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2021-11-07 09:17:33   •   ID: 2278

Olduvai / Oldupai Gorge: A Handaxe from lower Bed II

Figure 1 Panorama
Figure 2 Monolith
Figure 1: Photographic panorama of Olduvai Gorge / Tanzania (Source: Photo: Noel Feans; Permission: Creative Commons Attribution 2.0 Generic license); Figure 2: the famous "Monolith" with superimposed several beds of the Fossil and Artifact bearing layers. (Source and text: D. Gordon E. Robertson; Permission: Creative Commons Attribution 2.0 Generic license).

Currently and by (40)Ar/(39)Ar dating of tuffs and lavas of Pleistocene volcanic and sedimentary sequence of Olduvai Bed I is dated to 2,1- 1,8 mya, Bed II to 1,8 to 1,15 mya, Bed III to 1,15 mya-800 k.a., Bed IV is about 800-600 k.a.old and the the Masek Beds were dated from 600 to 400 k.a. The Ndutu Beds are about 400-32 k.a.old and the Naisiusiu Beds are younger than 15,k.a.

Figure 3, 4 and 5: An Almond shaped, thick and biconvex hand axe (13x8x5 cm) from the Bed II / Olduvai from my own Collection: Made from Volcanic Rock this relatively small and massive core tool is completely bifacially flaked, with deep flake scars and slightly sinuous edges (Figure 5). Breuil and Bordes would have called such a Handaxe "Biface Abbevillien".

Although relatively short, the Bifaces dimensions are still in the lower size range of the Upper Bed II bifaces. Almost identical pieces from this bed were recently described from the TK site in Bed II, dated to ca. 1,5 ± 0,035 Mya, (Santonja et al. 2016). This piece, together with an early Handaxe from South Africa- see 2227 is still one of the oldest Bifaces from my collection.

The Olduvai Basin in northern Tanzania is part of the East African Rift System- see 1474 , and offers an unique, more than 2 mya long record of sediments, flora, fauna and artifacts over the stratigraphic succession. Moreover, many sites are in-situ and offer preferable opportunities for Archeological prospection.

Figure 3 Olduvai
Although the fluvial and lacustrine deposits are exposed in the basin over ca 250 km2, most of the archeological sites are found within in a relatively small area (about 7 km2) centered on the junction of the Main Gorge and Side Gorge.

60 years ago Louis and Mary Leakey drew the attention to Olduvai Gorge, by discovering there hominin fossils of both Australopithecus boisei and Homo habilis in Bed I (Leakey 1959). The position of Homo habilis within human evolution initially remained highly controversial and it took more than a decade for the taxon to be generally accepted after more complete new skeletal finds. Although OH 7 is not the first fossil find of Homo habilis, it was selected as a typical representative of its species.

Earlier, in 1959, Heslon Mukiri, an associate of the Leakeys, came across a molar and a premolar at another site in Bed I. But the two teeth were first put aside by Mary Leakey's skull find OH 5 (Zinjanthropus boisei) a few weeks later.

Later cranial remains of Homo Erectus (s.l) (or Homo Ergaster) were found in Bed II (OH 9 and 12). Since then the attention was always directed towards the Record of Bed I and II (roughly dated to 2.1–1.1 Mya) while Bed III and IV, and the overlying Matakaba and Masek Beds were rather neglected.

This can be explained by the fact, that Bed II ist the most complex formation from an Archeological standpoint, especially by the inter-stratification of "Olduvan" and "Acheulian" sites and the preservation of larger quantities of faunal remains.

Definition of the Acheulian: While M. Leakey (1971) defined an Acheulian by the presence of at least 40% Handaxes in an ensemble, later investigators have emphasized more on technological aspects.

Currently,an Acheulian is considered to exist by the evidence of LCT technology and mastery and use of three-dimensional (core) volumes.

The Acheulian was the first standardized tradition of toolmaking, characterized by a volumetric bifacial concept, indicating a higher level of cognitive competence of their makers compared with their predecessors or contemporary Hominins.

I have earlier reported about the dilemma of connecting stone tool techniques and typology with already known Hominins- see: 2232

In addition, for a broader definition of the Acheulian, improved façonnage for biface, pic and cleaver manufacture and preference for discoid technology among small débitage methods should be added.

Using an flexible and purely technological approach, in the final consequence, an Acheulian without a single Handaxe is thus possible (S.Y Policarpo et al. 2018). It remains to be proven whether this radical position is sustainable

Figure 4 Olduvai
Refinement of Handaxes over time? Originally, L.S.B. Leakey developed a 9-stage model of biface evolution that was intended to demonstrate an increasing sophistication of tool making between Bed II and the Masek Beds.

Shipton recently showed, that Leakey's illustrations of the Olduvai material were not biased, but indeed relatively representative for the Succession at Olduvai. Therefore Leakey was not simply driven by the evolutionary concepts of his time but provided a solid foundation for the analysis of the local archaeological development of handaxe Cultures at Olduvai (Shipton 2018).

However, we must keep in mind that the trend toward increasing refinement of the bifaces from lower to upper strata, refers to their totality. Of course, this does not apply to each individual case: There are relatively refined and symmetric Handaxes, similar to our example in Bed II, but of course they are in the minority.

Further Examples of early Handaxe Sophistication come from FLK West and from TK, the latter located in the upper part of Olduvai Bed II, dating close to 1,5 mya (Domínguez-Rodrigo et al. 2013).

