Optically stimulated luminescence dating of the city wall system of ancient Tayma (NW Saudi Arabia) Nicole Klasen a, * , Max Engel a , Helmut Brückner a , Arnulf Hausleiter b , Andrea Intilia b , Ricardo Eichmann b , Mohammed H. al-Najem c , Said F. al-Said d a Institute for Geography, University of Cologne, Albertus-Magnus-Platz, D-50923 Köln, Germany b Orient Department, German Archaeological Institute (DAI), Podbielskiallee 69-71, D-14195 Berlin, Germany c Tayma Museum of Archaeology and Ethnography, P.O. Box 22, 71914 Tayma, Kingdom of Saudi Arabia d College of Tourism and Archaeology, King Saud University, P.O. Box 2456,11451 Riyadh, Saudi Arabia article info Article history: Received 27 August 2010 Received in revised form 14 March 2011 Accepted 17 March 2011 Keywords: OSL dating Geoarchaeology City wall Tayma Saudi Arabia abstract In addition to a series of chronological markers (artefacts, pottery) in the archaeological contexts of ancient Tayma (NW Saudi Arabia), optically stimulated luminescence (OSL) and radiocarbon dating techniques were applied to generate reliable ages for the city wall system of the oasis. A massive aeolian sand deposit burying the oldest part of the outer wall of Tayma was sampled to obtain a minimum age for the construction of this wall. The sequence of OSL ages from the inactive dune (ID) (4900  300 a, 5100  400 a, 4400  300 a, 3900  200 a, 4000  200 a) is in full accordance with 14 C-AMS ages of charcoal embedded into the same dune (4190e4420 cal BP, 3870e4080 cal BP). Underlying alluvial samples from the inactive gravel sheet (IGS) in contrast give maximum ages for the construction which scatter between 6600  300 a and 4900  400 a. The new dating sequence provides evidence that the oldest part of the ancient city wall system already existed in the 2nd half of the 3rd mill. BC which is earlier than expected thus far from archaeological and architectural interpretation. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction The oasis of Tayma (NW Saudi Arabia) (Fig. 1) has a rich cultural heritage consisting of a large number of historic buildings and artefacts beginning with the late Neolithic. Throughout antiquity, the site owed its importance to the extensive perennial ground- water resources (Eichmann et al., 2006a). A highly sophisticated system of hydrotechnical installations, probably more than 3000 years old, provided access to water and an efficient use of resources (Hamann et al., 2008). Archaeological exploration of Tayma started in 1876e78 when Charles M. Doughty discovered and copied several Nabatean inscriptions during his stay (Doughty, 1888), followed by visits of Charles Huber and Jules Euting in 1880 and 1884 (Euting,1896/1914). Later, systematic surveys and excavations at Tayma were carried out by Philby (1957), Parr et al. (1970), Winnett and Reed (1970), Bawden et al. (1980), Livingstone et al. (1983) and several Saudi archaeolo- gists (e.g., Abu Duruk, 1986; Al-Hajri, 2006; Al-Taim a’i, 2006); for detailed information on the history of the archaeological research at Tayma see Eichmann et al. (2006b, pp. 94e95). In 2004 the Orient Department of the German Archaeological Institute Berlin (DAI) and the General Commission for Tourism and Antiquities, Kingdom of Saudi Arabia, began a long-term joint project aimed at investigating the culture and the environment of the Tayma oasis and its role within the regional cultural and historical background. Research activities cover the main ancient settlement mound of Qraya (Fig. 1) as well as the extended city wall system, peripheral burial sites, parts of the ancient water supply system which are distributed over the entire oasis, and also the adjacent sabkha landform, filled by a lake during the early Holocene (Eichmann et al., 2006a, 2006b; Hamann et al., 2008; Hausleiter, 2010; Schneider, 2010; Wellbrock and Grottker, 2010; Engel et al., in press). Recent investigations extended the chronology of the oasis considerably. Earliest evidence of human activity is represented by Neolithic or post-Neolithic single and multiple flint drills which are attributed to cattle-breeding nomads populating the area during this time. Thus far, data collected from archaeological excavations indicate that the site was settled at least from the Middle Bronze Age (1st half of the 2nd millennium BC) to modern times (Eichmann et al., 2006a). More detailed evidence exists from the Early Iron Age (12th to 9th centuries BC) onwards, when Tayma obtained significant importance as a caravan station at a branch of * Corresponding author. Tel.: þ49 1520 8687029. E-mail address: nicole.klasen@uni-koeln.de (N. Klasen). Contents lists available at ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas 0305-4403/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.jas.2011.03.018 Journal of Archaeological Science 38 (2011) 1818e1826