Photo: the Hrazdan valley around the village of Karashamb (the houses to the left). The meandering course of the River Hrazdan can clearly be seen, while the rocks in the centre of the photograph are basalts originally erupted as lava by volcanoes in the Gegham range.
Posted 12 July 2016
This blog begins, appropriately, in Yerevan, the capital of the Republic of Armenia. The city will be the base for a team of scientists carrying out the first season of fieldwork for the Pleistocene Archaeology, Geochronology and Environment of the Southern Caucasus – or PAGES – project.
The project website – www.winchester.ac.uk/PalaeoArmenia – provides details of the background to and aims of PAGES, but suffice to say that over the next three years we will seek to understand when, how and why early humans (members of the genus Homo in biological taxonomic terms) expanded from their evolutionary origin in Africa to the Southern Caucasus (modern day Armenia, Azerbaijan and Georgia), and from there to Eurasia.
The Southern Caucasus is of huge importance to the human evolutionary story as the find spot of the earliest human fossil (1.8 million years ago) outside Africa, at the Georgian site of Dmanisi, and the location of the earliest evidence of advanced human behaviour (325 thousand years ago) at Nor Geghi, Armenia.
Many academic disciplines contribute to the study of our early ancestors and therefore the PAGES team includes archaeologists, but also scientists from a broad range of Earth science backgrounds including volcanology, geochronology and palaeobiology. The project commences tomorrow with a survey of the Hrazdan valley between the northern suburbs of Yerevan and the village of Solak 26 km to the north-east (the meandering course of the river mean that approximately 40 km will actually be surveyed, largely on foot).
Over the coming month we will map the geology of the area, focussing especially on that of the Pleistocene (2.5 million to 11.5 thousand years ago). Volcanoes in the Gegham range to the east and the Arailer volcano to the west have erupted multiple times during this time interval and have filled the valley with lava and pyroclastic debris. In the intervening time between eruptions the Hrazdan river flowed through the valley, while lakes also developed in the lea of dams that were formed by the solidified lava. The floodplains of the former, the margins of the latter and the availability of obsidian (a volcanic glass, that can be worked into extremely sharp tools) would have made the valley very attractive to Palaeolithic humans.
As we map the geology therefore we will be searching for archaeological sites that we expect to find in former soils sandwiched between basalt layers (i.e. the solidified lavas). Indeed the basalts are of particularly importance for the project as their age can be determined using the Argon-Argon (40Ar/39Ar) dating technique (the riverine and lake sediments in which the archaeological sites will sit are much more difficult to date), so we will be collecting a series of 1kg blocks of rock to provide us with a chronology.
Tomorrow we commence, and over the next few weeks of fieldwork we will provide regular updates of our discoveries as we make them. We will also explain the techniques we are employing and how our interpretations change as the work progresses. In posts subsequent to the present fieldwork, we will share early results of the laboratory work on the samples we have collected. Thus over the course of the project this blog will tell the story of PAGES, a scientific investigation of early humans at the key geographic 'crossroads' between Africa, Europe and Asia.
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About the author
Dr Keith Wilkinson is Reader in Environmental Archaeology at the University of Winchester and Principal Investigator of the PAGES project.