Limits of calcium isotopes diagenesis in fossil bone and enamel

Pierre-Jean Dodat; Jeremy E. Martin; Sébastien Olive; Auguste Hassler; Emmanuelle Albalat; Jean-Renaud Boisserie; Gildas Merceron; Antoine Souron; Bruno Maureille; Vincent Balter

doi:10.1016/j.gca.2023.04.012

Limits of calcium isotopes diagenesis in fossil bone and enamel

Pierre-Jean Dodat, Jeremy E. Martin, Sébastien Olive, Auguste Hassler, Emmanuelle Albalat, Jean-Renaud Boisserie, Gildas Merceron, Antoine Souron, Bruno Maureille, Vincent Balter^* (Corresponding Author)

^*Corresponding author for this work

Archaeology

Research output: Contribution to journal › Article › peer-review

Abstract

Diagenesis has been recognized for decades to significantly alter the trace elements biogenic signatures in fossil tooth enamel and bone that are routinely used for paleobiological and paleoenvironmental reconstructions. This signature is modified during diagenesis according to a complex continuum between two main processes, addition and substitution. For an additive-like, or early diagenesis, the trace elements biogenic profiles can be restored by leaching secondary minerals, but this technique is inefficient for a substitutive-like, or extensive diagenesis for which secondary trace elements are incorporated into the biogenic mineral. This scheme is however unclear for Ca, the major cation in tooth enamel and bone hydroxylapatite, whose stable isotope composition (δ44/42Ca) also conveys biological and environmental information. We present a suite of leaching experiments for monitoring δ44/42Ca values in artificial and natural fossil enamel and bone from different settings. The results show that enamel δ44/42Ca values are insensitive to an additive-like diagenesis that involves the formation of secondary Ca-carbonate mineral phases, while bone shows a consistent offset toward 44Ca-enriched values, that can be restored to the biogenic baseline by a leaching procedure. In the context of a substitutive-like diagenesis, bone exhibits constant δ44/42Ca values, insensitive to leaching, and shows a REE pattern symptomatic of extensive diagenesis. Such a REE pattern can be observed in fossil enamel for which δ44/42Ca values are still fluctuating and follow a trophic pattern. We conclude that Ca isotopes in fossil enamel are probably not prone to extensive diagenesis and argue that this immunity is due to the very low porosity of enamel that cannot accommodate enough secondary minerals to significantly modify the isotopic composition of the enamel Ca pool.

Original language	English
Pages (from-to)	45-50
Number of pages	6
Journal	Geochimica et Cosmochimica Acta
Volume	351
Early online date	5 May 2023
DOIs	https://doi.org/10.1016/j.gca.2023.04.012
Publication status	Published - 15 Jun 2023

Bibliographical note

Acknowledgements
Pierre-Jean Dodat received financial supports from the CNRS 80|PRIME program and Research Program of the Nouvelle Aquitaine Region: Isotopes du calcium et anthropobiologie au Paléolithique moyen, convention n° 2019-1R40208. Sébastien Olive received funding from Fonds de la recherche scientifique (FNRS) and the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 101032456-TNT. Kani Bayez, Gaël Clément, Cécilia Cousin, Valentin Fischer, Annelise Folie, Vincent Mistrot, Emmanuel Robert, and the Omo Group Research Expedition (OGRE) are thanked for helping with the processing of fossil samples. Sampling authorization was delivered to the OGRE by the Ethiopian Heritage Authority/National Museum of Ethiopia, and a fossil sampling session in Addis Ababa was funded by the project ANR-17-CE27-0002 ‘DIET-Scratches’. We thank two anonymous reviewers and the Associate Editor Adrian Immenhauser for their in-depth reviews and constructive comments that greatly improved the quality of this article.

