Iranica Antiqua, vol. XL, 2005 THE CHRONOLOGY AND ENVIRONMENTAL BACK- GROUND OF IRON AGE SETTLEMENT IN SOUTHEAST- ERN IRAN AND THE QUESTION OF THE ORIGIN OF THE QANAT IRRIGATION SYSTEM BY Peter MAGEE (Bryn Mawr College, USA) Introduction The Iranian Iron Age has been a focus of intense scholarly study for nearly a century. Excavations conducted in western, north-western and southern Iran have stimulated much debate concerning chronology, the effects of Assyrian and Urartian imperialism, and the impact of the Median and Achaemenid Empires. The focus on these areas of Iran derives largely from their connections with historically-attested imperial systems. South- eastern Iran, in contrast, has rarely been the focus of intense scholarly study. In this paper we wish to make some tentative suggestions concern- ing the chronology of Iron Age settlement in southeastern Iran based on new C14 data from the site of Tepe Yahya. In doing we will highlight the role of qanat technology and provide some regional data that suggests a different trajectory than has previously been argued for the origin and chronology of this irrigation system. Southeastern Iran and Tepe Yahya Southeastern Iran remains one of the least studied areas of Iron Age Iran. Early comments on the archaeology of this region can be found in Syke’s trek through the area in 1910 (Sykes, 1902, pp. 442–443), in which the Bronze Age site of Khinaman was noted. Stein’s typically extensive sur- veys noted Iron Age material from cairns at Fanuch and Damba Koh in Makran (Stein, 1937, pl. III) and a bronze socketed trilobate arrowhead that must be late Iron Age in date from the site of Bijnabad in the lower 218 P. MAGEE Halil Rud (Stein, 1937, pl. X). Boucharlat (1989) has presented a re-analy- sis of some of this material in which he was able to contextualise these cairns within those more recently noted in areas of Fars and southern Iran. Caldwell’s excavations at Tal-i Iblis in the Bard Sir Valley in 1964 and 1966 also revealed limited Iron Age occupation. A kiln in Area B was C14 dated to sometime in the second half of the second millennium BC or later (Caldwell and Sarraf, 1967, pp. 273–274) while some incised sherds and an iron dagger that were tentatively identified as Achaemenid in date were found on the surface (Caldwell and Sarraf, 1967, fig 1; Caldwell, 1967, fig. 29). In the 1970’s survey work by Williamson and Prickett revealed evidence for Iron Age occupation around Minab (Magee, 1995: Fig. 6.4) although it would seem that the bulk of this material dates to the Parthian and Sasanian periods (Priestman and Kennet, 2002; Kennet, 2003). The Iranian Center for Archaeological Research hoped to organize a six-year survey of this region beginning in the mid-1970’s. The results of the first two seasons of survey (1976 and 1977) were published (Sajjadi, 1987). Although two Iron Age sites are noted (sites 97 and 107), there is very lit- tle material published from site 97 and nothing published from site 107. Against this meagre collection of data stands the excavations conducted at Tepe Yahya by Harvard University under Professor C.C. Lamberg- Karlovsky between 1967 and 1975 (Fig. 1). A complete analysis of the Iron Age material is now in press (Magee, 2004) and preliminary publica- tions of the Iron Age platforms have been made (Lamberg-Karlovksy and Magee, 1997). We refer the reader to the forthcoming monograph for more detailed analysis of the Iron Age material from Tepe Yahya and note here the main stratigraphic sequence. The earliest Iron Age occupation is Period III which is marked by two stone and mudbrick, roughly square, buildings in the center of the mound. There is the possibility that a thick fortification wall surrounded these two buildings to form a citadel struc- ture. This re-occupation of the mound comes after an hiatus of uncertain length following the abandonment of the site after Period IVa. Period III is followed by a phase of occupation we have labelled ‘The Platform Period’. During this phase of occupation, two consecutive mudbrick plat- forms are constructed (Lamberg-Karlovksy and Magee, 1997). The func- tion of these is open to question but parallels can be made to the platform noted at Nad-i Ali in Seistan (Dales, 1977; Ghirshman, 1939). Such a comparison rests, however, on the Nad-i Ali chronology suggested by IRON AGE SETTLEMENT IN SOUTHEASTERN IRAN 219 Fig. 1. Map showing the location of Tepe Yahya. Dales (1977) and we should note that Besenval and Francfort (1994) have argued for a Bronze Age date for this monument on the basis of a ceramic jar found in the original excavations. Period II follows the Platform Period at Tepe Yahya. In this phase of occupation there are two sub-phases