Smithsonian National Museum of Natural History

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Carboniferous

Kenya – East Turkana

(Plio-Pleistocene)


In East Africa, a large part of my field-based research (1969-81; 2002-03, 2009) has been focused on the northeast side of Lake Turkana – a region now known as East Turkana. When I started working there it was called East Rudolf. Lake Rudolf was named after the Crown Prince of Austria in 1888 by the explorer Hungarian Count Teleki, and renamed Turkana in 1975 after the dominant tribe in the region. Richard Leakey began his expedition there in 1968 and invited me to join as geologist for the 1969 field season. The main camp was established on a sandy peninsula near the lake called Koobi Fora, and this part of the large East Turkana region is commonly referred to as Koobi Fora.

Initially, my work at East Turkana was geological, but I developed an interest in how the abundant fossil vertebrates and their taphonomy related to different sedimentary environments – primarily ancient river channels, floodplains, deltas, and lake margins, and this became the topic of my Ph.D. Dissertation, which was finished in 1973 and published in 1975. During the years from 1969 and 1973, I also worked with Glynn Isaac and his students and Kenyan crew to document the environmental context and age relationships of East Turkana’s many archeological sites. After completing my thesis, I received Wenner-Gren Foundation support to study the depositional and taphonomic context of the many hominid sites; this work is published in Koobi Fora Monographs Volume 1. In 1974, with Catherine Badgley and Marc Monaghan, I focused on study of the modern depositional environments of East Turkana, digging many trenches to record their sedimentological records in order to improve interpretations of the ancient strata. I also worked with Diane Gifford-Gonzalez on a recently buried Dassanech campsite in 1974 and continued collaborating with Glynn Isaac’s archeological group through the late 1970’s.

In 1978-79, I ran a project with Léo Laporte (UC, Santa Cruz) and graduate students Andy Cohen and Hilde Schwartz that focused on a single time-slice in three different regions of East Turkana – the Ileret/Okote/Koobi Fora tuff interval, dated at about 1.5 Ma. Our goal was to document and compare the sedimentary environments, taphonomy, and paleontology of this 10-12m thick interval in the three areas. We initiated standardized surface sampling of the fossil vertebrates (“Bonewalks”) and combined this with more detailed information on the environmental context and associations of fossil animals using 10x10m squares, surface scraping, and excavation. We also dug many geological trenches to document the microstratigraphy, and one of these in Area 103 revealed hominid footprints amongst the tracks of hippos and other animals. This footprint level has recently been investigated further (GaJi10; See Bennett et al., 2009), but there are many other beds with animal footprints throughout the Koobi Fora tuff interval and adjacent strata. The paleontological excavations (PE’s, N=18) revealed much about the taphonomy and sedimentological history of bone accumulations in the different areas, as well as ecological differences in the contemporary faunas of the northern area of Ileret (floodplains, some lake margin) the Karari (inland river and floodplain), and Koobi Fora (fluvial-deltaic). At ~1.5 Ma, Ileret had more monkeys and more hominids preserved as fossils than Koobi Fora, where hippos, crocodiles and other semi-aquatic animals were common. Thus, paleogeographic and paleoenvironmental variation in the fauna is preserved in the fossil record, indicating a choice of habitats available to the hominins of the time (Homo erectus and Paranthopus boisei) over distances of kilometers to 10’s of km (Ileret is about 30 km from Koobi Fora).

In 2002-2003, Rene Bobe, Naomi Levin, Chris Campisano, and I worked on the earlier part of the record in the Koobi Fora Fm. to build a controlled sample of vertebrate fauna from the time period between 3.4 and 3.2 Ma, between the Tulu Bor and Allia Tuffs. The goal was to examine the paleoecology and paleoenvironments of the Tulu Bor Tuff Member, which can be correlated in time to the Sidi Hakoma Tuff in Ethiopia and thus provides a limited time slice when the faunas of two major rift basins can be compared. We also wanted to compare earlier faunal samples done with traditional paleontological survey methods with more controlled “bonewalks” where all bones were recorded. Among other findings, this showed that there are more fossil large animals such as hippos and elephants in the original bone assemblage than are represented in the collected and catalogued sample from earlier traditional paleontological surveys. This is not surprising (these fossils are large and heavy!) but it shows a bias in the ecological information one can reconstruct from catalogued records of traditionally collected fossil assemblages. Also, since identifiable specimens of the target groups for earlier collecting (mainly in the 1970’s) were removed from the field, these are somewhat under-represented in our sample, indicating that even 20+ years is not enough for continuing erosion to “renew” the surface fossil assemblage. Field surveys using standardized sampling methods, preferably in previously uncollected areas, are essential for accurate reconstructions of the ancient communities – a good reason to initiate new rounds of field work(!).

