In Africa, most of the field team 2012

The project’s work in West Turkana aims at investigating the biological and cultural evidence for the evolution of Homo sapiens in the area. The three field seasons carried out during the Late Quaternary Human Evolution in West Turkana Project (LQWT09, LQWT10, LQWT11) identified and explored a number of rich palaeontological and archaeological localities in a small area southwest of Lake Turkana, along the western margins of the Natome River (a tributary of the Kerio). In 2012, the In Africa project expanded the survey and excavations in this area by targeting one of the living late Pleistocene/early Holocene sites (KL4), the extensive Middle Stone Age locality of KL3, and extending the geological stratigraphic study at Natome and KL3. The discovery of the new site of Nataruk early in the season added the excavation of this fantastic burial site to the activities.

The first field season of the In Africa Project in West Turkana initiated larger scale excavations of some of the archaeological localities recorded and mapped during the LQWT Project. The work carried out as part of the LQWT Project between 2009 and 2011 provided the baseline understanding of the chronology of the main geo-morphological features of the area being studied, the general nature of the material exposed, as well as the location of specifically human occupation/use sites.

Distribution of main palaeontological and archaeological localities surveyed between 2009 and 2012, including the site of Nataruk, discovered in 2012

These localities were named after the local Turkana name for each small area, and numbered sequentially to identify sub-localities of prehistoric interest. Most of these localities are of late Pleistocene/early Holocene age, and contain the fossil remains of the animal community and people that lived and used the shores of a much larger lake PalaeoTurkana at the time. These late Pleistocene/early Holocene localities are:

  1. Natome 1, 2
  2. Kalakoel 1, 2, 7
  3. Locher Akwan 1, 2
  4. Nakwapo 1, 2

Archaeological remains are comparatively sparse, and represent the discarded tools of these late Quaternary populations. Contrastingly, two very rich archaeological sites, located 3 to 5 km South/Southwest of the palaeolake shore, contain substantial evidence of intense use, possible occupation, and human burials. These sites were named Kalakoel 4 and 6. Only KL4 has been studied so far. KL6 is within metres of a large Turkana homestead and to the effects of erosion and deflation, trampling by humans, goats and camels has further the site.

An earlier occupation is also evidenced in this part of the Turkana Basin by the presence of Middle Stone Age (MSA) lithic assemblages. Preliminary dates on fauna from one of these sites confirm a late Middle Pleistocene age of at least some of the MSA in the area. MSA occurrences were identified at three localities:

  1. Locher Akwan 1
  2. Kalakoel 7
  3. Kalakoel 3

In order to confirm some of the main aspects of the findings, as well as to initiate the systematic study of the Middle Stone Age localities, the specific objectives of the 2012 field season were to:

  1. Excavate a series of geological trenches to expose stratigraphic profiles at the localities of Natome 1, Kalakoel 4, and Kalakoel 3, to be described by Prof Hema Achyuthan, from Anna University in Chennai (a specialist in late Quaternary desert lake deposits)
  2. To carry out a small archaeological excavation at the site of Kalakoel 4 (KL4) to compare the lake shore localities to a human occupation site in the area
  3. To carry out the spatial survey of the northern part of  Natome 1 and Natome 2
  4. To begin the systematic survey of the Middle Stone Age site of Kalakoel 3

Early in the season, a new site named here Nataruk was discovered to the west of KL4. The site had a number of completely or partially exposed human skeletons in varying degrees of preservation. A systematic excavation of some of the skeletal remains at the site was carried out. As was the case for the research carried out as part of the LQWT Project (2009-2011), logistic and scientific support was integrated with the research programmes and protocols of the NMK and the Turkana Basin Institute. Mr Justus Edung (NMK, Lodwar) is the National Museum’s Field Research Support Officer for the project’s fieldwork in the Turkana Basin.

