2015-02-07 15:58:41 • ID: 1217
A heavy LCT-Flake Cleaver from Isimila / Tansania
This is a large, perfect, "six-hit"- cleaver from Isimila / Tansania made of Mylonite, a cataclastic microcrystalline rock with a finely divided quartz groundmass of various types and colors (Howell et al. 1962, 64).
The Isimila mylonite has good knapping qualities. The best outcrops of this acidic-volcanic-metamorphic rock are found 6-8 km west of Isimila, but the formation itself can be traced closer to the site.
Isimila is situated 21 km from the town of Iringa in the southern highlands of Tanzania and is situated about 1631 m Elevation above Sea Level. D. A. Maclennan (South Africa) discovered the site in 1951 during a car journey from Nairobi to Johannesburg.
F. C. Howell, M. R. Kleindienst and G. C. Cole excavated the site for a total of 7 months during 1957–58. An additional season of excavation, directed by Hansen and Keller, took place in 1969, and a small-scale excavation was undertaken by Kleindienst in 1970.
The Isimila stream runs through a small valley that was created by tectonic movement. During the Pleistocene the outlet of the basin was partially blocked, creating an elongated body of water. This body comprised a combination of marshes and small ponds, sometimes with an overflow.
The basin was filled by alternating bands of fine, level-bedded gray-green clay and coarser sandy sediments, which Pickering named „Isimila beds'“.
The depth of the sediments is more than 18 m, and the excavators estimated them to have accumulated over a „few thousand years at most'“ (Howell 1961; Howell et al. 1962).
Five distinct beds of coarser sands were identified in the Isimila beds, separated by layers of finer silty clay sediments - a Palaeolithic Pompeij.
The main “living floors” and the largest quantities of artifacts originate in the upper layers. As most artifacts are in mint condition and no evidence of water or other means of transport has been observed, it has been suggested that differences in artifact distribution within the sediments of the various sites should be attributed to human activity.
It is still worth while to read the passages of Binfords "Bones: Ancient Men and Modern Myths" about the problems reconstructing ancient landscapes at the Isimila site. The short duration of the Isimila bed’s sedimentation process, estimated to be a few thousand years, should be emphasized (Howell et al. 1962), although Hansen and Keller (1971) have questioned this interpretation.
Typological comparisons with the Late Acheulian assemblages of Olorgesaillie and Kalambo Falls have led Kleindienst to define Isimila as being younger than both (Howell and Clark 1963)-but nowadays we know that these sites are considerably older than suggested during the 1960ies and typological considerations have lost their credebility.
Early Uranium series, when the method was still in its infancy, dating of bones from Sand 4 have yielded a date of 260 k.a. (+40–70 k.a.) but these dates are only a rough estimate. Many scholars feel that Isimila could well be 400 k.a. or even 1 Ma old.
Given the time at which the U/Th was done, the results can only be regarded as a minimum age. B. Blackwell is working on ESR dating. A preliminary report is in progress (Maxim Kleindienst Personal communication 3/2021).
New excavations took place during the last years, focused on landscape Archaeology and advanced dating techniques.
One of the primary reasons for renewed interest for Isimila is the unique artefact record for a site outside the Rift Valley system present in both primary and secondary contexts consisting of thousands of handaxes - including enigmatic giant handaxes, like the one shown here.
Despite the international significance of Isimila, the archaeology, chronology, taphonomy and geomorphology of the site remain poorly understood, and therefore in urgent need of re-evaluation.
The earliest Acheulian in East Africa is dated to ca 1.75 million years ago and is well documented at Kokiselei in Kenya, at FLK West (Olduvai Gorge, Tanzania) and at Konso and Gona in Ethiopia.
The Acheulian of East Africa, which persisted for over one and a half million years, is attested in diverse environments and over wide geographical expanses. The hallmark of many Acheulian sites in this region are Large Cutting Tools (LCTs), made from “giant cores” primarily for the production of handaxes and cleavers.
Even the earliest assemblages from the Konso sites consist of ‘large cutting tools’ (LCTs) including unifacially and bifacially shaped handaxes, Cleavers and picks, as well as Mode I (Oldowan) cores, and débitage.
Anyhow, although technologically similar, at Konso a majority of the bifaces were made on flake blanks, whereas at the contemporaneous Gona site they were made equally on cobbles as well as large flakes (>10 cm).
This mode of production was first recognized by Isaac during the 1960ies. LCTs very likely emerged in East Africa but have been reported from a wide range of areas, spanning South Africa, Israel (GBY), the Caucasus Region, Eastern Georgia to India (and even beyond the Movius line) to the Iberian Peninsula and Southern France.
It is only in Europe north of the Pyrenees and the Garonne valley that a substantial Acheulian presence not accompanied by LCT industries is present.
Sharon recently compared assemblages from geographically diverse sites characterized by the production of LCTs based on large flakes (defined arbitrary as flakes over 10 cm in maximal diameter) in an attempt to assess their technological, morphological, and typological suitability for grouping together as a common stage within the Acheulian techno-complex.
Different techniques of flake (blank) removal from larger clasts are described from the LCT Acheulian. These include bifacial and sliced slab method from giant cores, éclat entame (cobble opening flake),Tabelbala-Tachenghit techniques, Kombewa methods and the Victoria West technique.
It is a striking and humbling fact that we still do not know precisely when certain technological milestones and cognitive horizons were first reached.
Sharon noted that there appears to have been a shift from LCT-industies industries to non LCT ensembles between 800- 500 k.a.
Given the insufficient chronological control of many African sites this seems to be somewhat hasty conclusion, regarding the late age for some late Middle Pleistocene East African LCT-Acheulian Ensembles.
In addition, other regions, such as India, have LCT-cleavers that were produced along with broad-tipped handaxes at 500 k.a. and later. The same holds tue for several LCT-ensembles of Spain, dated to the late Middle Pleistocene -see 2187 .
The Nile Valley and the Oases in the western Sahara seem to have their own trajectories towards the Acheulian. The Acheulian culture was originally defined and categorized in accordance with finds from W-Europe, which comprise many types of handaxes, produced almost exclusively from flint nodules and river cobbles.
It comes without surprise that the special features of the African Acheulian came in focus only after the WW II when Africanists began to work with this culture from a post-colonial and anti-Eurocentric view
Resources and images in full resolution:
- Image: isimila-aggsbach-662x1024.jpg
- Image: ciidfjdd.jpg
- Extern Link: www.sciencedirect.com…S0047248414001559
- Extern Link: arad.mscc.huji.ac.il…001744074.pdf
- Extern Link: www.nature.com…s41598-018-21320-1
- Extern Link: www.researchgate.net…223170604_The_impact_of_raw_material_on_Acheulian_large_flake_production
- Extern Link: www.researchgate.net…235381135_The_characteristics_and_chronology_of_the_earliest_Acheulean_at_Konso_Ethiopia
- Extern Link: www.researchgate.net…327073339_The_Early_Acheulean_16-12_Ma_from_Gona_Ethiopia_Issues_related_to_the_Emergence_of_the_Acheulean_in_Africa
- Extern Link: www.researchgate.net…339721261_Co-occurrence_of_Acheulian_and_Oldowan_artifacts_with_Homo_erectus_cranial_fossils_from_Gona_Afar_Ethiopia