Since 2008, an international team of researchers has been investigating the Middle and Upper Pleistocene archaeology (750,000 - 11,500 years ago) of the Hrazdan valley in central Armenia.
The research has comprised archaeological excavation of a previously known site (Lusakert 1), a geomorphological survey to reconstruct and date landscape change during the period and archaeological prospection to search for new Palaeolithic sites. By far the most important discovery in the last category is Nor Geghi 1 (NG1), photo. This unique locale is key to the understanding of hominin behaviourial change around 325,000 years ago (see below).
Geoarchaeological work carried out by staff at the University of Winchester has been an integral part of all aspects of the project and is the focus of this web page. The map below shows the location of the sites in relation to their surroundings.
The Hrazdan river is the sole drainage of Lake Sevan, the largest natural lake in the Caucasus. As the Hrazdan flows southwards towards its confluence with the Arax river south of Yerevan it cuts through a series of former lava flows (preserved in the geological record as basalts) from three volcanoes in the Gegham range. We have both mapped the lavas and investigated the deposits that are sandwiched between them. The latter are effectively fossilised surfaces of environments that existed prior to each volcanic eruption; they comprise lakes, river channels and floodplains. Given that volcanic deposits such as basalt can be dated with great precision using the 40Ar/39Ar technique, it is possible to reconstruct the chronology of landscape change in great detail. Although at the moment we have only dated the uppermost (latest) basalts, which are around 200,000 years old, we know from other work that the eruptive history of the western part of the Gegham range extends to around 550,000 BP (Lebedev et al. 2013).
Nor Geghi 1: the artefacts and the geoarchaeological context
The NG1 archaeological site comprises obsidian artefacts contained within a floodplain soil that outcrop beneath the latest Gegham lava and an earlier lava that we have 40Ar/39Ar-dated to around 440,000 BP. During excavations in 2008-09 we recovered almost 3000 artefacts from NG1, all made from the volcanic glass obsidian.
The significance of the artefacts is that they comprise both Acheulian (so-called Mode 2 e.g. handaxes) as well as Levallois (Mode 3) types. The latter is commonly considered to represent a significant behavioural and cognitive advance over the former as the final form of the Levallois tool (i.e. a flake) is only revealed following the final hammer blow. Prior to that it is entirely in the mind of the maker. In contrast, an Acheulian handaxe gradually and visibly takes form during manufacture. Photo: lithics from NG1. A: bifaces; B: Levallois cores. Photo Dan Adler.
The soil containing the NG1 artefacts was buried by further floodplain sediments and these contained tephra (i.e. volcanic ash) with a chemical composition different from that in the earlier floodplain. We were able to date the tephra, again using the 40Ar/39Ar technique, to around 308,000 BP, meaning that the artefacts must be older than this date but younger than 440,000 years ago. However, given that a soil with the mature development characteristics of that containing the artefacts could only have formed during the peak warmth of an interglacial, we have suggested that it dates to the 335 - 325,000 BP interval (i.e. during the Oxygen Isotope Stage 9c interglacial).
The geoarchaeological evidence suggests that the Acheulian and Levallois artefacts form part of a single coherent assemblage, which is therefore likely to have been made by a single hominin group. We have therefore interpreted the evidence to suggest that the Levallois was a gradual development from previous artefact technologies, probably by archaic hominin species. Our view is therefore contrary to the existing paradigm, which sees the Levallois as spreading with migrating hominins from outside the region.
The Hrazdan Gorge Palaeolithic Project is a collaboration with the University of Connecticut (Dr Daniel Adler) and the Institute of Archaeology and Ethnography, Yerevan (Dr Benik Yeritsyan, Boris Gasparian), while researchers from other universities in Armenia, the United Kingdom, Canada, Spain, the Netherlands, Germany, Ireland and the United States have made vital contributions. The 40Ar/39Ar dating reported here was undertaken by Dr Darren Mark of the NERC Argon Isotope Facility.
Funding for the project has been provided by the University of Connecticut, the UK Natural Environment Research Council (IP-1186-0510), the L.S.B. Leakey Foundation, the Irish Research Council and the University of Winchester.
Adler, D.S., Wilkinson, K.N., Blockley, S.P.E., Mark, D.F., Pinhasi, R., Schmidt-Magee, B.A, Yeritsyan, B., Nahapetyan, S., Mallol, C., Berna, F., Glauberman, P.J., Raczynski-Henk, Y., Wales, N., Cullen, V.L., Frahm, E., Jöris, O., Macloud, A., Smith, V.C. and Gasparian. B. (2014) Early Levallois Technology and the Transition from the Lower to Middle Palaeolithic in the Southern Caucasus. Science 345, 1609-1613.
Frahm, E., Feinberg, J.M., Schmidt-Magee, B.A., Wilkinson, K.N., Gasparyan, B., Yeritsyan, B., Karapetian, S., Meliksetian, K., Muth, M.J. and Adler, D.S. (2014) Sourcing geochemically identical obsidian: multiscalar magnetic variations in the Gutansar volcanic complex and implications for Palaeolithic research in Armenia. Journal of Archaeological Science 47, 164-178.
Adler, D.S., Yeritsyan, B. Wilkinson, K.N., Pinhasi, R., Bar-Oz, G., Nahapetyan, S., Bailey, R., Schmidt, B.A. Glauberman, P., Wales, N. and Gasparian. B. (2012) The Hrazdan Gorge Palaeolithic Project, 2008–2009. In Avetisyan, P. and Bobokhyan, A. (eds) Archaeology of Armenia in Regional Context, Proceedings of the International Conference dedicated to the 50th Anniversary of the Institute of Archaeology and Ethnography held on September 15-17, 2009 in Yerevan, Armenia. NAS RA Gitutyn Publishing house, Yerevan, 21–37
Lebedev, V.A., Chernyshev, I.V., Shatagin, K.N., Bubnov, S.N.,. Yakushev A.I. (2013) The Quaternary volcanic rocks of the Geghama Highland, Lesser Caucasus, Armenia: geochronology, isotopic Sr–Nd characteristics, and origin. Journal of Volcanology and Seismology 7, 204–229.