Edward J. Keall’s research while affiliated with Royal Ontario Museum and other places

The results of the lead isotope analysis (LIA) of 15 copper-base artefacts from the Bronze Age site of al-Midamman, Yemen, are reported. The LIA data suggest the existence of an indigenous Bronze Age metal production and exchange system centred on the southern Red Sea region, distinct from those in neighbouring regions of Arabia and the Levant. These preliminary results are highly significant for the archaeology of the region, suggesting that local prehistoric copper extraction sites have thus far gone unrecorded, and highlighting the need for systematic archaeometallurgical fieldwork programmes in the countries surrounding the southern Red Sea.

In 1997, a hoard of copper-based objects was discovered at the megalithic site of al-Midamman, on the Red Sea Tihama coastal plain of the Republic of Yemen. Since there have been very few metal artifacts discovered in the lowlands of Yemen, and there was limited stratigraphy on the site, determining the time and place of production for these artifacts was difficult. A full investigation of the objects was deemed essential to determine their chronology and origin. Analysis included optical microscopy and scanning electron microscopy (SEM) for metallography, inductively coupled plasma spectrography (ICP) for bulk chemical composition, SEM to determine phase composition and corrosion products, and X-ray diffraction (XRD) to identify corrosion products.The objects can be divided into three types of copper and copper alloy: pure copper, arsenic rich copper, and tin rich copper. The difference in composition appears likely to be deliberate and suggests that the objects were produced sometime during the Early Bronze Age through the Middle Bronze Age. Further investigation of any metal objects discovered along the Yemeni coast and along the Ethiopian/ Eritrean side of the Red Sea is obviously essential.

In March 1997 the excavation team of Edward Keall, Head of the Department of Near Eastern and Asian Civilization of the Royal Ontario Museum, Toronto (Canada) found the remains of an apparently prehistoric site in a region that was supposed to have been uninhabited until the Middle Ages. On the site there are megalithic pillars of granite and basalt, weighing around 6 tons; some were part of what looks like a rectangular building. A cache of copper-based objects – consisting of two adzes, two daggers, four points, two razors and a leaf-shaped object – was found under one of the fallen megaliths. The authors present the as yet unpublished results of the chemical analysis carried out by ICP and the observations obtained by SEM/EDX and discuss briefly the significance of the data and the problems encountered while studying the items of the newly discovered civilization. The stylistic comparisons and the chemical composition of the objects suggest a date around the end of the 3rd or the beginning of the 2nd millennium BC, while other finds on the site seem to indicate a later period.