Distribution of Microcrystalline Quartz in Glassy Fulgurites from Garuamukh and Kimin, India

Saikia, Basanta; Parthasarathy, G.; Borah, Rashmi R.

doi:10.4236/jamp.2015.310161

Cited by 5 publications

(2 citation statements)

References 27 publications

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“…The Si-O symmetrical bending vibrational peak at 695 cm -1 of the octahedral site symmetry is unique to the crystalline materials. All infrared spectra reveals peak at this range, therefore crystalline quartz particles present in the observed samples [28]- [30]. The infrared spectra reveals bands at 1014 -1018 cm −1 are close to the SiO deformation band obtained for kaolinite.…”

Section: Resultssupporting

confidence: 74%

Raman and FTIR Spectroscopic Evaluation of Clay Minerals and Estimation of Metal Contaminations in Natural Deposition of Surface Sediments from Brahmaputra River

Saikia¹,

Parthasarathy²,

Borah³

et al. 2016

IJG

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This study demonstrates the compositional and structural analysis of surface sediments in natural depositional environment of the Brahmaputra River using X-ray fluorescence, Raman spectroscopic and Fourier transform infrared spectroscopic techniques. The main peaks in the Raman and infrared spectra reflected Al-OH, Al-O and Si-O functional groups in high frequency stretching and low frequency bending modes. The Raman and infrared spectra reveals the nature of clay (kaolinite) associated with quartz. The infrared spectra are indicative to the weathered metamorphic origin of the silicate minerals. The relative distributions of the contaminations in the sediment are: Si > Al > Fe > Mg > Ca > K > Ti > Mn > Cr >Ni > Zn > Cu > Co. The metal contaminations in the sediments are investigated by calculating the enrichment factor, contamination factor, geo-accumulation index and pollution load index. The relative distributions of the contamination among the samples are: Cu > Si > Mn > Mg > Ni > Cr > Ti > Al > Co > Pb > K > Ca > Zn. The investigating factors suggest the significant contamination in the sediment is due to Cu. The strong positive correlation among Al, Fe, Mg and K suggests association of sediments with clay. The elemental correlation is indicative to the metamorphosed pyrophanite (MnTiO3) deposition.

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Section: Resultssupporting

confidence: 74%

Raman and FTIR Spectroscopic Evaluation of Clay Minerals and Estimation of Metal Contaminations in Natural Deposition of Surface Sediments from Brahmaputra River

Saikia¹,

Parthasarathy²,

Borah³

et al. 2016

IJG

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“…As it is difficult to directly observe the properties of lightning passing through the soil, including the energy deposited (between 1 and 30 MJ m –1 ), lightning channel width (~1 mm diameter), and peak temperatures (in the order of 1000 K s –1 ), fulgurites are potentially a source of data to investigate the heating and cooling rates associated with lightning effects on the ground, providing important clues about the properties of lightning moving underground [ 4 ]. The differential mineral compositions within the fulgurites, in particular those observed from the inner part of the fulgurites (core compartment) and the more external domain (shell), are also a relevant piece of information and, because of that, the mineral composition of fulgurites and their change in going from core to shell regions have been the subject of several studies, aiming at establishing different types of correlations between these composition or/and compositional changes, as well as the fulgurites’ formation mechanism [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ].…”

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confidence: 99%

Micro-Raman Spectroscopy and X-ray Diffraction Analyses of the Core and Shell Compartments of an Iron-Rich Fulgurite

et al. 2022

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Fulgurites are naturally occurring structures that are formed when lightning discharges reach the ground. In this investigation, the mineralogical compositions of core and shell compartments of a rare, iron-rich fulgurite from the Mongolian Gobi Desert were investigated by X-ray diffraction and micro-Raman spectroscopy. The interpretation of the Raman data was helped by chemometric analysis, using both multivariate curve resolution (MCR) and principal component analysis (PCA), which allowed for the fast identification of the minerals present in each region of the fulgurite. In the core of the fulgurite, quartz, microcline, albite, hematite, and barite were first identified based on the Raman spectroscopy and chemometrics analyses. In contrast, in the shell compartment of the fulgurite, the detected minerals were quartz, a mixture of the K-feldspars orthoclase and microcline, albite, hematite, and goethite. The Raman spectroscopy results were confirmed by X-ray diffraction analysis of powdered samples of the two fulgurite regions, and are consistent with infrared spectroscopy data, being also in agreement with the petrographic analysis of the fulgurite, including scanning electron microscopy with backscattering electrons (SEM-BSE) and scanning electron microscopy with energy dispersive X-ray (SEM-EDX) data. The observed differences in the mineralogical composition of the core and shell regions of the studied fulgurite can be explained by taking into account the effects of both the diffusion of the melted material to the periphery of the fulgurite following the lightning and the faster cooling at the external shell region, together with the differential properties of the various minerals. The heavier materials diffused slower, leading to the concentration in the core of the fulgurite of the iron and barium containing minerals, hematite, and barite. They first underwent subsequent partial transformation into goethite due to meteoric water within the shell of the fulgurite. The faster cooling of the shell region kinetically trapped orthoclase, while the slower cooling in the core area allowed for the extensive formation of microcline, a lower temperature polymorph of orthoclase, thus justifying the prevalence of microcline in the core and a mixture of the two polymorphs in the shell. The total amount of the K-feldspars decreases only slightly in the shell, while quartz and albite appeared in somewhat larger amounts in this compartment of the fulgurite. On the other hand, at the surface of the fulgurite, barite could not be stabilized due to sulfate lost (in the form of SO2 plus O2 gaseous products). The conjugation of the performed Raman spectroscopy experiments with the chemometrics analysis (PCA and, in particular, MCR analyses) was shown to allow for the fast identification of the minerals present in the two compartments (shell and core) of the sample. This way, the XRD experiments could be done while knowing in advance the minerals that were present in the samples, strongly facilitating the data analysis, which for compositionally complex samples, such as that studied in the present investigation, would have been very much challenging, if possible.

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Characterization of weathering profile and quality of groundwater over hard rock terrain

et al. 2021

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Distribution of Microcrystalline Quartz in Glassy Fulgurites from Garuamukh and Kimin, India

Cited by 5 publications

References 27 publications

Raman and FTIR Spectroscopic Evaluation of Clay Minerals and Estimation of Metal Contaminations in Natural Deposition of Surface Sediments from Brahmaputra River

Raman and FTIR Spectroscopic Evaluation of Clay Minerals and Estimation of Metal Contaminations in Natural Deposition of Surface Sediments from Brahmaputra River

Micro-Raman Spectroscopy and X-ray Diffraction Analyses of the Core and Shell Compartments of an Iron-Rich Fulgurite

Characterization of weathering profile and quality of groundwater over hard rock terrain

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