GEOARCHAEOLOGICAL EVIDENCE OF MID- TO LATE-HOLOCENE ENVIRONMENTS AT SAI ISLAND, SUDAN

Geoarchaeological investigations at Sai Island (Site 8-B-76), in northern Sudan, provide sedimentologic and carbonate isotope data that allow for environmental reconstruction of a landscape that was home to both mid-Holocene hunter-gatherers and later-Holocene pastoralist groups. Paleosol carbonates reveal isotopic values consistent with mid-Holocene pluvial phase deposition, and geoarchaeological trenches provide evidence of active channel migration. These pieces of evidence suggest a frequently shifting floodplain environment with significant local meteoric inputs and possible flooding. A sequence of very localized buried surfaces indicate well-developed soils and associated pedogenic carbonate nodules, representing potential localized stable occupation sites for Khartoum Variant foragers and Abkan pastoralists active at Sai during the most recent humid phase ca. 9000-4500 BP. Isotopic evidence supports a mix of C3/C4 vegetation and possible local evaporative enrichment during carbonate formation. Later aridification of North Africa coincided with a shift to full range nomadic pastoralism within aeolian sediments, suggesting more limited wild vegetation and lower surface water availability.