Elemental distribution and speciation of Sr in bones to improve growth model in palaeontology

Almost all skeletal tissues record visible marks such as Lines of Arrested Growth (LAGs) that form annually during the unfavourable season. The identification of LAGs serves in palaeontology to calculate individual ages and to model the growth of organisms. However, sometimes bone growth slows down without ceasing, which implies LAGs are not systematically formed in bone tissue. Accordingly, this leads to the construction of inaccurate growth models. However, these seasonal modulations in bone growth are produced by internal physiological changes in the body, so that what is not recorded structurally could nevertheless be recorded chemically. Previous experiment (ESRF BM23 beamline ES1272) revealed for the first time in fossil dinosaur bones that these LAGs corresponded to marked enrichments in strontium (Sr). In order to validate these data and propose a biological model for Sr incorporation into bone tissue, it is crucial to perform the same analyses to bones of modern vertebrate.