Macroscopic electrostatic effects in ATR-FTIR spectra of modern and archeological bones

Aufort, Julie; Lebon, Matthieu; Gallet, Xavier; Ségalen, Loïc; Gervais, Christel; Brouder, Christian; Balan, Etienne

doi:10.2138/am-2018-6320ccbyncnd

Cited by 13 publications

(11 citation statements)

References 25 publications

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“…; Aufort et al . , ). Its position has been shown to be well correlated to apatite crystallinity in archaeological heated bones (Lebon et al .…”

Section: Resultsmentioning

confidence: 99%

“…In contrast the position and line shape of weaker bands, such as the band at about 960 cm -1 related to the ν 1 PO 4 stretching mode, are less affected by these effects. Compared with the ν 4 PO 4 band, the weaker ν 1 PO 4 band is thus expected to provide a complementary meaningful insight into the atomic-scale properties of the sample (Balan et al 2011;Aufort et al 2016Aufort et al , 2018. Its position has been shown to be well correlated to apatite crystallinity in archaeological heated bones (Lebon et al 2014).…”

Section: Atomic-scale Order and Sample Micro-structure Probed By Atr-mentioning

confidence: 99%

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Assessing bone transformation in late Miocene and Plio‐Pleistocene deposits of Kenya and South Africa

Aufort

Gommery²,

Gervais

et al. 2019

Archaeometry

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Bone reactivity offers a potential way to record local physical–chemical conditions prevailing in fossilization environments and archaeological sites. In the present study, a series of fossil bone samples from the karstic environments of the Bolt's Farm cave system (Cradle of Humankind, South Africa) and from fluvio‐lacustrine environments of the Tugen Hills (Gregory Rift, Kenya) is analysed. The chemical composition and infrared and nuclear magnetic resonance (NMR) spectroscopic properties of fossil samples point to a transformation of the biogenic apatite and formation of secondary apatite. Depending on the sample, the secondary apatite corresponds to a carbonate‐bearing hydroxy‐ or fluor‐apatite. The maximum fraction of secondary apatite is close to 60%, coinciding with previous observations in experimental alteration of bone in aqueous solutions and suggesting that a fraction of pristine biological apatite is likely to be preserved. The present results also suggest that the acetic acid treatment of fossil samples moderately increases their average crystallinity but may dissolve carbonate‐rich domains of secondary apatite.

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“…; Aufort et al . , ). Its position has been shown to be well correlated to apatite crystallinity in archaeological heated bones (Lebon et al .…”

Section: Resultsmentioning

confidence: 99%

Section: Atomic-scale Order and Sample Micro-structure Probed By Atr-mentioning

confidence: 99%

Assessing bone transformation in late Miocene and Plio‐Pleistocene deposits of Kenya and South Africa

Aufort

Gommery²,

Gervais

et al. 2019

Archaeometry

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show abstract

“…Despite the strong HCl demineralization treatment, it appears that some phosphate remained in the samples. It has been shown experimentally and theoretically that variation in the phosphate bands derived from ATR FTIR of bone can be affected by bone collagen content, with low-frequency symmetry of the phosphate peaks more apparent in bone containing lower amounts of collagen (Aufort et al, 2018). The observation of sharper, more symmetric phosphate peaks in the Centrosaurus bone compared to the younger bone might suggest lower relative collagen content.…”

Section: Discussionmentioning

confidence: 99%

Cretaceous dinosaur bone contains recent organic material and provides an environment conducive to microbial communities

Saitta

Liang

Lau

et al. 2019

eLife

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Fossils were thought to lack original organic molecules, but chemical analyses show that some can survive. Dinosaur bone has been proposed to preserve collagen, osteocytes, and blood vessels. However, proteins and labile lipids are diagenetically unstable, and bone is a porous open system, allowing microbial/molecular flux. These ‘soft tissues’ have been reinterpreted as biofilms. Organic preservation versus contamination of dinosaur bone was examined by freshly excavating, with aseptic protocols, fossils and sedimentary matrix, and chemically/biologically analyzing them. Fossil ‘soft tissues’ differed from collagen chemically and structurally; while degradation would be expected, the patterns observed did not support this. 16S rRNA amplicon sequencing revealed that dinosaur bone hosted an abundant microbial community different from lesser abundant communities of surrounding sediment. Subsurface dinosaur bone is a relatively fertile habitat, attracting microbes that likely utilize inorganic nutrients and complicate identification of original organic material. There exists potential post-burial taphonomic roles for subsurface microorganisms.

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“…related to electrostatic interactions between apatite particles and therefore depending on porosity, grain size and shapes of particles. In contrast, the position and line shape of weaker and narrower bands, such as the ν 1 PO 4 band, are less affected by these electrostatic effects and are thus expected to provide a better insight into the short-range order of the crystal structure (Balan et al, 2011;Aufort et al, 2016Aufort et al, , 2018Aufort et al, , 2019. However, the overlap of the ν 1 PO 4 band with the stronger ν3 PO4 band in the diamond ATR spectrum significantly affects the line shape of the ν 1 PO 4 band.…”

Section: Atr-ftir Spectrum Of Bone Samplesmentioning

confidence: 99%

Atomic scale transformation of bone in controlled aqueous alteration experiments

Aufort

Gervais

Ségalen

et al. 2019

Palaeogeography, Palaeoclimatology, Palaeoecology

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The chemical and isotopic compositions of biogenic apatite are important geochemical markers, which can suffer modifications during fossilisation. Compared with modern ones, fossil apatites generally exhibit variations in carbonate content, enrichment in fluorine, incorporation of trace elements and an increase in crystallinity parameters. Detailed understanding of these transformations induced by fossilisation should help assess the preservation of geochemical records in apatites. In this contribution, we investigate the transformation of modern bone altered under controlled conditions. Modern bone samples were soaked in aqueous solutions of neutral to alkaline pH (9-10) for one and three weeks at various temperatures (20 and 70 °C) and experiments were duplicated in fluorine-free and in 10-2 M NaF solutions. Bone transformation was monitored through the modifications of chemical (F, Ca, P) and isotopic (δ 13 C, δ 18 Oc, δ 18 Op) composition as well as using vibrational (ATR-FTIR, Raman) and solidstate (1 H, 13 C, 19 F) NMR spectroscopies. The observed modifications sustain a transformation mechanism through partial dissolution of biogenic apatite and precipitation of secondary apatite. This transformation occurs irrespective of the presence or absence of fluorine and leads to the formation of carbonate-bearing fluorapatite or carbonate-bearing hydroxylapatite, respectively. The fraction of secondary apatite seems to be limited to ~60 %, suggesting that its formation has a protecting role against further dissolution of the primary apatite. The observation of clumped (CO 3 2-, F-) defect in the structural B-site of some samples as well as perturbation of the isotopic compositions attest to carbonate incorporation in the secondary apatite. Although the incorporation of fluoride ions can serve as a probe revealing dissolutionrecrystallisation of bone, the present study also underlines the difficulty to systematically relate mineralogical transformations to an open-system behaviour in bioapatite.

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Macroscopic electrostatic effects in ATR-FTIR spectra of modern and archeological bones

Cited by 13 publications

References 25 publications

Assessing bone transformation in late Miocene and Plio‐Pleistocene deposits of Kenya and South Africa

Assessing bone transformation in late Miocene and Plio‐Pleistocene deposits of Kenya and South Africa

Cretaceous dinosaur bone contains recent organic material and provides an environment conducive to microbial communities

Atomic scale transformation of bone in controlled aqueous alteration experiments

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