Reflectance spectroscopy and ASTER based mapping of rock-phosphate in parts of Paleoproterozoic sequences of Aravalli group of rocks, Rajasthan, India

Guha, Arindam; Kumar, K. Vinod; Porwal, Alok; Rani, Komal; Sahoo, K. C.; Kumar, S.R. Aneesh; Singaraju, Vuddaraju; Singh, Ravindra; Khandelwal, Manoj; Raju, P. V. Sunder; Diwakar, P. G.

doi:10.1016/j.oregeorev.2018.02.021

Cited by 23 publications

(8 citation statements)

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“…Similar grade estimation may not be possible in VNIR-SWIR spectral domain as grade sensitive spectral feature is absent in the VNIR-SWIR domain. However, small patchy exposures of phosphorite which can be detected using spectral contrast of dolomite and phosphorite in ASTER SWIR band product based on the implementation of subpixel mapping approach can be subdued in the TIR band based product proposed for phosphorite [30]. This is due to intratarget spectral mixing of dolomite and small patchy exposure of phosphorite, which would hinder the detection of small exposures in broadband, coarse resolution thermal bands of ASTER.…”

Section: Resultsmentioning

confidence: 99%

“…A wavelength dispersive XRF instrument (MagiX Pro PW 244-PANalytical model) was used to estimate the major oxides with the primary emphasis on understanding the variation of P 2 O 5 content in the phosphorite samples. Sample preparation method followed for collecting XRD and XRF data is similar to the method; which has been discussed in the literature [30].…”

Section: Mineralogical and Chemical Datamentioning

confidence: 99%

“…There has been an attempt to delineate phosphorite from dolomite using the contrast of their reflectance spectra [30]. This spectral contrast in the visible near infrared (VNIR) and SWIR domain is due to the presence of a secondary vibrational feature (overtone and combination) of carbonate mineral in dolomite and absence of such feature in the phosphorite [31,32].…”

Section: Introductionmentioning

confidence: 99%

“…Results of XRD and X-ray fluorescence (XRF) analysis of representative samples of phosphorite and dolomite to identify the presence of the dominant mineral phases and their relative proportion along with the P 2 O 5 Content[30].…”

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confidence: 99%

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Emittance Spectroscopy and Broadband Thermal Remote Sensing Applied to Phosphorite and Its Utility in Geoexploration: A Study in the Parts of Rajasthan, India

et al. 2019

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The contrast in the emissivity spectra of phosphorite and associated carbonate rock can be used as a guide to delineate phosphorite within dolomite. The thermal emissivity spectrum of phosphorite is characterized by a strong doublet emissivity feature with their absorption minima at 9 µm and 9.5 µm; whereas, host rock dolomite has relatively subdued emissivity minima at ~9 µm. Using the contrast in the emissivity spectra of phosphorite and dolomite, data obtained by the thermal bands of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor were processed to delineate phosphorite within dolomite. A decorrelation stretched ASTER radiance composite could not enhance phosphorite rich zones within the dolomite host rock. However, a decorrelation stretched image composite of selected emissivity bands derived using the emissivity normalization method was suitable to enhance large surface exposures of phosphorite. We have found that the depth of the emissivity minima of phosphorite gradually has increased from dolomite to high-grade phosphorite, while low-grade phosphate has an intermediate emissivity value and the emissivity feature can be studied using three thermal bands of ASTER. In this context, we also propose a relative band depth (RBD) image using selected emissivity bands (bands 11, 12, and 13) to delineate phosphorite from the host rock. We also propose that the RBD image can be used as a proxy to estimate the relative grades of phosphorites, provided the surface exposures of phosphorite are large enough to subdue the role of intrapixel spectral mixing, which can also influence the depth of the diagnostic feature along with the grade. We have validated the phosphorite pixels of the RBD image in the field by carrying out colorimetric analysis to confirm the presence of phosphorite. The result of the study indicates the utility of the proposed relative band depth image derived using ASTER TIR bands for delineating Proterozoic carbonate-hosted phosphorite.

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Section: Resultsmentioning

confidence: 99%

Section: Mineralogical and Chemical Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Emittance Spectroscopy and Broadband Thermal Remote Sensing Applied to Phosphorite and Its Utility in Geoexploration: A Study in the Parts of Rajasthan, India

et al. 2019

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“…The reflectance spectra of rocks/substances can be collected from any distance; therefore, it is also suitable for imaging surface mineralogical variations from remote platforms 7 . Reflectance spectroscopy has been widely used to spatially map rocks and minerals on different planets and also on the Earth's surface as different minerals have different electronic and vibrational absorption features [9][10][11][12][13][14][15][16][17] . More often, these spectral contrasts are being upscaled to the imaging reflectance spectroscopic data collected by space-based sensors for remote mapping of rocks and minerals 6,7,18 .…”

Section: Potential Utility Of Reflectance Spectroscopy In Understandimentioning

confidence: 99%

Potential utility of reflectance spectroscopy in understanding the paleoecology and depositional history of different fossils

Chaudhuri

Guha

Bhaumik

et al. 2020

Sci Rep

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The potential of reflectance spectroscopy to infer the paleoecological and depositional evolution of different micro and macro invertebrate fossils has been evaluated by analyzing their reflectance spectra within the spectral domain of 350–2500 nm using the FIELDSPEC3 spectroradiometer. Mineralogical information derived from the rapid and non-destructive spectral analysis has been substantiated using concurrent mineralogical data from conventional geochemical analyses. The diagnostic Fe-crystal field effect induced spectral features are identified on the representative spectra of different benthic foraminifera. These spectral features are resulted due to the incorporation of Fe during the biomineralization process. These features are absent in planktic foraminifera. The encrustation of Fe-oxides is inferred to be responsible for imprinting the Fe-crystal field feature in the spectra of micro and macrofossils at 900–1200 nm. Vibrational spectral features of the Al–OH bond are also identified. Both of these features are an indicator of post-depositional diagenetic history. The presence of Al and Fe in macrofossil shells is also believed to be related to ecological conditions as these elements are biogenically incorporated during shell formation. This study reveals the value of reflectance spectroscopy to infer ecological behavior and post-depositional environment of different organisms.

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Targeting the bauxite rich pockets from lateritic terrain utilizing ASTER data: A case study from Kabirdham District, Chhattisgarh, India

Sarkar

Sur

2021

J Earth Syst Sci

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Reflectance spectroscopy and ASTER based mapping of rock-phosphate in parts of Paleoproterozoic sequences of Aravalli group of rocks, Rajasthan, India

Cited by 23 publications

References 53 publications

Emittance Spectroscopy and Broadband Thermal Remote Sensing Applied to Phosphorite and Its Utility in Geoexploration: A Study in the Parts of Rajasthan, India

Emittance Spectroscopy and Broadband Thermal Remote Sensing Applied to Phosphorite and Its Utility in Geoexploration: A Study in the Parts of Rajasthan, India

Potential utility of reflectance spectroscopy in understanding the paleoecology and depositional history of different fossils

Targeting the bauxite rich pockets from lateritic terrain utilizing ASTER data: A case study from Kabirdham District, Chhattisgarh, India

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