East Turkana: Current and Planned Research

In July, 2009, at the invitation of Jack Harris, I joined the Koobi Fora Field School for 10 days to see the new excavations of hominin and other animal footprints in Areas 103 (Koobi Fora) and 1A (Ileret) and also to link the previous 1978-79 work on the Okote Tuff level with the KFFS’s ongoing investigations. Refining interpretations of the paleogeography of this level as well as digitizing the 1970’s data on fauna, taphonomy, and sediments is a goal for the next several years, which will likely include additional field work. Data from controlled sampling of the surface fossils are being entered by volunteer Suzy McIntire, who also has been helping curate the collections of East Turkana fossils and sediments.

References Relating to East Turkana Research:

Behrensmeyer, A. K. 1970. Preliminary geological interpretation of a new hominid site in the Lake Rudolf Basin. Nature 226 (5242):225-226.

Vondra, C., G. Johnson, B. Bowen and A. Behrensmeyer. 1971. Preliminary

stratigraphical studies of the East Rudolf Basin, Kenya. Nature 23l (5300):245-248.

Isaac, G., R. Leakey and A. Behrensmeyer. 1971. Archeological traces of early hominid activities east of Lake Rudolf, Kenya. Science l73:ll29-ll34.

Behrensmeyer, A. K. 1974. Late Cenozoic sedimentation in the Lake Rudolf Basin, Kenya. Annals Geol. Surv. Egypt IV:287-306.

Behrensmeyer, A. K. 1975. The Taphonomy and Paleoecology of Plio-Pleistocene Vertebrate Assemblages East of Lake Rudolf, Kenya. Bull. MCZ l45 (l0):473-574. (Ph.D. Dissertation)

Behrensmeyer, A. K. 1976. Taphonomy and paleoecology in the hominid fossil record. In: Buettner-Janusch, J., (ed.), Yearbook of Anthropology, (Am. Assoc. Phys. Anthropologists), pp. 36-50.

Behrensmeyer, A. K. 1976. Fossil assemblages in relation to sedimentary environments in the East Rudolph succession. In: Coppens et al. (eds.), Stratigraphy, Paleoecology and Evolution in the Lake Rudolf Basin (Chicago: University of Chicago Press), pp. 383-40l.

Gifford, D. P. and A. K. Behrensmeyer. 1977. Observed formation and burial of a recent human occupation site in Kenya. Quat. Research 8: 245-266.

Behrensmeyer, A. K. 1978. The habitat of Plio-Pleistocene hominids in East Africa: taphonomic and microstratigraphic guidance. In: C. Jolly (ed.), Early Hominids of Africa (Duckworth: London), pp. l65-l89.

Behrensmeyer, A. K. 1978. Correlation in Plio-Pleistocene sequences of the northern Lake Turkana Basin: a summary of evidence and issues. In: W. W. Bishop (ed.), Geological Background to Fossil Man (Geol. Soc. London), pp. 42l-440.

Leakey, R. E., M. G. Leakey and A. K. Behrensmeyer. 1979. Ch. 5, The hominid catalogue. In: M. G. Leakey and R. E. Leakey (eds.), Koobi Fora Research Project, Vol. l, The fossil hominids and an introduction to their context l968-75, (Oxford: Clarendon Press), pp. 86-l82.

Laporte, L. F. and A. K. Behrensmeyer. 1980. Tracks and substrate reworking by terrestrial vertebrates in Quaternary sediments of Kenya. JSP, 50: l337-l346.