Archaeological Excavation of Kalakoel 4

Human skeleton excavated at KL4 in August 2012

The site of KL4 was first discovered in 2009, when a brief survey of its western end identified a very fragmentary exposed human skeleton. KL4 is a ridge that runs for approximately 2 km east-west c. 2 m above an extensive flat plain to the north. In 2011, a survey of the area to the east from where the fragmentary skeleton was recorded in 2009 revealed an extensive site, characterised by large numbers of surface-exposed fragments of hippopotami (specially large numbers of broken teeth), stone tools (mainly microliths) and pottery. The site also contains a number of burials, most of which were exposed by erosion and are on the surface being further fragmented by trampling by the numerous herds of goats. Three of the partially exposed skeletons were excavated in 2011, although these were in a very poor state of preservation, and a number of the human bone surface scatters collected. The aim of this year’s work at the site was to excavate in detail a small area within the densest part of the site, to excavate geological trenches that would allow us to establish the stratigraphic relation between the ridge and the lower-lying plain to the north, and to establish the extent of archaeological debris and quantify its density spatially. The work on KL4 was mainly carried out by Alex Wilshaw and Ben Copsey, with the help of Peterson Eperon, Pedro Ebeya, Francis Lowan and Simon Dakacho Eperon.

The work at KL4 mapped the surface extension to the site along the ridge (East-West), as well as from the plain to the top of the ridge surface (North-South). From the geological trenches, it became clear that the ridge was probably formed by the deflation of the surrounding plains through erosion, thus representing an inverted topographic feature. Accordingly, the fossil fragments (including many remains of a single hippopotamus) and occasional lithics scattered up to 20 metres north of the ridge on the surface of the plain are probably deflated pieces in original horizontal position, and thus an extension of the site rather than recent wash from the top of the ridge (as originally thought). The re-fitting of a number of hippopotamus fragments found in this area supports this conclusion. Besides the geological trenches, an area of 3 x 3 m was opened and excavated, with all remains sieved. These revealed that (a) the depth of archaeological remains is very shallow, mostly between 2-5 cm, thus representing a sub-surface stratigraphy; (b) that the buried levels are significantly less dense than the surface, thus indicating that substantial deflation has taken place over most of the site; and (c) that no significant differences exist between the surface and buried archaeological materials, thus suggesting that the site represents an archaeological event – of unknown duration or frequency, rather than a time-transgressive occupation.

A few, very scattered and fragmentary human remains were found at KL4, some of which may belong to the three burials excavated in 2011. Two new, partially exposed burials were found to the west of the main area of the site. One of these remains in situ; the other was excavated to reveal a male individual in extended position, lying on its side, with the head to the South. Three microliths were found associated with the burial. As was the case with the skeletons found in 2011, the bones are very fragile and poorly preserved once exposed. No burial pit was evident.

 Excavation of Nataruk 

The site of Nataruk is located approximately 5 km to the west of KL4. It was discovered by one of our Turkana field assistants (Pedro Ebeya) during the past year, who showed it to us on the first day of work. The number of fragmentary human remains on the surface, as well as the presence of partially exposed burials, in conjunction with the establishment of neighbouring homesteads made the excavation of this site a priority. The area is constantly trampled by large herds of goats that invariably break and damage the exposed remains. The work at Nataruk focused on (a) mapping the extent of the site and the distribution of fossil and archaeological remains; (b) the identification of all partially exposed human burials; and (c) the excavation of the latter.

 The main site of Nataruk covers an area of approximately 200 m EW x 100 m NS, consisting of a set of low-lying hills flanked by a dune to the South and another to the West. The former runs East-West for almost the entire extent of the site, reaching some 4 m above the site’s surface level. The low-lying hills that form the site are surrounded by gullies that drain in all directions away from the top, lying to a maximum of 2 m above such gullies. A diffused shell layer can be seen along the edge of these gullies, which is continuous with the shells and carbonated deposits found at sub-surface throughout the area.

