AN 8000-YEAR RECORD OF FLUVIAL ACTIVITY AND HUMAN SETTLEMENT IN THE DESERT NILE OF NORTHERN SUDAN

The relationship between climate change and the development of the great riverine civilizations of the Old World is poorly understood because of inadequate dating control and the limited integration of archaeological, fluvial and climate records. This paper presents the most comprehensive and robustly-dated archaeological and fluvial geomorphological datasets ever compiled for the desert Nile. Our work has focused on the valley floor hinterland of the Kingdom of Kerma (2400 –1450 BC) in Northern Sudan. Kerma emerged as a rival to Egypt during Africa’s first ‘Dark Age’ drought. Unlike other irrigation-based agriculturists in Egypt, Mesopotamia and the Indus Valley however, Kerma flourished during the environmental crisis of 2200 BC. We have studied the Holocene stratigraphy of palaeochannel systems across an 80 km reach of the desert Nile upstream of Kerma in the Northern Dongola Reach. Our recent work in Northern Sudan has shown that the sedimentary records in abandoned Nile channels are important archives of Holocene flood history. Channel fills comprise stacked records of fine-grained flood sediments with fluvially-reworked aeolian sands. The latter have been dated using OSL and the former can be sourced using strontium isotopes. Using OSL we have precisely dated – over an eight thousand year period – when channels flowed and when they dried up and have integrated these geological data with an independently-dated archaeological record. This approach allows some of the more contentious ideas on the relationship between climate, river system change, and civilization ‘collapse’ in the Old World to be rigorously tested including the impact of the 4.2 ka and other rapid climate change events. Our results show that constructing a highly resolved fluvial sedimentary archive in the floodplain where irrigation-based agriculture was practised is essential before potential causal links between climate change and major disruptions of ancient alluvial civilizations can be fully explored.