Keywords

Calcium Isotope
Fossil Bone
Fossil Enamel
Diagenesis

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10.1016/j.gca.2023.04.012

Cite this

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title = "Limits of calcium isotopes diagenesis in fossil bone and enamel",

abstract = "Diagenesis has been recognized for decades to significantly alter the trace elements biogenic signatures in fossil tooth enamel and bone that are routinely used for paleobiological and paleoenvironmental reconstructions. This signature is modified during diagenesis according to a complex continuum between two main processes, addition and substitution. For an additive-like, or early diagenesis, the trace elements biogenic profiles can be restored by leaching secondary minerals, but this technique is inefficient for a substitutive-like, or extensive diagenesis for which secondary trace elements are incorporated into the biogenic mineral. This scheme is however unclear for Ca, the major cation in tooth enamel and bone hydroxylapatite, whose stable isotope composition (δ44/42Ca) also conveys biological and environmental information. We present a suite of leaching experiments for monitoring δ44/42Ca values in artificial and natural fossil enamel and bone from different settings. The results show that enamel δ44/42Ca values are insensitive to an additive-like diagenesis that involves the formation of secondary Ca-carbonate mineral phases, while bone shows a consistent offset toward 44Ca-enriched values, that can be restored to the biogenic baseline by a leaching procedure. In the context of a substitutive-like diagenesis, bone exhibits constant δ44/42Ca values, insensitive to leaching, and shows a REE pattern symptomatic of extensive diagenesis. Such a REE pattern can be observed in fossil enamel for which δ44/42Ca values are still fluctuating and follow a trophic pattern. We conclude that Ca isotopes in fossil enamel are probably not prone to extensive diagenesis and argue that this immunity is due to the very low porosity of enamel that cannot accommodate enough secondary minerals to significantly modify the isotopic composition of the enamel Ca pool.",

keywords = "Calcium Isotope, Fossil Bone, Fossil Enamel, Diagenesis",

author = "Pierre-Jean Dodat and Martin, {Jeremy E.} and S{\'e}bastien Olive and Auguste Hassler and Emmanuelle Albalat and Jean-Renaud Boisserie and Gildas Merceron and Antoine Souron and Bruno Maureille and Vincent Balter",

note = "Acknowledgements Pierre-Jean Dodat received financial supports from the CNRS 80|PRIME program and Research Program of the Nouvelle Aquitaine Region: Isotopes du calcium et anthropobiologie au Pal{\'e}olithique moyen, convention n° 2019-1R40208. S{\'e}bastien Olive received funding from Fonds de la recherche scientifique (FNRS) and the European Union{\textquoteright}s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 101032456-TNT. Kani Bayez, Ga{\"e}l Cl{\'e}ment, C{\'e}cilia Cousin, Valentin Fischer, Annelise Folie, Vincent Mistrot, Emmanuel Robert, and the Omo Group Research Expedition (OGRE) are thanked for helping with the processing of fossil samples. Sampling authorization was delivered to the OGRE by the Ethiopian Heritage Authority/National Museum of Ethiopia, and a fossil sampling session in Addis Ababa was funded by the project ANR-17-CE27-0002 {\textquoteleft}DIET-Scratches{\textquoteright}. We thank two anonymous reviewers and the Associate Editor Adrian Immenhauser for their in-depth reviews and constructive comments that greatly improved the quality of this article.",

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T1 - Limits of calcium isotopes diagenesis in fossil bone and enamel

AU - Dodat, Pierre-Jean

AU - Martin, Jeremy E.

AU - Olive, Sébastien

AU - Hassler, Auguste

AU - Albalat, Emmanuelle

AU - Boisserie, Jean-Renaud

AU - Merceron, Gildas

AU - Souron, Antoine

AU - Maureille, Bruno

AU - Balter, Vincent

N1 - Acknowledgements Pierre-Jean Dodat received financial supports from the CNRS 80|PRIME program and Research Program of the Nouvelle Aquitaine Region: Isotopes du calcium et anthropobiologie au Paléolithique moyen, convention n° 2019-1R40208. Sébastien Olive received funding from Fonds de la recherche scientifique (FNRS) and the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 101032456-TNT. Kani Bayez, Gaël Clément, Cécilia Cousin, Valentin Fischer, Annelise Folie, Vincent Mistrot, Emmanuel Robert, and the Omo Group Research Expedition (OGRE) are thanked for helping with the processing of fossil samples. Sampling authorization was delivered to the OGRE by the Ethiopian Heritage Authority/National Museum of Ethiopia, and a fossil sampling session in Addis Ababa was funded by the project ANR-17-CE27-0002 ‘DIET-Scratches’. We thank two anonymous reviewers and the Associate Editor Adrian Immenhauser for their in-depth reviews and constructive comments that greatly improved the quality of this article.