Spatial distribution of finds at the site of Nataruk, 2012

The nature and distribution of finds shows that Nataruk was not a living site. Archaeological remains are rare over most of the site, although an area of greater concentration of lithics (mainly LSA microliths) was found above the human skeletons on the ridge. If the site was once the location of a foraging camp, it must have been an ephemeral occupation. Consistently, there are relatively few faunal remains, the latter representing mainly broken hippopotami and wild boar teeth, with occasional remains of bovids. Virtually no fish remains were found on the surface. By far the majority of materials at the site are human remains, mostly fragmentary, forming eroded scatters of varying horizontal extent that must have once been complete buried skeletons. Fragments of human remains have also washed extensively along the gullies, particularly to the North. The survey identified 27 human skeletons, some of which consisted of scattered surface fragments, some were partial skeletons, and some were complete. The eroded material was mapped and collected, and the 12 articulated skeletons excavated. Many people contributed to the excavation of the Nataruk skeletons, particularly Julie Lawrence, Holly Miller, Frances Rivera, Denis Misiko Mukhongo, Justus Edung, and Marta Mirazon Lahr, with the help of Michael Emusugut and Tot.

The Nataruk skeletal material awaits full preparation, cleaning and analysis. Preliminary sorting and cleaning was carried out at TBI in September 2012 with the assistance of Frances Rivera (LCHES), Denis Misiko Mukhongo (LCHES), Acacia Leakey (TBI), Timothy Ngundo (TBI), Sammy Eraidorot Lokorodi (TBI), and Ekai Ekes (TBI).

Geological and Spatial Survey of Natome

Natome was the first locality identified and studied by the team in the area, and has been the focus of several surveys in the past few years. The locality is extremely rich and geomorphologically complex, straddling the shoreline of the late Pleistocene/early Holocene lake PalaeoTurkana on a North to South transect, and the relative micro-stratigraphic position of the different shell layers and hills remains to be established. Current preliminary dates suggest that the lake was high between 12,000 and 7,000 BP, a 5,000 year window of shifting beaches and changing lake edge animal and human communities. To address the question of whether different parts of the site date to different phases of the last high lake, an extensive geological survey was carried out. This consisted of a series of geological trenches that extended from North to South from a hill-top to some 3 m below the surface of a dry river bed. The trenches were bridged stratigraphically through key markers – particular shell or organic-rich layers, logged and described, and sedimentary samples collected for OSL and radiocarbon dating, as well as Oxygen Isotope analysis. The work towards the definition, preparation and excavation of the Natome – and all other – geological trenches was supervised by Dr Aurelien Mounier, with the expert assistance of the ‘geo-fundi’ – James Lokuruka, Peter Amuk, Robert Ng’ichila and Peter Atadeit. All geological trenches (covering the range of altitudinal variation at Natome, as well as the trenches at KL3, KL4 and Nataruk) were logged and described at the end of the season by Prof Hema Achyuthan and Prof Robert Foley, with the help of Aurelien Mounier.

Further spatial surveys of the eroded hills of Natome were carried out, focusing on the northern end of the locality (Frances Rivera) and the areas surrounding the geological trenches (Aurelien Mounier), with the objective to continue the characterisation of the fauna exposed and the position of the ancient shoreline boundaries. As was the case in previous years, most of the material found deflated on the surface of the hill slopes consists of fragments of fish and hippopotami.

Palaeontological and Geological Survey of Kalakoel 3

The Kalakoel 3 (KL3) site is located to the West of KL1, across the dry bed of a seasonal river. From the perspective of an East to West transect, the eroded hills of KL1 give way to a sandy river bed with palm trees and bushes, with a western bank ranging between 1 and 1.5 m in height. The terrain west of the river is flat and sandy, with a sub-surface shell layer of similar constitution and colour to the late Pleistocene/early Holocene shell layers identified elsewhere in the area. Approximately 500 m to the west of the river bed, the sandy surface deposits disappear and give way to a deflated gravelly/rocky surface with the occasional patch of large, conglomerated oyster shells. A large surface of stromatolites is partially exposed at some points, while at others these are visible as they begin to erode just underneath the surface. The hard surface around the stromatolites and extending to the west (to a yet undefined extent) contains a dense assemblage of Middle Stone Age lithic artefacts and a few eroded fossil remains. The latter consist mainly of hippopotami, although elephant and bovid bones have also been identified. Minimum U-series dates on 5 fragments of hippopotamus bones obtained by Prof Rainer Grün in 2011 all point to a late Middle Pleistocene age for the material.

