PALEOENVIRONMENTAL RECONSTRUCTION OF LATE PLEISTOCENE TO HOLOCENE BEDS NEAR LOBOLO SPRINGS WEST TURKANA, KENYA

Geological field mapping, stratigraphy, and sedimentological analysis were conducted in a region of 30 km² north of the Turkwel river in West Turkana, Kenya with the purpose of reconstructing the paleoenvironment from the late Pleistocene through Holocene of a previously unexplored region. In 1982, a fossil cranium was discovered on the shores of Lobolo, originally thought to be from Eliye Springs, with morphology indicative of early Homo sapiens. With an earlier discovery of the same species in 1967 by Richard Leakey in northern Turkana and associated with tuff of the late Pleistocene, the interpretation of units near Lobolo will provide the environment of early anatomically modern humans of this region and external factors that may have affected their evolution. Although the cranium of Lobolo was uncovered 30 years ago, the geology of the region has yet to be explored in full detail. Preliminary observations of grain size and composition coincide with research from northern Turkana indicating lake high stand during the early Holocene, ~85 meters above present lake levels. It is also important to note lateral facies variations in west Turkana in addition to vertical changes due to fluctuating lake levels. Another site of exploration is a ~100 ft late Pleistocene cliff of lacustrine and estuarine deposits that were systematically sampled. Initial observations show very thin, silty iron oxide-rich beds alternating about every 40cm within brown to tan mudstone. The cycle of bands are likely due to productivity changes and may be associated with millennial-scale cycles.

Other preliminary observations include changes in coastline morphology due to faulting and/or slumping and paleo beach ridge 10 km or more inland. Future work will include examination of ostracods and dating rhizoliths due to the lack of tephra within this section of time.