Bunn, H., Harris, J. W. K., Isaac, G., Kaufulu, Z., Kroll, E., Schick, K., Toth, N., Behrensmeyer, A. K. 1980. FxJ:50: an early Pleistocene site in northern Kenya. World Archeol. 12: 109-136.

Behrensmeyer, A. K. and L. F. Laporte. 1981. Footprints of a Pleistocene Hominid in Northern Kenya. Nature 289: l67-l69.

Behrensmeyer, A. K. and L. F. Laporte. 1982. Lateral facies analysis of Koobi Fora Formation, Northern Kenya: Summary of research objectives and goals. In: Paleoecology of Africa, vol. l4, eds. J. Coetzee and E. M. van Zinderen Bakker, pp. 147-150.

Behrensmeyer, A. K. 1982. The Geological Context of Human Evolution. Annual Reviews of Earth and Planetary Sciences l0: 39-60.

Behrensmeyer, A. K. 1985. Taphonomy and the paleoecologic reconstruction of hominid habitats in the Koobi Fora Formation. In: Coppens, Y., Ed., L'environment des hominides au Plio-Pleistocene. (Paris: Foundation Singer-Polignac). Pp. 309-324.

Behrensmeyer, A. K., Gordon, Kathleen D., and Yanagi, Glenn T., 1989. Non-human bone modification in Miocene fossils from Pakistan. In: Bone Modification (Proceedings of First International Conference on Bone Modification), eds. R. Bonnichsen and M. H. Sorg. Center for the Study of the First Americans, Orono, Maine, pp. 99-120.

Isaac, G. Ll. and Behrensmeyer, A. K. 1997. Chapter 2: Geological Context and Paleoenvironments. Pp. 12-53. In: Koobi Fora Research Project Volume 5: Plio-Pleistocene Archaeology. Glynn Ll. Isaac and B. Isaac, Eds. Oxford: Clarendon Press. 556 pp.

Behrensmeyer, A. K., N. E. Todd, R. Potts and G. E. McBrinn, 1997. Late Pliocene faunal turnover in the Turkana Basin, Kenya and Ethiopia. Science 278:1589-1594.

Bobe, R., A. K. Behrensmeyer, and R. E. Chapman. 2002. Faunal change, environmental variability and late Pliocene hominin evolution. Journal of Human Evolution 42:475-497. (Awarded First Prize, International Award for Excellence in Paleontological Research from the Paleontological Foundation of Teruel, Spain, and the Spanish Ministry of Science and Technology.)

Bobe, René and A. K. Behrensmeyer. 2004. The expansion of grassland ecosystems in Africa in relation to mammalial evolution and the origin of the genus Homo. Palaeogeography, Palaeoclimatology, Palaeoecology 207: 399-420.

Bobe Quinteros, R., A. K. Behrensmeyer and C. Ormazábal. 2004. Paleoclima u evolución faunística en el Plio-Pleistoceno de África y América del Sur. Ameghiniana (Rev. Asoc. Paleontol. Argent.) 41(4):641-649.

Bobe, R., Behrensmeyer, A.K., Chapman, R.E., Eck, G.G. 2004. Evolución humana en valle del Omo (Etiopía): relación con cambios faunísticos y variaciones ambientales en el Plioceno terminal. Fundamental 3, 1-59.

Bobe, René, Anna K. Behrensmeyer, Ralph E. Chapman, Gerald G. Eck, 2006. Faunal Change, Environmental Variability and Late Pliocene Hominin Evolution. Special publication of the Fundación Conjunto Paleontológico de Teruel, Spain. (Popular article)

Behrensmeyer, A. K. 2006. Climate change and human evolution. Science 311:476-478.

Bennett , Matthew R., John W.K. Harris, Brian G. Richmond, David R. Braun, Emma Mbua, Purity Kiura, Daniel Olago, Mzalendo Kibunjia, Christine Omuombo, Anna K. Behrensmeyer, David Huddart, Silvia Gonzalez. 2009. Early hominin foot morphology based on 1.5 million year-old footprints from Ileret, Kenya. Science 323, 1197-1201.

 

Turkana Database

 

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