Formation of Biphasic Hydroxylapatite-Beta Magnesium Tricalcium Phosphate in Heat Treated Salmonid Vertebrae

Abstract

Ichthyoarchaeological evidence is uncommon at ancient hunter-gatherer sites from various regions and timeframes. This research contributes to the development of microarchaeological techniques useful for identifying fishing economies in situations where classifiable bones are unavailable. Specifically, traces of heat altered bone mineral in domestic hearths are expected to provide markers for discarded fish remains. We used a series of laboratory incineration experiments to characterize the mineralogy of burned salmonid vertebrae. Fourier transform infrared spectroscopy and x-ray diffraction distinguished the formation of beta magnesium tricalcium phosphate (βMgTCP) at temperatures as low as 600 °C. Bones from a sample of game mammals and birds did not form this phase at temperatures below 1,000 °C. We propose that this neoformed mineral can serve as a proxy for hunter-gatherer salmonid fishing when typical ichthyoarchaeological evidence is absent. Using Fourier transform infrared spectroscopy, it will be possible to rapidly and inexpensively determine the presence of βMgTCP in fragmentary burned bone remains associated with combustion features. The occurrence of βMgTCP in archaeological hearth features will offer a new means of further evaluating the temporal, geographic, and cultural scope of salmonid harvesting. We also acknowledge the value of biphasic hydroxylapatite-βMgTCP recovered from Atlantic salmon vertebrae as a bioceramic.

Early Evidence for Northern Salmonid Fisheries Discovered using Novel Mineral Proxies

“…2B–D ; Supplementary Information 2A). The formation of these minerals primarily owes to the Ca 2+ deficient, Mg 2+ rich nature of the hydroxylapatite (HAp: Ca 10 (PO 4 ) 6 (OH) 2 ) mineral in these bones 16–30 . This finding demonstrated that new minerals formed in burned Atlantic salmonid bones can preserve in acidic northern archaeological contexts.…”

“…Dozens of black, brown, white, and grey particles of what appeared to be bone were selected for mineralogical analysis by FTIR. Several black bone particles (0.5–2 mm in diameter) were found to contain both WH and crystalline HAp (Figs 3, S2, S3D and Supplementary Information 2C) 16–19,30 . HAp crystallinity could not be assessed using the infrared splitting factor (IRSF), as the presence of WH bands distorted the phosphate (PO 4 ) v 4 band required to make the calculation (see Materials and Methods and Supplementary Information 2B).…”

“…HAp crystallinity could not be assessed using the infrared splitting factor (IRSF), as the presence of WH bands distorted the phosphate (PO 4 ) v 4 band required to make the calculation (see Materials and Methods and Supplementary Information 2B). However, both a leftward shift and split in the PO 4 v 3 infrared absorbance band were suggestive of somewhat crystalline HAp 16,24 . This confirmed that the examined particles are bone.…”

“…Burned fish bone fragments, however, may be preserved in the sediments comprising these combustion features. In a recent study we found that rare calcium-magnesium phosphate minerals form in salmonid bones burned at the relatively low temperatures typical of open wood-fuelled hearths (400–600 °C), and we postulated that these minerals have the potential to serve as proxy indicators for ancient salmonid fisheries 16 . The validity of this premise, however, relies on the preservation of burned salmonid bone fragments and associated neoformed minerals in acidic northern sediments.…”

Citotoxicidade in vitro de nanopartículas de fosfato tricálcico-β sintetizado via reação em estado sólido

“…A razão molar de Ca/P, calculada através do percentual atômico (Tabela 1), foi de 1,52. Segundo a literatura, o TCP-β apresenta razão molar de 1,50 [30,31,32,33,34], o que corrobora a formação da amostra desejada.…”