Horizons of volcanic tephra were repeatedly deposited across Mediterranean and Eastern Europe throughout the Pleistocene, providing a distinct chronological marker. One of these main tephra events, the Campanian Ignimbrite (CI), took place around the time of the Middle to Upper Palaeolithic transition. Its influence on Neanderthal and early modern human populations and cultural changes has been heavily debated. A new review paper, published in Quaternary Science Reviews, now plays down the impact of this eruption based on an integrated review of stratigraphic, archaeological and chronological data.
The authors first discuss the utility of tephra and point out that the Argon method used to date tephra can be calibrated in different ways and hence a larger standard deviation should be taken into account. They therefore say that the CI event could have taken place at any point in the 40.9 to 37.3 ka time range. They then discuss the problems related to trying to reconstruct the MUP transition based solely on stratigraphic or radiometric data, especially when not integrated on a regional scale. So far the CI tephra has been unambiguously identified at 11 archaeological sequences. At some other sites a tephra is present but has not yet been geochemically fingerprinted, and hence cannot be excluded to relate to another volcanic event, such as the Codola eruption around 33 ka cal BP.
At the sites where archaeological material and the CI tephra deposit are present, the latter seems to cap Uluzzian (e.g. Klissoura), Bachokirian (e.g. Temnata) and Proto-Aurignacian (e.g. Serino and Castelcivita) cultural layers. At some sites it caps an archaeological layer which cannot be unambiguously assigned to an archaeological entity. Above the CI horizon most commonly Early Aurignacian or sterile deposits are found.
Next, the authors integrate this stratigraphic data with selected, reliable, radiocarbon dates, concluding that the Proto-Aurignacian and Uluzzian were distinct in time. They describe the Uluzzian as made by Neanderthals and representing a local evolution from the late Mousterian, and the Proto-Aurignacian as intrusive and made by modern or Neanderthal-modern hybrid populations. When further integrating dates for the Early Aurignacian, they conclude that there is a high probability that Early Aurignacian populations were already present in Europe before the CI event. Because none of these cultural changes can be linked directly to the CI event, they conclude that the CI eruption and its environmental impacts played no role in the emergence of the Early Aurignacian.
Crucial in building these models, and also acknowledged by the authors, is the current low numbers of sites with a secure identification of the CI horizon. Moreover, the late Mousterian in the region is still badly understood as well. Therefore, further geochemical fingerprinting and more sites with well understood stratigraphic sequences are a must for in-depth investigations of the impact of this volcanic eruption on cultural changes across the MUP transition in Southern Europe.
Full reference: d’Errico, F. and Banks, W. in press. Tephra studies and the reconstruction of Middle-to-Upper Paleolithic cultural trajectories. Quaternary Science Reviews. DOI: 10.1016/j.quascirev.2014.05.014