Luxor Part 2: Dr Angus Graham’s fieldwork
Last Wednesday, Essam and I had the pleasure to visit Dr Angus Graham, Director of the EES Theban Harbours and Waterscapes Survey project (in collaboration with Uppsala University and the Knut and Alice Wallenberg Foundation), and his team, on the West Bank of Luxor. Now in their fifth season, this important mission seeks to establish a geomorphological history of the Theban West Bank floodplain using geoarchaeological survey techniques, such as hand auguring (pictured above), percussion corer hand auguring and geophysical survey - including ERT (Electrical Resistivity Tomography) and GPR (Ground Penetrating Radar). Angus has already published some of the preliminary results of this work, which you can read more about in JEA 98, 99 and 100 and in EA 38 (here).
The first part of the morning was spent with Angus in the dig house, learning more about the treatment of the augured sediment samples. As opposed to usual archaeological excavations, which deal with 5 x 5 metre grid squares and stratigraphic layers revealing physical structures and/or objects, auguring in farmlands equates to a lot of compacted clay, mud, sand and other naturally occurring deposits. These sediments enable a picture of the changing nature of the floodplain to be produced. Every augur (which is around 7cm in diameter, up to 11m deep and producing samples at every 10cm under the ground) is therefore bagged, softened with water and then sieved using 2mm and 4mm screens to collect the different geological and human-made contents (as shown above). These contents add to the sedimentary data already recorded in the field to add further understanding to the geoarchaeological history of the floodplain. The sieving produces a range of stone clasts, which can include limestone, sandstone, granite etc., as well as other clasts, like rhizoconcretions and pottery sherds, which help to constrain the dates of the depositional events and the history of the floodplain. The auguring is taking place along a 3km traverse from the edge of the western desert to the banks of the river Nile at an approximate interval of every 200m, but this distance is reduced in complex sedimentary areas of the floodplain. The team average around 3 augurs per day.
ERT is used as a subsurface survey technique to complement the auguring information and provides import data to interpret the sediments between the auguring and as a check that no significant geomorphological features have been missed between the augur locations. You can see Dr Ginger Emery explaining how you collect and read the results of an ERT study to me above. 128 metal probes (placed 2m apart) are attached to what is effectively a car battery charger. Electrical currents are sent through the probes giving either high resistance or low resistance readings, depending on what deposits are actually present below ground.
You can read more about the team’s latest results from the 2015 season in JEA 101, coming out soon.
*I would like to thank Dr Angus Graham for his comments on this blog post.