mineral at the time of trapping. However, the obtained Raman spectral characteristics such as peak position are modified because of local temperature enhancement of the inclusions by the excitation laser, which might engender systematic errors and incorrect conclusions if the effect is not corrected. Despite the potentially non-negligible effects of laser heating, the laser heating coefficient (B) (°C/mW) of inclusions has remained unsolved. For this study, we found B from experiments and heat transport simulation to evaluate how various parameters such as experimental conditions, mineral properties, and inclusion geometry affect B of inclusions. To assess the parameters influencing laser heating, we measured B of a total of 19 CO2-rich fluid inclusions hosted in olivine, orthopyroxene, clinopyroxene, spinel, and quartz. Our results revealed that the measured B of fluid inclusions in spinel is highest (approx. 6 °C/mW) and that of quartz is lowest (approx. 1 × 10−2 °C/mW), consistent with earlier inferences. Our simulation results show that the absorption coefficient of the host mineral is correlated linearly with B. It is the most influential parameter when the absorption coefficient of the host mineral (αh) is larger than that of an inclusion (αinc). Furthermore, although our results indicate that both the inclusion size and depth have little effect on B if αh > αinc, the thickness and radius of the host mineral slightly influence B. These results suggest that the choice of inclusion size and depth to be analyzed in a given sample do not cause any systematic error in the Raman data because of laser heating, but the host radius and thickness, which can be adjusted to some degree at the time of sample preparation, can cause systematic errors between samples.
Our results demonstrate that, even with laser power of 10 mW, which is typical for inclusion analysis, the inclusion temperature rises to tens or hundreds of degrees during the analysis, depending especially on the host mineral geometry and optical properties. Therefore, correction of the heating effects will be necessary to obtain reliable data from Raman spectroscopic analysis of inclusions. This paper presents some correction methods for non-negligible effects of laser heating.
... As a non-destructive and single-inclusion analytical method, the most successful use of Raman spectroscopy in fluid inclusion studies has been mainly in the analysis of volatiles, with relatively limited application in solute analysis due to the non-sensitivity of monoatomic cations such as Na + , K + , Ca 2+ , and Mg 2+ to Raman [3]. However, it has been shown that salt hydrates with various numbers of H 2 O molecules in the crystal structure at low temperatures are sensitive to Raman [4], and thus cryogenic Raman spectroscopy has been increasingly used to study the solute composition of fluid inclusions [5][6][7][8]. A number of cryogenic Raman studies have been conducted for the H 2 O-NaCl-CaCl 2 system, which represents a common type of geologic fluid [1,9,10]. ...
Various analytical techniques have been developed to determine the solution composition of fluid inclusions, including destructive, non-destructive, single-inclusion, and bulk-inclusion methods. Cryogenic Raman spectroscopy, as a non-destructive and single-inclusion method, has emerged as a potentially powerful tool of quantitative analysis of fluid inclusion composition. A method of point analysis using cryogenic Raman spectroscopy has been previously proposed to quantitatively estimate the solute composition of H2O-NaCl-CaCl2 solutions, but there are uncertainties related to heterogeneity of frozen fluid inclusions and potential bias in the processing of Raman spectra. A new method of quantitative analysis of solute composition of H2O-NaCl-CaCl2 solutions using Raman mapping technology is proposed in this study, which can overcome the problems encountered in the point analysis. It is shown that the NaCl/(NaCl + CaCl2) molar ratio of the solution, X(NaCl, m), can be related to the area fraction of hydrohalite over hydrohalite plus antarcticite, Fhydrohalite, by the equation X(NaCl, m) = 1.1435 Fhydrohalite − 0.0884, where Fhydrohalite = hydrohalite area/(hydrohalite area + antarcticite area). This equation suggests that the molar fraction of a salt component may be estimated from the fraction of the Raman peak area of the relevant hydrate. This study has established a new way of estimating solute composition of fluid inclusions using cryogenic Raman mapping technique, which may be extended to other solutions.
... Microthermometry results. Microthermometric measurement was designed to obtain the homogenization temperature of saline water inclusions, because the homogenization temperature of saline water inclusions was considered more reliable to represent the trapping temperature than that of the hydrocarbon or gas inclusions (Hanor, 1980;Pan et al., 2006;Roedder, 1984), so that the generations of inclusions can be divided and the matching relation of each generation of homogenization temperature and real geo-temperature can be achieved, and paragenesis of the FIs often determined by contrasting homogenization temperature values of saline water inclusions (Bakker, 2004;Burke, 2001;Tao et al., 2010). ...
The Juhugeng mining area in the Qilian Mountains is the only district of China where terrestrial gas hydrate has been found. This paper aimed at studying the gas migration for gas hydrates based on fluid inclusion and apatite fission track experiments with samples being collected in both the hanging wall (Triassic strata, non-hydrocarbon source rocks) and footwall (Jurassic strata, hydrocarbon source rocks) of drilling cores. Fluid inclusions are found in both the hanging wall and footwall, and are characterized by two generations: the first generation includes gaseous and liquid hydrocarbon fluid inclusions with the homogenization temperature of concomitant saline water inclusions being 83–115°C, and the second generation includes gaseous fluid inclusions with the concomitant homogenization temperature of saline water inclusions being 115–149 °C, suggesting two periods of gas migration. Combining with the reconstruction of the burial and thermal histories, the gas migration history can be elaborated as follows: (1) In the Late Paleogene period (>30 Ma), the gas in the footwall migrated to the hanging wall because of the thrusting of Triassic strata, with the temperature being more than 110 ± 10°C (derived from apatite fission track results), corresponding well with the homogenization temperature of the saline water inclusions of the first generation being 115–149 °C; (2) In the Late Neogene to Quaternary (<8 Ma), the study area were impacted by the intensive faults, leading to the second gas migration with a good match between temperature lower than 110 ± 10°C (derived from apatite fission track results) and the homogenization temperature of saline water inclusions in the second generation (83–115 °C), and the geological age of the second gas migration can be restricted from 8 to 1.8 Ma. The permafrost was formed in Quaternary, so the controversial gas hydrate formation pattern can be determined that the gas should be accumulated before the permafrost was formed.
