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Naivasha Virtual Fieldcourse

Pre-history

Palaeontologists agree that some 16 million years ago, the unique geological features of the Rift Valley created ideal conditions for the development and then the preservation of a particularly rich fossil record, including bony remains of ancient hominids and of the fauna that had populated the prehistoric Rift Valley grasslands. Calcium carbonate-rich ashes, repeatedly thrown out in plentiful amount by the volcanoes surrounding the Rift Valley floor, contributed to preserve ancient history by turning their bones into fossils.

The portion of the Rift that is in today's northern Kenya became particularly important for modern palaeontology, thanks to the discoveries made in the 1960s and 1970s by a white Kenyan family, Louis and Mary Leakey and their son Richard. The most astounding discovery was a skull attributed to an Australopithecine precursor of modern Homo sapiens, found by Richard Leakey at Koobi Fora, north-east of Lake Turkana, has been called Homo rudolfensiswith the National Museum accession number (KNM ER 1470).

Despite being part of the Rift Valley's ancient history, the Lake Naivasha Basin is unlikely to contain remains of the distant past due to the great transformations that have taken place in the recent history of its landscape. Deep sediment cores taken from the mid basin of Lake Naivasha, as well as analysis of rock strata accumulated on the Rift Valley slopes, confirm that on more of one occasion a water level rise occurred in the basin leading sometimes to the coverage of most of its lowlands, up to a point where lakes Naivasha, Elementeita and Nakuru where united in a single large water body. Any fossil remains that could have been found in the basin are therefore likely to have been buried deep in lake sediments and in soils that derived from the dessication of this original large lake. The last time that such a situation occurred was some 30,000 years ago, when the massive lake outpoured towards the southern edge of the basin, through what is now known as the Hell's Gate gorge.