Geochronology of the Turkana Depression of Northern Kenya and Southern Ethiopia

The Turkana Depression, spanning northern Kenya and southern Ethiopia, reveals a detailed geochronological record of sedimentary and volcanic rocks from the Mesozoic to the Holocene. Key findings include the identification of Cretaceous strata in Lokitaung Gorge and early Eocene volcanism (34–36 Ma) in the region, marking the onset of significant volcanic activity. Oligocene to Miocene sequences (23–9.1 Ma) provide critical age constraints for fossiliferous sedimentary deposits, while Pliocene strata of the Omo Group (4.3 Ma to present) offer a continuous record with notable gaps. The study leverages (40)Ar/(39)Ar dating on volcanic ash layers and K/Ar ages on basalts, supplemented by paleomagnetic polarity stratigraphy, to establish precise age control from 4.2 to 0.75 Ma. Additionally, the Kibish Formation in the lower Omo Valley records deposition between 0.2 and 0.1 Ma, with Member IV (correlative to the Galana Boi Formation) dated to 12–7 ka BP.

Brown, F. H., & Mcdougall, I. (2011). Geochronology of the Turkana Depression of Northern Kenya and Southern Ethiopia. Evolutionary Anthropology: Issues, News, and Reviews, 20(6), 217–227. Portico. https://doi.org/10.1002/evan.20318