Preservation assessment of Miocene–Pliocene tooth enamel from Tugen Hills (Kenyan Rift Valley) through FTIR, chemical and stable-isotope analyses

Roche, Damien; Ségalen, Loïc; Balan, Etienne; Delattre, Simon

doi:10.1016/j.jas.2010.01.029

Cited by 64 publications

(63 citation statements)

References 59 publications

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“…The FBC4Me enamel sample seems to sit between these two extremes. The most relevant FTIR indices for bioapatite have been calculated for the biological samples (for a review of these indices, see ) and are reported in Table , together with the same indices calculated in the inorganic samples in this study, for comparison. A brief explanation of the significance of these indices is also given.…”

Section: Resultsmentioning

confidence: 99%

“…FTIR spectroscopy uses the capacity of a material to absorb the energy of an irradiating infrared beam at characteristic frequencies of its functional groups. For carbonated apatite, these functional groups are, for example, PO 4 and CO 3 and OH in the different mineralogical positions and, in the case of bones and dentine bioapatite, also the frequencies associated with the collagen amide (NH 2 ) and water groups …”

Section: Methodsmentioning

confidence: 99%

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A comparison of pretreatment methods for the analysis of phosphate oxygen isotope ratios in bioapatite

Grimes

Pellegrini

2012

Rapid Comm Mass Spectrometry

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RATIONALE:The integrity of the biological phosphate oxygen isotope (d 18 O p ) signal is thought to be contingent upon the complete removal of competing sources of oxygen such as associated organic matter. A range of pretreatment methods to purify phosphate material from competing sources of oxygen has been reported, with contradictory evidence on the usefulness and efficiency of one or another. Yet, a systematic comparison of these techniques for bioapatite phosphate has not been conducted. METHODS: Chemical and thermal pretreatment techniques were tested for their effectiveness at removing organic matter and the likelihood that they modify original d 18 O values. The test was performed in inorganic (synthetic apatite and a phosphorite rock) and organic (bone and tooth tissues) phosphate materials for which we had an expectation of the actual original d 18 O p value. Analysis of nitrogen content (wt.%), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were employed. RESULTS: We detected variable efficiency at removing organic matter between pretreatment methods with no correlation to any specific structural change. The d 18 O p results showed considerable variation between samples pretreated with the different methods and the untreated samples, with a compositional range of up to 4.5 % in the bone samples. Variations of the d 18 O p values within error were found for tooth enamel, phosphorite rock and inorganic apatite. CONCLUSIONS: We recommend a cautious approach when interpreting and comparing d 18 O p data from bone samples treated with different pretreatment protocols. In general, the untreated samples seem to show d 18 O p values closer to the expected ones. According to our results, pretreatment is completely unnecessary in highly mineralized tissues. Copyright

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

A comparison of pretreatment methods for the analysis of phosphate oxygen isotope ratios in bioapatite

Grimes

Pellegrini

2012

Rapid Comm Mass Spectrometry

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“…Stable isotope compositions of biogenic apatites, and in particular the isotope composition (d 13 C, d 18 O) of structural carbonate groups, are widely used to reconstruct past climates, past environments and dietary preferences of vertebrates (e.g. Kohn and Cerling, 2002;Roche et al, 2010;Roche et al, 2013;Pack et al, 2013;Reynard and Balter, 2014). For example, the carbon stable isotope composition of carbonate-bearing bio-apatites reflects that of ingested food and is used to infer dietary preferences of vertebrates in a variety of paleoecological studies (Lee-Thorp and van der Merwe, 1987;Quade et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

Site-specific equilibrium isotopic fractionation of oxygen, carbon and calcium in apatite

Aufort

Ségalen

Gervais

et al. 2017

Geochimica et Cosmochimica Acta

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The stable isotope composition of biogenic apatite is an important geochemical marker that can record environmental parameters and is widely used to infer past climates, biomineralization processes, dietary preferences and habitat of vertebrates. In this study, theoretical equilibrium isotopic fractionation of oxygen, carbon and calcium in hydroxyapatite and carbonate-bearing hydroxyapatite is investigated using first-principles methods based on density-functional theory and compared to the theoretical isotopic fractionation properties of calcite, CO 2 and H 2 O. Considering the variability of apatite crystal-chemistry, special attention is given to specific contributions of crystal sites to isotopic fractionation. Significant internal fractionation is calculated for oxygen and carbon isotopes in CO 3 between the different structural sites occupied by carbonate groups in apatite (typically 7‰ for both 18 O/ 16 O and 13 C/ 12 C fractionation at 37°C). Compared with calcite-water oxygen isotope fractionation, occurrence of A-type substitution in apatite structure, in addition to the main B-type substitution, could explain the larger temperature dependence of oxygen isotope fractionation measured at low temperature between carbonate in apatite and water. Theoretical internal fractionation of oxygen isotopes between carbonate and phosphate in B-type carbonated apatite ($8‰ at 37°C) is consistent with experimental values obtained from modern and well-preserved fossil bio-apatites. Concerning calcium, theoretical results suggest a small fractionation between apatite and calcite (À0.17‰ at 37°C). Internal fractionation reaching 0.8‰ at 37°C occurs between the two Ca sites in hydroxyapatite. Furthermore, the Ca isotopic fractionation properties of apatite are affected by the occurrence of carbonate groups, which could contribute to the variability observed on natural samples. Owing to the complexity of apatite crystal-chemistry and in light of the theoretical results, measurements of site-specific isotopic fractionation properties could improve our understanding and the interpretation of isotopic records in apatites.

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“…This information is usually obtained from relative spectral intensities in the range of PO 4 bending vibrational modes ( 4 PO 4 ) and reported as an empirical "crystallinity" index (e.g. Shemesh 1990;Weiner and Bar-Yosef 1990;Surovell and Stiner 2001;Pucéat et al 2004;Trueman et al 2008;Roche et al 2010). The other type of information is related to the concentration and location of molecular species, such as carbonate groups, that are detected by specific vibrational bands (e.g.…”

Section: Introductionmentioning

confidence: 99%

Modeling the attenuated total reflectance infrared (ATR-FTIR) spectrum of apatite

et al. 2016

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Preservation assessment of Miocene–Pliocene tooth enamel from Tugen Hills (Kenyan Rift Valley) through FTIR, chemical and stable-isotope analyses

Cited by 64 publications

References 59 publications

A comparison of pretreatment methods for the analysis of phosphate oxygen isotope ratios in bioapatite

A comparison of pretreatment methods for the analysis of phosphate oxygen isotope ratios in bioapatite

Site-specific equilibrium isotopic fractionation of oxygen, carbon and calcium in apatite

Modeling the attenuated total reflectance infrared (ATR-FTIR) spectrum of apatite

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