Browsing by Author "Davara, Javier"
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- Compound-specific carbon isotope analysis of short-chain fatty acids from pine tissues: characterizing paleo-fire residues and plant exudatesPublication . Jambrina-Enríquez, Margarita; de Vera, Caterina Rodríguez; Davara, Javier; Herrera-Herrera, Antonio V.; Mallol, CarolinaDifferent types of plant tissues and resin can account for the wax lipids found in sedimentary contexts and archaeological samples. Consequently, there is increasing research to characterize the fatty acid carbon isotope ratios of different plant anatomical parts and their plant exudates (resin). With the aim to explore isotopic differences between plant tissues, state of the fine organic matter, effect of thermal degradation, and to identify plant residues we measured the δ13C values of short-chain fatty acids (δ13C16:0 and δ13C18:0) in: i) dead and fresh (collected and immediately dried) pine needles and branches (Pinus canariensis) and pine resin from laboratory-controlled heating experiments and ii) sediment and charred pine tissue samples from a wild pine forest fire. Our results are compared to previously published experimental open-air fire experiments and pine-fuelled archaeological combustion features. We found that for both fatty acid types, there are differences in δ13C signatures among anatomical parts and initial moisture content. These data allow us to characterize the isotopic signature of pine tissue and the effect of degradation on isotopic biomarkers, as well as to estimate combustion temperatures in pine-fuelled anthropogenic fires.
- Enhanced functional data retrieval from palaeolithic stone tools by lipid analysisPublication . Davara, Javier; Hernández, Cristo M.; Carrizo, Daniel; Herrera-Herrera, Antonio V.; Iriarte, Eneko; Mallol, CarolinaDespite the great potential of lipid biomarkers in archaeological science, their analysis in stone tools has been overlooked. The lipid retention capacity of Palaeolithic stone tools, along with the potential utility of the biomarkers they may harbour as a functional proxy, remains largely unknown. Here, we extracted lipid biomarkers from flint flakes and limestone pebbles from the Middle Palaeolithic site of El Salt (SE Spain) and analysed them using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Adjacent sediments were also analysed for comparison. We provide evidence that Palaeolithic stone tools preserve a diverse array of lipid biomarkers including fatty acids, n-alkanols, sterols and terpenoids, the analysis of which allowed us to determine whether the tools were used and/or hafted. The isotopic characterization of individual fatty acids preserved on tools’ working edges enabled us to identify lithic residues as fats resulting from the processing of ruminant animal species, or as lipids from non-ruminant animal and/or plant taxa. This introduces into functional studies a novel approach that adds taxonomic resolution and complements current techniques such as use-wear and micro-residue analyses. Our findings highlight the remarkable preservation potential of biomolecular remains within the Palaeolithic record and underscore the importance of exploring them in different kinds of materials and contexts.
- Fuel sources, natural vegetation and subsistence at a high-altitude aboriginal settlement in Tenerife, Canary Islands: Microcontextual geoarchaeological data from Roques de García RockshelterPublication . Tomé, Laura; Jambrina-Enríquez, Margarita; Égüez, Natalia; Herrera-Herrera, Antonio V.; Davara, Javier; Marrero Salas, Efraín; Arnay de la Rosa, Matilde; Mallol, CarolinaHigh-altitude island environments, with their characteristic strong seasonal contrast and limited resources, are challenging contexts for human subsistence. However, although archaeological contexts in this kind of setting hold great potential to explore the diversity of human biological and cultural adaptations, such sites are rare. In this paper, we present the results of a microcontextual geoarchaeological study carried out at Rogues de Garcia Rockshelter, the highest altitude cave archaeological site in the Canary Islands (Spain). The site was inhabited by the aboriginal population of the island and has yielded a rich archaeological context derived from combustion activity. We carried out soil micromorphology to characterize site function and lipid biomarker analysis to investigate the natural and anthropogenic organic record. Our data indicate that the aboriginal groups that occupied the site kept goats with them (in the rockshelter) and probably used Juniperus turbinata (sabina) wood, a current distant fuel source. These results suggest that the aboriginal societies of Tenerife occupied the highlands regularly, taking their herds and firewood with them. Further research is necessary to explore the use and exploitation of fuel sources, the seasonality of these occupations and their differences with lowland sites.
- Pyrotechnology and lipid biomarker variability in pine tar productionPublication . Davara, Javier; Jambrina-Enríquez, Margarita; Rodríguez de Vera, Caterina; Herrera-Herrera, Antonio V.; Mallol, CarolinaTar or pitch produced from pine resin and wood played an important role in the past as an adhesive, waterproofing and medicinal product. However, the formation and biomolecular composition of pine tar produced only from resin under different combustion conditions (i.e., temperature and oxygen availability during heating) has not been as widely investigated as pine tar produced by dry distillation of wood or birch bark tar, for which an extensive literature is available. This lack of information hampers technological interpretations of biomolecular data obtained from organic residue analyses of archaeological pine tar products. In this study, we performed controlled laboratory heating sequences with pine resin (Pinus canariensis) at 150, 250, 350 and 450 oC under both oxygenated and oxygen-limited conditions, and analyzed the products using gas chromatography-mass spectrometry (GC-MS). A control unheated resin sample was also analysed. We found that the formation of pine tar from resin occurs around 250-350 oC under both oxygenated and oxygen-limited atmospheres. We also present and discuss the lipid biomarkers of pine resin and its combustion products according to changes in temperature and oxygen availability. Our reference data provide new information for the biomolecular identification of archaeological pine tar products and show potential for shedding light on the conditions in which tar was manufactured by ancient populations in different contexts.