PY - 2023/6/15

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N2 - Diagenesis has been recognized for decades to significantly alter the trace elements biogenic signatures in fossil tooth enamel and bone that are routinely used for paleobiological and paleoenvironmental reconstructions. This signature is modified during diagenesis according to a complex continuum between two main processes, addition and substitution. For an additive-like, or early diagenesis, the trace elements biogenic profiles can be restored by leaching secondary minerals, but this technique is inefficient for a substitutive-like, or extensive diagenesis for which secondary trace elements are incorporated into the biogenic mineral. This scheme is however unclear for Ca, the major cation in tooth enamel and bone hydroxylapatite, whose stable isotope composition (δ44/42Ca) also conveys biological and environmental information. We present a suite of leaching experiments for monitoring δ44/42Ca values in artificial and natural fossil enamel and bone from different settings. The results show that enamel δ44/42Ca values are insensitive to an additive-like diagenesis that involves the formation of secondary Ca-carbonate mineral phases, while bone shows a consistent offset toward 44Ca-enriched values, that can be restored to the biogenic baseline by a leaching procedure. In the context of a substitutive-like diagenesis, bone exhibits constant δ44/42Ca values, insensitive to leaching, and shows a REE pattern symptomatic of extensive diagenesis. Such a REE pattern can be observed in fossil enamel for which δ44/42Ca values are still fluctuating and follow a trophic pattern. We conclude that Ca isotopes in fossil enamel are probably not prone to extensive diagenesis and argue that this immunity is due to the very low porosity of enamel that cannot accommodate enough secondary minerals to significantly modify the isotopic composition of the enamel Ca pool.

AB - Diagenesis has been recognized for decades to significantly alter the trace elements biogenic signatures in fossil tooth enamel and bone that are routinely used for paleobiological and paleoenvironmental reconstructions. This signature is modified during diagenesis according to a complex continuum between two main processes, addition and substitution. For an additive-like, or early diagenesis, the trace elements biogenic profiles can be restored by leaching secondary minerals, but this technique is inefficient for a substitutive-like, or extensive diagenesis for which secondary trace elements are incorporated into the biogenic mineral. This scheme is however unclear for Ca, the major cation in tooth enamel and bone hydroxylapatite, whose stable isotope composition (δ44/42Ca) also conveys biological and environmental information. We present a suite of leaching experiments for monitoring δ44/42Ca values in artificial and natural fossil enamel and bone from different settings. The results show that enamel δ44/42Ca values are insensitive to an additive-like diagenesis that involves the formation of secondary Ca-carbonate mineral phases, while bone shows a consistent offset toward 44Ca-enriched values, that can be restored to the biogenic baseline by a leaching procedure. In the context of a substitutive-like diagenesis, bone exhibits constant δ44/42Ca values, insensitive to leaching, and shows a REE pattern symptomatic of extensive diagenesis. Such a REE pattern can be observed in fossil enamel for which δ44/42Ca values are still fluctuating and follow a trophic pattern. We conclude that Ca isotopes in fossil enamel are probably not prone to extensive diagenesis and argue that this immunity is due to the very low porosity of enamel that cannot accommodate enough secondary minerals to significantly modify the isotopic composition of the enamel Ca pool.

KW - Calcium Isotope

KW - Fossil Bone

KW - Fossil Enamel

KW - Diagenesis

U2 - 10.1016/j.gca.2023.04.012

DO - 10.1016/j.gca.2023.04.012

M3 - Article

SN - 0016-7037

VL - 351

SP - 45

EP - 50

JO - Geochimica et Cosmochimica Acta

JF - Geochimica et Cosmochimica Acta

ER -

Limits of calcium isotopes diagenesis in fossil bone and enamel

Abstract

Bibliographical note

Keywords

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