... Recording time was 150 sec in the case of each spectrum with 30 sec accumulation periods. Raman spectra of salt hydrates can be found in the range of 3000-3700 cm −1 with a most important peaks around 3400 cm −1 [41,42]. During Raman spectroscopy-assisted microthermometry, the Linkam THMSG 600 heating-freezing stage was mounted on the Raman spectrometer. ...
In the basement areas of the southern Pannonian Basin, Central Europe (Tisia Composite Terrane, Hungary), Variscan blocks are essential components. The existing paleogeographic reconstructions, however, are often unclear and contradictory. This paper attempts to give a contribution for paleogeographic correlation of the Tisia using paleohydrological features (e.g., vein mineralization types, inclusion fluid composition and origin) of the Pennsylvanian continental succession and neighboring crystalline complexes. Vein-type mineralization in the studied samples dominantly forms blocky morphological types with inclusion-rich quartz and carbonate crystals. The evolution of hydrothermal mineralization and host rock alteration in the study area comprises three major stages. The first one is characterized by chloritization, epidotization, and sericitization of metamorphic rocks together with subsequent formation of Ca-Al-silicate and quartz-sulfide veins (clinopyroxene-dominant and epidote-dominant mineralization). The related fluid inclusion record consists of high-temperature and low-salinity aqueous inclusions, corresponding to a reduced retrograde-metamorphic fluid phase during the Late Westphalian (~310 Ma). The next mineralization stage can be related to a generally oxidized alkaline fluid phase with a cross-formational character (hematite-rich alkali feldspar-dominant and quartz-dolomite veins). High-salinity primary aqueous inclusions probably were originated from the Upper Permian playa fluids of the region. The parent fluid of the third event (ankerite-hosted inclusions) was derived from a more reductive and low-salinity environment and can represent a post-Variscan fluid system. Fluid evolution data presented in this paper support that the W Tisia (Mecsek–Villány area) belonged to the Central European Variscan belt close to the Bohemian Massif up to the Early Alpine orogenic phases. Its original position is presumably to the northeast from the Bohemian Massif at the Late Paleozoic, north to the Moravo-Silesian Zone. The presented paleofluid evolution refines previous models of the paleogeographic position of the Tisia and puts constraints on the evolution of the Variscan Europe.
1. Introduction
In the basement areas of the Pannonian Basin, Central Europe (Hungary), pre-Variscan and Variscan blocks are essential components [1–4]. Late Variscan age granitoids are known in the Tisia Composite Terrane or Tisza Mega-unit (e.g., ca. 330–360 Ma, Mórágy Granite Complex) where locally marine Silurian and terrestrial Permo-Carboniferous (meta) sediments are also preserved (Figure 1). Based on its Variscan and early Alpine tectonostratigraphic characteristics, the Tisia was located at the margin of the European Plate prior to a rifting period in the Middle Jurassic [5–7]. The existing paleogeographic reconstructions, based on the correlation of the Paleozoic and Mesozoic facies belts in the Alpine–Carpathian domain, however, are contradictory (Figure 2). On the one hand, at the end of the Variscan cycle, the polymetamorphic complexes of the Tisia belonged to the southern part of the Moldanubian Zone, forming the European margin of the Paleo-Tethys [2, 3, 5]. Position of the Tisia can be determined east to the Bohemian Massif and to the Western Carpathians (Figure 2(a)).
... It was not possible to determine the dissolved salt species in the fluid inclusions, because the dissolved salt species in the solutions did not have characteristic peaks in the Raman spectrum. They only affected the distribution range or intensity of the Raman signals (Burke, 2001;Bakker, 2004;Baumgartner and Bakker, 2009;Frezzotti et al., 2012). Despite that, Type IIIa inclusions in garnet (Fig. 12a), epidote (Fig. 12b), and quartz (Fig. 12c, d) were found to rarely contain CH 4 according to the characteristic CH 4 peak of spectra at around 2917 cm −1 . ...
... Despite that, Type IIIa inclusions in garnet (Fig. 12a), epidote (Fig. 12b), and quartz (Fig. 12c, d) were found to rarely contain CH 4 according to the characteristic CH 4 peak of spectra at around 2917 cm −1 . It has been confirmed from other studies that the given peak values correspond to CH 4 species in the fluid inclusions (Burke, 2001;Bakker, 2004;Lin et al., 2007;Lin and Bodnar, 2010). These CH 4 species were only detected in three of 18 measured samples. ...
... The green asterisk (*) represents the MgCl 2 ·2H 2 O peaks that suggest that the MgCl 2 ·1H 2 O is rehydrated to MgCl 2 ·2H 2 O that was published by many authors in fluid inclusion study community since 1980s. [23][24][25] In those studies, the MgCl 2 ·12H 2 O was formed by microthermometry from salty brine of the fluid inclusion and then took the in situ Raman spectrum of this phase. Because these published Raman spectra of MgCl 2 ·12H 2 O in different temperature ranges and at different spectral resolutions are all consistent with each other, we would consider that the matching of our Raman spectrum with theirs is a good confirmation of the identity of MgCl 2 ·12H 2 O (for a detailed description, see in Section 3.3). ...
