μ-FTIR mapping: Distribution of impurities in different types of diamond growth

Howell, D.; O’Neill, Craig; Grant, Kevin; Griffin, William L.; Pearson, Norman J.; O’Reilly, Suzanne Y.

doi:10.1016/j.diamond.2012.06.003

Cited by 63 publications

(37 citation statements)

References 38 publications

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“…The uncertainty on each d 13 C analysis (95 % confidence) is B0.15 %. Uncertainties on the IR data are \10 % for nitrogen concentration, \20 cm -2 for I(B 0 ), and \3 cm -1 for the height of the primary hydrogen band (Howell et al 2012b) Contrib Mineral Petrol major stratigraphic boundary, but that does not appear to be the case on the other side. Due to the way the sample has been cut, we cannot tell if further cuboid growth developed beyond Layer B.…”

Section: Layer Bmentioning

confidence: 89%

“…All of this is done automatically, and it can loop through as many spectra as the map contains. Tests have shown that this method returns data comparable to those of the CAXBD97.xls method (by Dr. David Fisher, DTC Research) that is commonly applied to single spectra in geological studies, with a likely uncertainty of *10 % in nitrogen concentrations (Howell et al 2012b).…”

Section: Techniquesmentioning

confidence: 91%

“…The IR spectra were deconvoluted using the DiaMap open-source freeware developed within GEMOC (Howell et al 2012b). This type of spectral deconvolution involves taking the characteristic spectra of the various nitrogen defects (Fig.…”

Section: Techniquesmentioning

confidence: 99%

“…In this study, we apply FTIR mapping and a newly developed data-processing technique (DiaMap; Howell et al 2012b) to a diamond sample that exhibits several Fig. 1 Diagram showing the morphological changes of diamond crystals on a plot of growth rate versus driving force (after Sunagawa 2005) Contrib Mineral Petrol transitions between octahedral and cuboid growth and contains a few regions of mixed-habit growth.…”

Section: Introductionmentioning

confidence: 99%

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Platelet development in cuboid diamonds: insights from micro-FTIR mapping

Howell

O’Neill

Grant

et al. 2012

Contrib Mineral Petrol

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Fourier transform infrared mapping of diamonds can reveal detailed information on impurities, with a spatial context. We apply this technique, combined with in situ isotopic analysis of carbon, to the study of cuboid diamond growth in a sample that exhibits some mixedhabit growth. While there has been some uncertainty in the literature regarding sectoral differences in nitrogen aggregation and subsequent platelet development, the data from this study appear far more conclusive. We show that despite nitrogen being concentrated in octahedral sectors, there is no detectable difference in the concentrationadjusted rate of nitrogen aggregation within octahedral and cuboid sectors. However, the resultant platelet development is significantly reduced in cuboid sectors compared to contemporaneously formed octahedral sectors. This finding has significant implications for the classification of diamonds using the relationship between their platelet intensity and the absorption caused by B centres. It means that cuboid diamonds naturally fall below the linear relationship that has been termed regular, which would lead to them being incorrectly interpreted as having experienced heating or deformation. The data also support earlier suggestions that large hydrogen concentrations in the diamond-forming fluid may be required for cuboid growth. We further suggest that high nitrogen and hydrogen concentrations are required for mixed-habit diamond growth, which might be the product of specific fluid chemistries that occur in reducing mantle environments.

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Section: Layer Bmentioning

confidence: 89%

Section: Techniquesmentioning

confidence: 91%

Section: Techniquesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Platelet development in cuboid diamonds: insights from micro-FTIR mapping

Howell

O’Neill

Grant

et al. 2012

Contrib Mineral Petrol

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“…For maps, which might contain several thousand individual spectra, automated processing using software such as Diamap (Howell et al, 2012) is required. For consistency all the spectra presented here (linescans and maps) were processed using a Python program being developed in this laboratory by Laura Speich and Simon…”

Section: Sample Preparationmentioning

confidence: 99%

FTIR thermochronometry of natural diamonds: A closer look

Kohn

Speich

Smith

et al. 2016

Lithos

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms FTIR thermochronometry of natural diamonds: a closer lookSimon C. Kohn, Laura Speich, Christopher B. Smith and Galina P. Bulanova School of Earth Sciences, University of Bristol, Queens Rd., Bristol, BS8 1RJ, U.K. AbstractFTIR is a commonly-used technique for investigating diamonds, but much of the most useful information is lost if spatially resolved measurements are not used. In this study we show examples of FTIR core-to-rim line scans, maps with high spatial resolution and maps with high spectral resolution that are fitted to extract the spatial variation of different nitrogen and hydrogen defects. Model residence temperatures are calculated from the concentration of A and B centres using known times of annealing in the mantle, and a new, two-stage aggregation model is presented that better constrains the thermal history of the diamond and that of the mantle lithosphere in which the diamond resided. The effect of heterogeneity within the analyzed FTIR volume is quantitatively assessed and errors in model temperatures that can be introduced by studying whole diamonds instead of thin plates are discussed. The spatial distribution of hydrogen associated with the 3107 cm -1 vibration does not follow the same pattern as nitrogen, and an enrichment of hydrogen at the boundary between pre-existing diamond and diamond overgrowths is observed. There are several possible explanations for this observation including a change in chemical composition of diamond forming fluid during growth or kinetically controlled uptake of hydrogen.

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Internal diamond morphology: Raman imaging of metamorphic diamonds

Korsakov

Toporski²,

Dieing³

et al. 2015

J Raman Spectroscopy

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Confocal 2‐D and 3‐D Raman imaging of the Kokchetav metamorphic diamonds from different rock types reveals that these diamonds have a rather complex internal morphology. The diamond shows a strong change in the position of the diamond Raman line as well as the width of this line, which could be found both in the XY and in the YZ scan. These features indicate variations in the crystalline quality of the diamond. The broadest lines are located in the center of the octahedral diamond inclusion whereas the material close to the diamond–garnet interface shows smaller line widths. These features were also found for thermochemically extracted diamond crystals, which are not armored by host mineral, and in situ for inter‐ and intragranular diamond. Furthermore, host–garnet display no evidence for broadening or up‐shift of main Raman bands, indicating very low (below detection limit) residual strain. Thus the broadening and upshift of main diamond band do not relate to residual strain in inclusion–host systems. A comparison of Raman imaging results with cathodoluminescence images reveals that the distribution of defects, which cause the cathodoluminescence of diamond crystals, can be traced by Raman imaging. The 2‐D and 3‐D Raman imaging is a very powerful tool for study of internal morphology and growth pattern of metamorphic diamond, even it is a small crystal less than 10 µm in size. The growth pattern for octahedral diamond crystals from garnet–clinozoisite gneisses were obtained for the first time by Raman imaging. Copyright © 2015 John Wiley & Sons, Ltd.

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μ-FTIR mapping: Distribution of impurities in different types of diamond growth

Cited by 63 publications

References 38 publications

Platelet development in cuboid diamonds: insights from micro-FTIR mapping

Platelet development in cuboid diamonds: insights from micro-FTIR mapping

FTIR thermochronometry of natural diamonds: A closer look

Internal diamond morphology: Raman imaging of metamorphic diamonds

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