KOOBI FORA
(includes East Turkana, Ileret)
LOCATION
Collecting area to the east of Lake Turkana, northern
Kenya. The name Koobi Fora originally applied to a
specific lakeside locality, but has now come to refer to
the entire area of exposures, formerly known as “East
Rudolf” or “East Turkana,” that extends inland along
the eastern shore of Lake Turkana, from Ileret in the
N to Allia Bay in the S.
DISCOVERY
The fossiliferous potential of this area was first identi-
fied by R. Leakey in 1967. From the first organized
expedition in 1968, until the early 1980s, thousands of
mammalian fossils, including many hominids, were
recovered by collectors under the direction of R.
Leakey and G. Isaac.
MATERIAL
Between 1968 and 1982, more than 170 hominid fos-
sils were recovered. These ranged from isolated teeth
to entire crania and a partial skeleton. A complete list-
ing is given by Day (1986), and cranial specimens
have been comprehensively monographed by Wood
(1991). Material recovered included both robust aus-
tralopiths and specimens attributed to Homo; all are
referred to by their Kenya National Museums (KNM-
ER) catalog numbers. Well-known examples of the
latter include the crania KNM-ER 1470, 1813, 3733,
and 3883, and the mandible KNM-ER 1992.
DATING AND STRATIGRAPHIC CONTEXT
The Koobi Fora fossils are mostly surface finds in a
series of lacustrine and fluvial deposits, which are in-
terspersed with numerous volcanic tuffs that have
provided the markers for stratigraphic reconstruction.
A complex history of local faulting exacerbates prob-
lems of correlating individual tuff exposures; and, to-
gether with some problematic radiometric dates, plus
an initial failure to record exact locality information
(specimens were at first referred simply to numbered
collecting areas), this led to some dispute over the ex-
act antiquity of some important hominid specimens
including ER 1470 (see accounts in Lewin, 1987;
Tattersall, 1995). The introduction of techniques for
identifying the tuffs from specific eruptions by their
“geochemical fingerprints” (e.g., Cerling and Brown,
1982) permitted resolution of many of these problems
by F. Brown, C. Feibel and their co-workers, whose
studies (e.g., Brown et al., 1985; Brown and Feibel,
1986; Feibel et al., 1989) have greatly clarified the
stratigraphic sequence. These same authors have also
re-identified the hominid find sites and fixed their
positions within the revised stratigraphy by relating
them to identified marker beds.
All of the Koobi Fora deposits of interest here are
now assigned to the Koobi Fora Fm (which includes
the Kubi Algi and Guomde Fms recognized earlier).
Within a total sediment thickness of almost
600 m, eight members are recognized, each identified
by designated tuffs. Three stratigraphically contiguous
members, namely, the Burgi, KBS, and Okote, which132