Application of combined geophysical and archaeological survey techniques: a case study of Singida Region, Tanzania

Abstract

The seismically active Singida region in central Tanzania lies at the edge of the East African Rift System (EARS) which is locally designated the Gregory Rift. The archaeological record of the region, especially in the eastern part of the Ikungi District, unlike that of northern Tanzania, is comparatively unknown, despite early archaeological expeditions hinting at its potential. Recent research in the eastern area suggests that it preserves a long record of hominin occupation spanning the Early to Late Stone Age. This interdisciplinary field work, carried out between August 2022 to August 2023, resulted in the discovery of a relatively deep package of Quaternary deposits, revealing assemblages of artifacts dating from Early Stone Age (ESA) to Middle Stone Age (MSA) periods. This testifies, for the first time, to a long term and more scattered human occupation in this part of this central region close to the famed Oldupai Gorge, since other sites were found across the Gregory scarp and the nearby Singida-Arusha highway. We also utilized magnetic surveys acquired with a Cesium vapor magnetometer coupled with magnetic susceptibility measurements using a SM-30 device in the sites, which revealed ancient fireplaces potteries, furnaces, Iron ore and other metallic materials of various ages, hence proving the success of multiple applications of rock magnetism combined with archaeological approaches in the region. We provide evidence of pedological and archaeological records of the end of the African Humid Period (AHP) in this eastern part of the region and possibly other later abrupt arid events which exhibit synchronicity with similar events recorded in sediment archives from Lake Victoria or further South (i.e., Lake Nyasa). This promising venue of investigation bears much potential and calls for further study. Finally, we question the potential drivers that could possibly explain human settlements or migration pathways in conjunction with the shift from hunting-gathering to pastoralism.

Keywords: Magnetic mapping; Low-field magnetic susceptibility; Archaeological sites; Heritage resources; Natural resources