The near-infrared (NIR) spectra of powdered calcite in the 3–121 μm mode particle size range

Hopkinson, Laurence; Kristová, Petra; Rutt, K. J.

doi:10.1016/j.vibspec.2017.03.006

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…This evolution has already been seen by Roush (), who showed that a decrease in grain size (from 500 to <45 μm) causes a decrease of the absorptions near 2.30 and 2.50 μm, and by Salisbury et al () and Salisbury and Walter (), who showed the amplification of the absorptions near 3.40 and 3.80 μm. The decrease of the absorptions near 2.30 and 2.50 μm with the grain size was also described in Hopkinson et al () for a grain size range from <3 to 121 μm.…”

Section: Methodssupporting

confidence: 73%

Detection of Carbonates in Martian Weathering Profiles

et al. 2019

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Noachian surfaces on Mars exhibit vertical assemblages of weathering horizons termed as weathering profiles; this indicates that surface water caused alteration of the rocks that required a different, warmer climate than today. Evidence of this early Martian climate with CO2 vapor as the main component causing greenhouse warming has been challenged by the lack of carbonate in these profiles. Here we report the analysis of Compact Reconnaissance Imaging Spectrometer for Mars L‐detector data leading to the detections of carbonates using a spectral signature exclusively attributed to them. The carbonates are collocated with hydroxylated minerals in weathering profiles over the Martian surface. The origin of CO2 for the formation of carbonates could be the atmosphere. The widespread distribution of weathering profiles with carbonates over the surface of the planet suggest global interactions between fluids containing carbonate/bicarbonate ions with the surface of Mars in the presence of atmospheric water until around 3.7 billion years ago.

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Section: Methodssupporting

confidence: 73%

Detection of Carbonates in Martian Weathering Profiles

et al. 2019

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“…A faint and narrow spectral feature present near 1.75 µm (5714 cm −1 ) could result from CO −2 3 absorption (Gaffey, 1986). In addition, two other small and narrow features are also present in the spectra of calcite around 2.0 µm (5000 cm −1 ) that are interpreted as overtones of the degenerate v 3 combined with the non-degenerate v 1 or its overtone [59]. These three features were not analyzed in this work because they were too narrow and not detectable in the mixtures' spectra.…”

Section: Reflectance Spectroscopy Of Sample Endmembers and Mixturesmentioning

confidence: 94%

Study of Detection Limits of Carbonate Phases in Mixtures with Basaltic-like Fine Regolith in the MIR (1–5.5 µm) Spectral Range

et al. 2023

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The presence of minerals formed under the occurrence of liquid water during the first billion years on Mars was a key discovery, but there is still a large number of open issues that make the study of these mineral deposits a main focus of remote sensing and laboratory studies. Moreover, even though there is extensive research related to the study of the spectral behavior of mixtures, we still lack a full understanding of the problem. The main goal of this work is the analysis of the detection limits of hydrated and carbonate phases within mixtures with basaltic-like fine regolith in the spectral region 1.0–5.5 µm (1818–10,000 cm−1). We selected two different basalt samples and mixed them with two carbonate phases: a dolomite and a calcite. Spectral features have been investigated isolating the main carbonate absorption features and overtones; deriving trends of spectral parameters such as band depth, band area, full-width-half-maximum; percentage and grain size variations. The results obtained in this work show how the presence of a basaltic component can strongly influence the appearance of the hydrated and carbonate features showing different trends and intensities depending on the grain size and percentage of the carbonate components.

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Physicochemical mechanisms of FT-NIRS age prediction in fish otoliths

et al. 2022

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Context Fourier transform near-infrared spectroscopy (FT-NIRS) is of interest to fisheries managers for rapid age prediction in fish otoliths, yet the underlying prediction mechanism is unknown. Aims To better understand drivers of FT-NIRS age prediction, we evaluated FT-NIRS spectra and age prediction models for otoliths of red snapper, Lutjanus campechanus, related to otolith structure, mass, and constituents (calcium carbonate (CaCO3) and protein). Methods Spectra were collected from a set of whole otoliths (n = 84, 0–28 years) and again sequentially after grinding to powder and subsampling a fixed mass of each ground otolith. Protein content was also measured (n = 26) and related to spectra. Key results Age prediction was diminished in ground and fixed-mass otolith models, but remained within 2 years of traditional ages. Protein content (0.43–0.92% weight) increased significantly with age, implying a concomitant decrease in CaCO3 content. FT-NIRS models predicted protein content to within 0.04%, but protein variability hindered modelling. Spectral characteristics of both CaCO3 and protein are evident in otolith spectra and are implicated in age-prediction models. Conclusions Changes in otolith composition, mass, and structure underlie FT-NIRS age prediction, but compositional changes inform the majority of age prediction. Implications These results provide a foundation for understanding FT-NIRS age prediction.

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The near-infrared (NIR) spectra of powdered calcite in the 3–121 μm mode particle size range

Cited by 3 publications

References 12 publications

Detection of Carbonates in Martian Weathering Profiles

Detection of Carbonates in Martian Weathering Profiles

Study of Detection Limits of Carbonate Phases in Mixtures with Basaltic-like Fine Regolith in the MIR (1–5.5 µm) Spectral Range

Physicochemical mechanisms of FT-NIRS age prediction in fish otoliths

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