Compound-specific Radiocarbon dating

The application of biomolecular techniques to archaeological materials from the Balkans is providing valuable new information on the prehistory of the region. This is especially relevant for the study of the neolithisation process in SE Europe, which gradually affected the rest of the continent. Here, to answer questions regarding diet and subsistence practices in early farming societies in the central Balkans, we combine organic residue analyses of archaeological pottery, taxonomic and isotopic study of domestic animal remains and biomolecular analyses of human dental calculus. The results from the analyses of the lipid residues from pottery suggest that milk was processed in ceramic vessels. Dairy products were shown to be part of the subsistence strategies of the earliest Neolithic communities in the region but were of varying importance in different areas of the Balkan. Conversely, milk proteins were not detected within the dental calculus. The molecular and isotopic identification of meat, dairy, plants and beeswax in the pottery lipids also provided insights into the diversity of diet in these early Neolithic communities, mainly based on terrestrial resources. We also present the first compound-specific radiocarbon dates for the region, obtained directly from absorbed organic residues extracted from pottery, identified as dairy lipids.

This article presents the results of the first dedicated study of organic residues in Portugal, extracted from pottery excavated from Anta 1 de Val da Laje passage grave. We fully exploit the organic residue extract, to obtain information regarding the diet of the people and their relationship with the environment, the socio-economic aspects of an otherwise elusive society, and we also used a new methodology to obtain direct absolute dates for the pottery, the residue extract being the only datable organic material from the site. Our results suggest a community with diet based on terrestrial resources, that was fully benefitting from a range of domestic animals including their secondary products. We present the first direct evidence of not only meat consumption, but also milk and dairy production in Iberia. The compound specific radiocarbon dating methodology, opens a door to possibilities for investigating otherwise poorly dated archaeological phenomena in the Iberian Peninsula.

Molecular and isotopic investigation of lipids from soils filling several structures from an archaeological site located at Obernai (Alsace, NE France) has revealed the presence of miliacin, a triterpenoid marker
from Panicum miliaceum (broomcorn millet), indicating that this cereal was cultivated at the site. The concentration profiles of miliacin within silos and its detection in other archaeological structures (e.g., Gaulish pit) suggest that miliacin did not originate from cereals stored in the silos but rather came from remains of millet from cultivated soils which filled the silos after they were abandoned. Furthermore, the 14C age of miliacin isolated from a silo of the Second Iron Age was shown to be considerably older (Bronze Age) than the structure itself, revealing that the soil filling the silo therefore archived the molecular signature from past millet cropping, predating the digging of the silo. Thus, radiocarbon dating of the isolated miliacin allowed the timing of millet cropping to be determined, showing that it was established during the Bronze Age and the Roman Gaul period at Obernai. This is the first evidence of millet cultivation in Alsace dating back to the Bronze Age, bringing new perspectives on agricultural practices and past dietary practice in Eastern France. The combination of molecular studies and radiocarbon dating of individual lipids highlights the potential of hollow structures like silos and pits to act as ‘‘pedological traps”, recording information on past vegetation cover or agricultural practices from the surface horizons of surrounding soils that filled these structures after abandonment.

Existing radiocarbon ((14)C) dates on American mastodon (Mammut americanum) fossils from eastern Beringia (Alaska and Yukon) have been interpreted as evidence they inhabited the Arctic and Subarctic during Pleistocene full-glacial times (∼18,000 (14)C years B.P.). However, this chronology is inconsistent with inferred habitat preferences of mastodons and correlative paleoecological evidence. To establish a last appearance date (LAD) for M. americanum regionally, we obtained 53 new (14)C dates on 36 fossils, including specimens with previously published dates. Using collagen ultrafiltration and single amino acid (hydroxyproline) methods, these specimens consistently date to beyond or near the ∼50,000 y B.P. limit of (14)C dating. Some erroneously "young" (14)C dates are due to contamination by exogenous carbon from natural sources and conservation treatments used in museums. We suggest mastodons inhabited the high latitudes only during warm intervals, particularly the Last Interglacial [Marine Isotope Stage (MIS) 5] when boreal forests existed regionally. Our (14)C dataset suggests that mastodons were extirpated from eastern Beringia during the MIS 4 glacial interval (∼75,000 y ago), following the ecological shift from boreal forest to steppe tundra. Mastodons thereafter became restricted to areas south of the continental ice sheets, where they suffered complete extinction ∼10,000 (14)C years B.P. Mastodons were already absent from eastern Beringia several tens of millennia before the first humans crossed the Bering Isthmus or the onset of climate changes during the terminal Pleistocene. Local extirpations of mastodons and other megafaunal populations in eastern Beringia were asynchrononous and independent of their final extinction south of the continental ice sheets.

This research addresses the stability of bioapatite and collagen fractions of AMS dated steppe bison (Bison
priscus) teeth. Through the course of other research, 8 prehistoric bison molars were submitted for AMS
dating of fractions of collagen extracted from the dentine of each tooth. Because the teeth were well
preserved and collagen yields were relatively high during the initial analysis, it provided an opportunity
to further research differences between AMS dates produced on collagen from dentine and bioapatite fractions
from enamel. The specimens were recovered from late Quaternary sediments of the Lost Chicken
Creek drainage in east-central Alaska. All of the samples were very well preserved and gave high enough
yield of carbon from both fractions. The 14C/13C ratio was measured using 0.5 MV tandem AMS system.
The 14C age of the samples varied across age ranges between 17,360 ± 50 and 43,370 ± 300 noncalibrated
years BP. Such a wide range of ages allows us estimate the stability of each fraction in subarctic
permafrost conditions. The results of analyses have shown that 14C ages of bioapatite fraction are
rejuvenated as a result of isotopic exchange with the younger carbon from the soil solutions. The dating
of bioapatite from the samples collected in the boreal climate of Alaska is possible only with a certain correction
for the isotope fractionation.

Existing radiocarbon (14C) dates on American mastodon (Mammut
americanum) fossils from eastern Beringia (Alaska and Yukon) have been interpreted as evidence they inhabited the Arctic and
Subarctic during Pleistocene full-glacial times (∼18,000 14C years
B.P.). However, this chronology is inconsistent with inferred habitat
preferences of mastodons and correlative paleoecological evidence. To establish a last appearance date (LAD) for M. americium regionally, we obtained 53 new 14C dates on 36 fossils,
including specimens with previously published dates. Using collagen ultrafiltration and single amino acid (hydroxyproline) methods, these specimens consistently date to beyond or near the ∼50,000 y B.P. limit of 14C dating. Some erroneously “young” 14C dates are due to contamination by exogenous carbon from natural sources and conservation treatments used in museums. We suggest mastodons inhabited the high latitudes only during warm intervals, particularly the Last Interglacial [Marine Isotope Stage (MIS) 5] when boreal forests existed regionally. Our 14C dataset suggests that mastodons were extirpated from eastern Beringia during the MIS 4 glacial interval (∼75,000 y ago), following the ecological shift from boreal forest to steppe tundra. Mastodons thereafter became restricted to areas south of the continental ice sheets, where they suffered complete extinction ∼10,000 14C years B.P. Mastodons were already absent from eastern Beringia several tens of millennia before the first humans crossed the Bering Isthmus or the onset of climate changes during the terminal Pleistocene. Local extirpations of mastodons and other megafaunal populations in eastern Beringia were asynchrononous and independent of their final extinction south of the continental ice sheets.