that were difficult to reconstruct from the excavation records. Nonetheless, it is clear that several mudbrick and stone constructed buildings were evident in this phase, some of which were clearly domestic in function; some con- taining storage vessels while others exhibiting evidence for industrial activities such as smelting. The Chronology of initial Iron Age settlement at Tepe Yahya In this paper, we are principally interested in the chronology of Period III at Tepe Yahya and how this may relate to broader processes of settlement 220 P. MAGEE in southeastern Iran. The chronology of Period III and the length of the hiatus between it and Period IVa have been commented upon in several early publications. In initial publications, Period III at the site was assigned a chronology beginning around c. 1000 BC. By 1986 (Beale, 1986), a re-analysis of the data suggested that this should be lowered to 700 BC while Period IVa ended around 1400 BC (Beale, 1986, p. 11). For the most part, this chronology was based on C14 dates that had very wide errors with resultant wide calibrated ranges. As part of the re-analysis of this material (Magee, 2004), 5 new charcoal samples were obtained from the organic material stored at the Peabody Museum at Harvard University. Two samples were obtained from Period III, each in a good context related to the two buildings that dominated this phase. Their C14 ages and cali- brated ranges are seen in Table 1. Sample Provenience 14c Age 2s Range Contribution to Probabilities WK 10145 Period III. A55 2568±63 840-410 BC 1.00 WK 10146 Period III. 2493±67 800-410 BC 1.00 Burnt Hall Table 1. C14 dates from Period III Tepe Yahya. The fact that the calibrated ranges of these two samples is much larger than their C14 errors reflects the nature of the calibration curve for this period. Between c. 750 and 400 BC the curve is relatively flat (Fig. 2). Samples that fall into this period will have, therefore, elongated calendric ranges. In any case, as with any C14 date it is the upper limit of the sam- ple that is most important. On the basis of these two dates and the obser- vation that Period III does not witness extensive rebuilding or multiple phases of occupation, one can state confidently that Period III at Tepe Yahya was in existence after c. 840 BC or to round to the nearest century, after 800 BC. This date is also borne out by a Bayesian analysis of these samples and those from the Platform Period (Magee, 2004, Table 6). Bayesian analysis (Buck et al., 1991) is a powerful tool that permits the incorporation of other data into a probabilistic analysis. The Tepe Yahya stratigraphic sequence and our confidence in the position of the C14 IRON AGE SETTLEMENT IN SOUTHEASTERN IRAN 221 Fig. 2. Calibration curve of the mid-first millennium BC. samples within that sequence, permitted us to re-analyse the calibrated ranges by incorporating stratigraphic information. This analysis suggests that Period III continued until c. 650 BC when the platforms were con- structed. The Tepe Yahya hiatus and settlement in adjoining regions If we accept an end date of Period IVA at Tepe Yahya of c. 1400 BC (Beale, 1986, p. 11), then a c. 600 year hiatus must be reckoned. When Tepe Yahya was excavated, there was little comparative data that facili- tated a contextualisation of this hiatus within broader settlement patterns in the Indo-Iranian borderlands and eastern Arabia. Since 1975, when the Tepe Yahya project ended, research has flourished in adjoining regions. Data from southeastern Arabia is particularly important in this regard. Extensive surveys and excavations have shown that few large settlements are known from c. 1600 BC until 1000 BC. Rather than assume that this is evidence of a depopulation of the region, researchers have turned their 222 P. MAGEE attention to explaining this process in terms of new lifeways, the effects of shifts in foreign trade patterns, and decreased visibility of settlement as a result of economic extensification (Magee and Carter, 1999). Similar phenomena have been argued by Franke-Vogt (2001) in her analysis of settlement patterns in the southern Indus Valley and Baluchistan. Envi- ronmental factors are one possible cause of this process (below) but the collapse of states in the Indus Valley around the middle of the second millennium BC and a decline in trade with Mesopotamia may also have had an impact. Whatever the cause of this decreased visibility in prehistoric settle- ment, data from southeastern Arabia suggests that, at least in that region, adaptation to increasing aridification led to archaeologically-vis- ible rapid settlement growth throughout this region towards the end of the second millennium BC (Magee, 1999, 2003).