The archaeology of Megaliths culture in the Lake Eyasi Basin, Northern Tanzania

Abstract

The study investigated the archaeology of the megaliths’ culture in the Lake Eyasi Basin, the northern part of Tanzania, an area previously noted for megalithic structures whose historical significance and origins were not well-documented. Earlier researchers suggested these sites might be related to the Engaruka cultural complex, but chronological inconsistencies remained. This study used a mixed-methods approach, incorporating both quantitative and qualitative data. Primary data were obtained through archaeological surveys, excavations, archival research, and paleoenvironmental data collection. Secondary data were gathered by reviewing existing literature, including books, research papers, and reports, focused on megaliths and other archaeological topics relevant to the Lake Eyasi Basin. The findings highlight the advanced engineering, craftsmanship, and potential spiritual significance behind the megalithic structures. Various forms, such as dolmens, burial cairns, stone enclosures and stone circles, reflect the societies' complex cultural, social, and possibly religious dimensions. The studied sites (Olpiro, Oldogom, and Barjomajega) exhibited distinctive pottery, microlithic tools, polished axes, grinding stones, and metalworking materials, indicating specialised tool use and metallurgical knowledge. Animal remains indicated reliance on livestock, while decorative beads suggested symbolic cultural practices. Radiocarbon dating places these sites in the Pastoral Neolithic and Late Iron Age, from 2500 years BP to the 14th century AD. The absence of Early Iron Age (EIA) pottery indicates abandonment during this period, with a gap between 300 and 700 AD before resettlement in the Late Iron Age (LIA) time. In addition, the phytolith data suggest that environmental conditions 2,500 years ago were similar to today’s semi-arid environment, implying that cultural developments were likely driven by factors other than environmental shifts. The study proposes further research, including refined radiocarbon dating to resolve chronological gaps, advanced LiDAR and GIS mapping to locate undiscovered sites, and microscopic analysis of artefacts to reveal material, technological, and trade details. Additionally, it recommends investigating links between contemporary pastoralist practices and ancient megalithic traditions. Finally, expanding phytolith and pollen analysis could further clarify the relationship between stable environmental conditions and cultural continuity.