Koobi Fora
Koobi Fora is a region around Koobi Fora Ridge, on the eastern shore of Lake Turkana, Kenya. It is in the territory of the nomadic Gabbra people.[1] The term East Turkana can be used for the whole area.[2]
The ridge is an outcrop of mainly Pliocene/Pleistocene sediments. It is composed of claystones, siltstones, and sandstones that preserve numerous fossils of land mammals, including early hominin species. The ridge is being eroded into a badlands terrain by a series of ephemeral rivers that drain into the northeast portion of modern Lake Turkana.
In 1968 Richard Leakey established the Koobi Fora Base Camp on a large sandspit projecting into the lake near the ridge, which he called the Koobi Fora Spit. A survey and numerous excavations showed the region was a source of hominin fossils from the last 4.2 million years. Far exceeding the number of humanoid fossils are the non-humanoid fossils, which give us a look at the fauna and flora as far back as the Miocene.
In 1973, the government of Kenya reserved the region as Sibiloi National Park, establishing a headquarters for the National Museums of Kenya on Koobi Fora Spit. The reserve is well-maintained and is well-guarded by friendly but armed park police. Protection of sites and especially of wildlife are of prime concern.
Exploration and excavation are done by the Koobi Fora Research Project (KFRP), which collaborates with universities and individuals around the world.[3]
Archaeological sites and artifacts
[change | change source]
Archaeological sites
[change | change source]The simple hierarchy of scientific places for Koobi Fora is the following: Koobi Fora is the region; the region is divided into fossil collecting areas; within fossil collection areas there are archaeological sites and hominid paleontological localities.
Locating and referencing the hundreds of sites in the Koobi Fora region has been an ongoing process. The entire reservation was divided into somewhat over 100 numbered areas.[4] In the year 2000 the KFRP went over to a GPS system.[5]
Some notable areas are as follows.
- Area 105
The first archaeological site, i.e., FxJj 1, was found in Area 105. It is nicknamed the KBS site for Kay Behrensmeyer Site, after the researcher who first found stone tools there. This site is also the place where the first tuff was found, i.e., the KBS Tuff.
- Area 131
It is known as the location of skull 1470, discovered by Bernard Ngeneo in 1972, reconstructed by Meave Leakey, later reconstructed and named Homo habilis by Richard Leakey, as possibly the first of the genus Homo, and finally Homo rudolfensis. Richard Leakey found it 45 m below the 1.89 my KBS tuff; thus, it is older than that date, but is conventionally dated to it.[6]
Hominid fossils
[change | change source]Searching for and finding fossils in such a large area is another difficult problem. One solution has been to organize all persons present into a group to sweep a designated area. Richard Leakey devised a method that produced better results: he organized and trained a search team of Kenyans, which became known as "the hominid gang", under the leadership of Kamoya Kimeu. They have discovered the majority of the fossil Hominins, which currently amount to over 200.
Koobi Fora is perhaps best known for its specimens of the genus Homo, but those of the genus Australopithecus also have been found. The following species are represented:[7]
| Species Name | Dates (KF only) |
Representative Fossils | Notes |
|---|---|---|---|
| Australopithecus anamensis | 4.2-3.9 mya | 30731, -44, -45, -50, 35228, -31, -32, -33, -35, -36, -38 | Found at Allia Bay.[8] Earliest evidence of bipedal gait.[9] |
| Australopithecus boisei | 2.1-1.1 mya. | 406, 729, 13750, 23000, 732. | |
| Homo habilis | 1.9-1.6 mya | 1813, 1501, 1502, 1805, 1808.[10] | Called "habilines" or "hablines". Others have been reclassified from this species to Homo rudolfensis. Habilis is considered the earliest or among the earliest of Homo. |
| Homo rudolfensis | 1.9-1.6 mya[11] | 1470, 1912, 1590, 3732, 1801, 1802, 1472. | Rudolfensis may split again to place some fossils, such as 1470, with Kenyanthropus platyops. Rudolfensis also shares the name "habline." |
| Homo ergaster | 1.8-1.4 mya | 992, 730, 731, 819, 820, 3733, 3883. | Considered a sort of pre-erectus if not early Homo erectus, from which it was split. Some refer to ergaster as the African erectus.[12] |
Australopithecus and Homo seem to have coexisted in the region for about one million years. One possible explanation is different food sources.[13] It is believed that Australopithecus became extinct and Homo went on to generate later species.
Stone tools
[change | change source]Large quantities of stone tools have been found at Koobi Fora both on the surface and in caches, which have dates of their own, but are seldom in association with hominins. No other candidates for their manufacture have been found, however. The tools are Oldowan and Acheulean. The Koobi Fora community has devised the following teminology[14] to describe three local industries:
| Industry Name | Dates | Representative Sites | Notes |
|---|---|---|---|
| KBS Oldowan | 1.89-1.65 mya (KBS Member) | FxJj1, FxJj3, FxJj10. | Comparable to Bed I Oldowan at Olduvai. Low ratio of flake scrapers to choppers. |
| Karari, named after the Karari/Abergaya Ridge. | 1.65-1.39 mya (Okote Member) | FxJj16, FxJj18GL, FxJj20M | Comparable to Bed II Oldowan at Olduvai. High ratio of scrapers to choppers. |
| Early Acheulean |
With the change from Olduwan to Acheulean technique, hominins got more of a return for a given output of energy and could do more. The chief technological development was the edge of the handax.[15] The advantage of the "core reduction strategy" was more and thinner flakes per mass of cores. More and better flakes meant better use of carcasses and therefore a need for fewer carcasses, less hunting, etc. Moreover, the increased number of flakes available made ranging farther from the source of the stone possible and gave more staying power to the hunt.
