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2015-02-07 14:54:21   •   ID: 1216

LCTs From Isimila- Interaction between Man and Mammalian Macrofauna

Figure 1
The Isimila Acheulian Occupation Site in the Iringa Highlands of Tanzania was discovered in 1951 by  D.A Marclennanof, who on his way from Nairobi to Johannesburg, collected some tools from the site.

A first scientific report by van Riet Lowe, at that time the most eminent Prehistorian of South Africa, appeared already in 1951. The first Excavation work at Isimila was carried out 1957-1958 by Clark Howell, later followed by other Research Teams until 1968.

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. Given the time at which the U/Th was done, the results can only be regarded as a minimum age.

Correlations with extinct fauna from other East African localities together with ESR and OSL estimates now indicate that the Isimila Formation is considerably older and was deposited over a much longer time range than originally proposed.

The refined large cutting tools shown in Fig. 1-3 were originally found in the upper Lisalamagasi Member, dated with OSL now to 400-500 k.a. This suggests a correlation with the Acheulean at Kalambo Falls.

The LCTs of the upper beds are more refined than those found in the units of the lower Lukingi Member, now dated both by faunal correlations and ESR estimates to ca 500 and 900 k.a.

The site is in a short distance from Iringa town and is one of the richest finds of Paleolithic tools anywhere in the world. Nowadays the site is a Museum and  is reached by a hike through amazing eroded columns in nearby dry river gorge.

Figure 2
Made in the African Acheulian / LCT tool-making “tradition”, the handaxe in Figure 1 and the Cleaver in Figure 2 handaxe is 20 cm long.

Although oversized in comparison with most European stone tools of the same type, these LCTs were not unusually large, neither for the Isimila site where they were found, nor for similar tools at other East African ESA localities.

One reason for their large size is the nature of material of which they were made. Large blocks of rock (basalt, rhyolites, trachytes, phonolites, and other lavas) that were commonly available for use in many regions of East Africa during the ESA , yield large flakes which can be worked into large cutting tools.

The flint nodules used by prehistoric Europeans are often smaller. On the other hand, in East Africa during the Acheulian, quartz and chert-often in the form of erratics from stream channels-served for the manufacture of Light Duty tools which have accumulated through the erosion of many superimposed occupation levels.

However, many other intact occurrences do indeed contain impressive numbers of bifaces, as discoveries at the east African Pleistocene sites like Olorgesaille, Isenya, Kariandusi, Lewa and Melka Kunture, amply demonstrate.

Mary Leakey distinguished between the Acheulian and the Developed Oldowan at Olduvai Gorge upon the basis not only of technical features but also upon biface frequency, requiring that more than 50% of the tools in an assemblage were handaxes and cleavers to qualify an ensemble as Acheulian.

Many authors would now argue that the presence of even a single handaxe in an assemblage renders it Acheulian by evidencing that the makers of the artifacts mastered a three dimensional design.

Some similar Handaxes and Cleavers from the same site are shown in Figure 3 (Howell 1972):

Figure 3
Experimental investigation clearly shows that “large cutting tools” (handaxes and cleavers) are well suited for the task of carcass dismemberment and defleshing, but artifact associations do not unequivocally support the early assumption that they were butchery implements.

On the one hand, association of bifaces with megafaunal remains at Torralba and Ambrona, Spain, for example, does support their use in butchery, as do artifact association, refitting, and microwear at Boxgrove, England.

On the other hand, many Middle Pleistocene single carcass occurrences that appear to represent butchery episodes have few handaxes or lack bifaces altogether.

These include the Elephas recki skeletons from Member 1 at Olorgesaille, Kenya , and from FLKN at in Bed I at Olduvai Gorge, Tanzania, and the partially dismembered elephant from the contact between the Chiwondo and Chitimwe Formations at Mwanganda, Malawi.

Partially dismembered Hippopotamus skeletons have been discovered in the Lukingi Member at Isimila, Tanzania, and from Gadeb 8F, Ethiopia.

The artifact assemblages in all these occurrences are made up primarily of small flakes, cores, and scrapers, with the addition of rare bifaces or heavy duty implements. No doubt the handaxe, a long-lived and geographically widespread implement, served a variety of purposes in the many different contexts in which it was used.

Microwear analysis is complicated on east African handaxes, most of which are made of lava.

Anyhow, studies of usewear on handaxes found elsewhere serve to confirm the impression that the handaxe was a multipurpose implement.



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