New results to discuss possibility of irrigation in Bat (Wadi Sharsah, northwestern Oman) before Hafit period (ca. 3100-2700 BCE)

International audience ; Registered as a World Heritage Site by UNESCO in 1989, the extensive archaeological site of Bat is situatedwithin the Wadi Sharsah and around the modern village and palm grove of Bat, 24 km from the modern city ofIbri in northwestern Oman. The archaeological remains from the Bronze Age excavated by the Bat ArchaeologicalProject are located in two mains areas. The northern area consists of a chain of low limestone hills cut by waditributaries leading to the main Wadi Sharsah. It is characterised by an exceptionnally high density of graves fromtwo successive Bronze Age periods : Hafit (ca. 3100-2700 BCE) and Umm an-Nar (ca. 2700-2000 BCE). Southof the Bat cemetery, in the flat part of the valley, there are several large circular structures (known historically as« towers ») and remains from both Hafit and Umm an-Nar periods, as well as later periods. Geomorphologicalmapping of the floodplain, associated with archaeological survey, have identified walls suggesting that during theUmm an-Nar period there was a system of irrigation which controlled flood water. Sedimentological, malacological,C14 dating and micromorphological studies of a 10 m long and 2.5 m high section located 143 m northeast ofthe Tower 1146 on the left bank of a small tributary of the Wadi Sharsah provide strong argument for the presenceof an irrigation system that began before the Hafit period. New C14 datings confirm this hypothesis. Botanicalmacro-remains collected during the excavation of early Bronze Age structures at Bat further indicate the presenceof date palm gardens since the 3rd millenium BCE allowing the cultivation of several crop species, in particularcereals. Most generally the global palaeoenvironmental reconstruction from our data supports a model of a generaltrend of aridification from Bronze Age to iron Age.