Stratigraphy
[change | change source]Koobi Fora is underlain by Pliocene basalts and filled with nearly 600 meters of Pliocene-Pleistocene sediments, dating from about four-million to one-million years ago.[16]
Most early human fossils and archaeological remains come from the upper portion of the Burgi Member, the KBS Member, and the Okote Member. The members reflect changing environments in the Turkana Basin, from lake and delta ones during Burgi Member times to rivers and floodplains in Okote Member times.
The stratigraphy of the Koobi Fora Formation is one of the best studied and calibrated in East Africa.[17] Controversial dating of the KBS Tuff during the 1970s helped to spearhead the development of modern potassium/argon and argon/argon geological dating methods. In addition, the unique fusion between geochronology and mammal evolutionary studies has made the Koobi Fora Formation a standard for all of Pliocene-Pleistocene Africa.
References
[change | change source]- ↑ Koobi Fora: Historical Background, National Museums of Kenya, archived from the original on 20 July 2011, retrieved 30 April 2010
- ↑ A nice map Archived 2006-08-29 at the Wayback Machine can be found at the Wesleyan site.
- ↑ For more information, refer to the KFRP Journal site currently being maintained by Louise Leakey. One notable collaboration is the Koobi Fora Field School Archived 2007-03-28 at the Wayback Machine conducted yearly by Rutgers University, which combines education and research.
- ↑ The papers of Glynn Isaacs Archived 2007-01-19 at the Wayback Machine show his extensive reliance on this system, which is still in use today.
- ↑ Jablonski, Nina (2004), "Putting Technology to Work at Koobi Fora (Special report)", KFRP Field Season Dispatches: Special report, Koobi Fora Research Project, archived from the original on 16 May 2011, retrieved 30 April 2010
- ↑ Establishing the date and the species has been a long and often painful process. Accordingly Leakey and Lewin (People of the Lake, Chapter 2) refer to 1470 as "... the famous - some say infamous - skull ...."
- ↑ Much of the literature on the subject since 1991 refers to some pseudo-taxa created by Wood: Homo sp. indet. is "Homo, species indeterminate"; Homo gen. et spec. indet. is "Homo, genus and species indeterminate"; Homo aff. H. erectus is "Homo with affinities to Homo erectus"; H. erectus sensu stricto is "Homo erectus in the strict sense." The subject has moved on since Wood; for example, "Hominids" are now "Hominins." For a review of the book in some detail, see the Book Reviews Archived 2006-06-24 at the Wayback Machine section of the American Journal of Physical Anthropology S9:499-504 (1992).
- ↑ Map at Allia Bay Archived 2006-08-29 at the Wayback Machine.
- ↑ See New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya, Meave Leakey et al. in Nature, 376, 565 - 571 (17 August 2002). Summary and bibliography at no cost.
- ↑ A list of fossils, discoverers, descriptions, drawings or photographs, and KNM numbers, along with some dates, can be found at Steven Heslip's page on the Michigan State University website. A good description of habilis with photographs can be found at Bruce MacEvoy's 'Handprint' website and another of numbered habilis and other fossils at Smithsonian National Museum website.
- ↑ As 1470 was below the KBS tuff, some have pushed the date back to 2.3, 2.4 or even 2.5 my.
- ↑ Homo ergaster is Wood's "Homo aff. H. erectus."
- ↑ People of the Lake Chapter 5.
- ↑ The tools and classifications are well described in a number of pages at KOOBI FORA ARCHAEOLOGY Archived 2003-03-21 at the Wayback Machine, which is being maintained at the Maricopa Community Colleges site.
- ↑ Technological Developments in the Oldowan of Koobi Fora: innovative techniques of artifact analysis, David R. Braun, Jack W.K. Harris, in TREBALLS D’ARQUEOLOGIA, 9, Centre d’Estudis del Patrimoni Arqueològic de la Prehistòria, Autonomous University of Barcelona.
- ↑ The system is as follows. One "member" is all the layers between two tuffs, or layers of volcanic ash. The member is named from the bottom tuff, considered to begin it. The tuffs are dated. Obviously, a fossil or artifact is dated by the member in which it was found. A complete presentation of the members and their names with dates and a diagram can be found at STRATIGRAPHY OF KOOBI FORA Archived 2003-06-28 at the Wayback Machine and therefore that information is not repeated here.
- ↑ Feibel, Craig S; Brown, Francis H; McDougall, Ian (1989), "Stratigraphic Context of Fossil Hominids from the Omo Group deposits: Northern Turkana Basin, Kenya and Ethiopia", American Journal of Physical Anthropology, 78 (4): 595–622, doi:10.1002/ajpa.1330780412, PMID 2712166, archived from the original on 2013-01-05, retrieved 2013-01-09