For a long chronology of the Early Upper Paleolithic in Europe

swabian aurignacien

 

This are  typical Aurignacian tools from the Swabian Aurignacian from my collection. Once assumed to be relatively young, this Aurignacian is now dated among the earliest Upper Paleolithic in Europe.

C-14 Measurements are traditionally made by counting the radioactive decay of individual carbon atoms by gas proportional counting or by liquid scintillation counting. Such measurements need samples of sufficient size (several grams of carbon). The sensitivity of C-14 dating has been greatly increased by the use of accelerator mass spectrometry (AMS). With this technique C-14 atoms can be detected and counted directly, as opposed to detecting radioactive decay. Radiocarbon AMS samples are prepared by completely burning the sample, collecting the resulting carbon dioxide, and reducing it to a solid carbon target for sputtering atomic carbon ions into the mass spectrometer. This method allows dating samples containing only a few milligrams of carbon and therefore has a lower risk for being biased by mixed samples.

Recent developments in the purification of bone collagen by advanced methods of “ultrafiltration” pre-treatment have made it possible to remove far younger contaminant carbon from bone samples than previously, which has already had important chronological implications for a number European sites, producing higher ages on bone specimens previously dated without this pre-treatment.  For now we must accept that an unknown proportion of radiocarbon results measured in the past may be unreliable and in the case of many bone samples (much) too young. On the other hand in the absence of an agreed standard pre-treatment procedure for bone samples and due to incomplete protocols between different laboratories for sample carbon content and carbon–nitrogen ratio, it is often difficult to evaluate the reliability of the dating results.

Radiocarbon (C-14) dates are always reported either as “percent modern” or years “before present” (BP). The first indicates the proportion of radiocarbon atoms in the sample as compared to samples modern in 1950. The second is directly derived from this on the assumption that the half-life of radiocarbon is 5568 years and the amount of radiocarbon in the atmosphere has been constant. Calibration of radiocarbon determinations in principle tries to determine the calendar age of a sample by correlating its raw C-14 age (BP) with calendric measurements made with other independent methods (for example varve chronology, marine sediments, tree ring data). The calibrated data  are assigned as: cal BC. Actually,  the problem with calibration at the moment is, that it is performed differently in different laboratories. According to my experience in calibration of physical systems  I do not doubt, that such problems will be overcome during the next years and that calibration is the only way to make local chronologies directly comparable with each other.

Approximately 39,3. k.a. cal BP, a massive volcanic eruption took place in the Phlegraean Fields, in central Italy, dated with high precision by A-40/A-39, spewing a plume of ash across large areas of south-central and Eastern Europe. The eruption deposits of this event are known as Campanian Ignimbrite (CI) Y-5 tephra. The (CI) Y-5 tephra has a unique signature and can serve as major chrono-stratigraphic marker independently of the C-14 chronology.  The eruption event precedes the Heinrich (H) 4 event in the Greenland ice record at  39,3 k.a. cal BP, which is characterized by a very dry and cold climate.

Wherever the (CI) Y-5 tephra marker is present (South East Europe), the classic Aurignacian consistently overlies the Campanian Ignimbrite. In these parts of Europe the classic Aurignacian therefore seems to be relative young. The Mediterranean Protoaurignacian (at Castelcivita) and Uluzzian (at Castelcivita and Cavallo) and the “Transitional” Paleolithic industries of the Kostenki area (loci 14 and 17) are found below the tephra and must therefore be older than 39 k.a. cal BP. These data are affirmed by the fact that pretreated-AMS dated-C-14 samples at of the Protoaurignacian in Italy  situate this techno complex at ca. 41-40 k.a. cal BP and the Uluzzian at 43 to 41 ka cal BP.

In other parts of Europe the situation is different: Most importantly pretreated-AMS dated-C-14 samples now indicate the presence of an early Aurignacian in S/W- and Middle Europe before the H4 event at the Geißenklösterle, Abri Pataud and at Les Cottés. It seems that the classic Aurignacian in these areas began much earlier than we suggested before!

For the implications of a long chronology on the the EUP of Moravia please look on Petr Škrdla`s talk presented on Gepaard 2013 meeting at: http://www.iabrno.cz/~skrdla/EUP.htm

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