To begin the comprehensive survey, geological mapping and localised excavation of the KL3 locality was one of the objectives of the 2012 field season. However, given the excavation of the new Nataruk site and the overall aim to conclude the work on the late Pleistocene/early Holocene occupation of the area, the work at KL3 this season was scaled down. Nevertheless, three geo-trenches were excavated to expose the immediately underlying stratigraphic sequence and to obtain sedimentary samples for OSL dating. These trenches were located at the edge of the dry river bed to try to link stratigraphically the late Pleistocene sediments with those of Middle Pleistocene age, and at the edge of a gully to the north of the main stromatolite bed to expose the stromatolites in situ. A brief survey of the area by Dr M Mirazon Lahr, Justus Edung, Frances Rivera, and Denis Mukhongo, immediately to the west of the stromatolite beach revealed the presence of animal fossils at sub-surface; one of these (a buried hippopotamus humerus directly above MSA flakes) was the focus of a localised excavation to reveal the state of preservation of the material. A sample of the surface archaeological artefacts had been collected in 2011, so no further archaeological collection was made at this point.

Summary of 2012 Fieldwork

The first season of fieldwork in West Turkana of the In Africa Project was very successful. A small archaeological excavation of the Kalakoel 4 locality and characterizing its findings was carried out, and comprehensive stratigraphic sections at Natome were exposed from which samples for dating and other analyses could be obtained. The geological, palaeontological and archaeological study of the Middle Stone Age locality of KL3 continued, particularly in terms of the excavation of trenches for stratigraphic characterization and chronological sampling. A completely new locality, Nataruk, was surveyed and excavated, resulting in an important sample of human skeletal remains of late Pleistocene/early Holocene age.

The 2012 scientific field team:
  • Dr Marta Mirazon Lahr, LCHES, Univ of Cambridge (UK/Argentina; palaeoanthropologist)
  • Prof Robert A Foley, LCHES, Univ of Cambridge (UK; palaeoanthropologist)
  • Prof Hema Achyuthan, Geology, Anna Univ, Chennai, India (India; geologist)
  • Dr Anne Muigai, Jomo Kenyatta Univ (Kenya; biologist)
  • Dr Aurelien Mounier, LCHES, Univ of Cambridge (France; palaeoanthropologist)
  • Dr Holly Miller, LCHES, Univ of Cambridge (UK; archaeologist)
  • Denis Misiko Mukhongo, LCHES, Univ of Cambridge (Kenya; PhD student in Genetics)
  • Frances Rivera, LCHES, Univ of Cambridge (US; PhD student in Palaeoanthropology)
  • Alex Wilshaw, LCHES, Univ of Cambridge (UK; PhD student in Palaeoanthropology)
  • Ben Copsey, LCHES, Univ of Cambridge (UK; PhD student in Palaeolithic Archaeology)
  • Julie Lawrence, LCHES, Univ of Cambridge (UK; PhD student in Palaeoanthropology)
  • Justus Edung, NMK Lodwar (Kenya, Turkana; Field Researcher)
 The 2012 team of field assistants:
  • James Lokuruka, TBI (Kenya, Turkana)
  • Peter Amuk (Kenya, Turkana)
  • Peter Atadeit (Kenya, Turkana)
  • Pedro Ebeya (Kenya, Turkana)
  • Michael Emusugut (Kenya, Turkana)
  • Francis Lowan (Kenya, Turkana)
  • Robert Ng’ichila (Kenya, Turkana)
  • Simon Dakacho Eperon (Kenya, Turkana)
  • Peterson Kitui Eperon (Kenya, Turkana)
  • Tot (Kenya, Turkana)
The 2012 field camp support team:
  • James Suiyanka Oltimbao, Cook (Kenya)
  • Edwin Murungi, Driver (Kenya)
  • David Lomuria, Askari (Kenya, Turkana)
  • Musa, Askari (Kenya, Turkana)
  • Joseph Ekeno, Camp Assistant (Kenya, Turkana)
  • Joseph Erupe, Camp Assistant (Kenya, Turkana)
  • Joseph Lopua, Camp Assistant (Kenya, Turkana)
  • Robert Ng’irotin, Camp Assistant (Kenya, Turkana)