Omo

A river basin in Ethiopia north of Lake Turkana, where fragmentary remains of Australopithecus and early Homo have been found. The same deposits have produced flakes of imported quartz, 2.4-2 million years, the oldest securely dated artifacts. The site is of outstanding importance as a basis for dating other sites throughout Africa, because its time-scale is unusually well fixed by palaeomagnetic studies, potassium argon dates, and faunal comparisons.

The Omo River basin is in Ethiopia north of Lake Turkana [formerly Lake Rudolf]. The 800-metre thick Shungura formation spanning the time from over 3 million to under 1 million years ago is of outstanding importance as a basis for dating other sites throughout Africa, because its time-scale is unusually well fixed by palaeo-magnetic studies and a series of potassium argon dates. Mammal remains suitable for correlation are found at all levels. In addition, hominids are numerous, though unfortunately much less complete than at sites like Koobi Fora. Stone tools (some possibly as old as 2.5 million years) are known from various levels. Two hominid skulls of late Pleistocene date are also known, but their status and exact date are unclear.