In addition the trend of increasing Handaxe refinement, that Shipton found in Olduvai, was not confirmed at other large East African sites (Shipton 2018) - more about the issue- see: 2030

Figure 6, shows an archaic looking hand axe from southern Italy, which is about only 300 k.a. old and looks just as archaic as the artifact presented in this post. The same holds true from a Middle Pleistocene LTC Handaxe from Isimila in Figure 7.

Many of the bifaces from M. Leakey's monograph on Bed III-IV appear as "archaic" as if they originated from the lower levels of Bed II.

On the other hand, we know other refined and symmetrical handaxe from Bed II in Olduvay . Some of them can be seen at the web-page of the British Museum in London- see here: BM-Handaxe .

Remarks on Bed II: This post focuses on the early Acheulian of Bed II, the source of the single Handaxe of this post and the area of recent Archeological Activities in the Post-Leakey area.

These new excavations may be characterized by the detection and evaluation of high resolution stratigraphies, the use of advanced sedimentary geology and the use of advanced isotope geochemistry resulting in high-resolution paleoenvironmental reconstruction.

It should be mentioned, that lateral discontinuities and the reworking and alteration of volcanic glass makes makes dating of Bed II less precise than that of Bed I.

Figure 5 Olduvai
Geochemical “fingerprints” from 5 marker tuffs and the so called "Bird Print Tuff" plus several local tephra of Bed II have been evaluated recently, and have major implications for the Oldowan–Acheulean transition by improving the correlation of different stratigraphic sections (McHenry et al. 2018).

When Bed II (2,17-1,2 mya) was formed, a large paleo lake (Paleolake Olduvai), that appeared during several Volcanic events of the late Pliocene, receded during the increasing aridity alongside the Lower-Middle Bed II in a now semiarid Environment, new raw materials became available at the lake shores.

Instead of quartzite, quartz, volcanic rocks including basalt - chert / flint , with its well known properties became for the first time accessible for the Hominins but was still used in low quantities.

Theoretically Chert is often suggested being a somewhat more optimal raw material by its homogeneity, ability to develop high quality conchoidal fracture, and the production of exceptionally sharp edges.

Anyhow, compared to other raw materials, the flake edges are often less less durable. This may have necessitated more frequent retouching to strengthen the edges of chert flakes - see 1504 , which may one factor, that even in Bed IV, quartzite Handaxes are common.

Maybe mentality change of later Hominins brought Flint Handaxes into the „Pool Position“ known from the Acheulian of continental West Europe and the UK.

At ca 1,7-1,5 mya Hominins settled not only at the margins of shrinking Paleo Lake Olduvai but also at river channels and on permanent groundwater-fed springs associated with archaeological sites (Ashley et al. 2010).- see 1477 for the central role of water supply in Human Prehistory.

Mercader et al. (2021) demonstrated that early Hominins created a "homogenous technology to utilize diverse, rapidly changing environments that ranged from fern meadows to woodland mosaics, naturally burned landscapes, to lakeside woodland/palm groves as well as hyperxeric steppes."

In search of Early Acheulian in-situ sites: To evaluate hominin behavior during this evolutionary key time with respect to procuring food, water, and materials for stone tools, as well as hominin adaptation to climate and paleoenvironmental change it is extremely important to detect taphonomic intact in-situ sites with their faunal remains.

Note that Core and Flake Industries-see here: 1663 , here 1678 , and here: 1176 -the (Olduvan) will not further discussed here -they have been detected from the base of Bed I until the Middle Bed II and are interstratified between the early Acheulian sites.

As can be seen from the extensive literature about the East African Olduvan, the division into Early and Late Olduvan (Types A and B), coined by Mary Leakey, has now been abandoned by most of the researchers- for example by Gallotti at Melka Kunture, with good arguments.

Currently, researchers prefer the model of a rather rapid transition from the Olduvan to the Early Acheulian, for example at At Gona, Ethiopia at 1,77 mya (Semaw at al. 2009).

Figure 6 Venosa
It seems that the start and dissemination of the Acheulian over the old world followed exactly Roger‘s „Diffusion of Inventions“ paradigm of 1962, which too often does not really fit to the Palaeolithic record.

Not only at Olduvai Gorge, but also at other early Acheulian sites in East Africa, there is usually a lack of association between lithics and faunal remains or they are even devoid of fauna.

The very early Acheulian, dated to ca 1,7 mya, of Konso Gardula (Ethiopia), Kokiselei (West Turkana, Kenya) and later early Acheulian sites at Koobi Fora, Olorgesailie and Peninj are unfortunately no exception from this general rule.

All the more important is the early 1.7 Million-Year-Old Site of FLK West, where simple and developed handaxes are simultaneously associated with well preserved fauna in the context of unambiguous butchering activities. The “Nature”-paper in the external link-section of the post will give you a rather good impression about the advanced handaxe technology

FLK West as an Example of Acheulian / Olduvan Interstratification: FLK West consists of a sequence of sand, silt, conglomerates and tufa. The lowest Marker Tuff (Tuff FLKWa) is about 1,69 mya old.

Six find horizons are incorporated into this sequence. At the base there are two layers of an early Acheulian based on LCTs and on top of them there are four strata with core and flake ensembles ("Olduvan"). This sequence ends with an Upper Tuff (FLKWb), dated to ca 1,66 mya.

This results over a narrow time window, in terms of a geologic definition, with evidence of two contemporaneous archaeological entities at a high stratigraphic resolution is a true stroke of luck for Prehistory (Sánchez-Yustos Policarpo et al. 2018).

The excavators stated that "The differences noted in the absence/presence and frequency of LCTs may be explained in occupational terms, while the similarities in raw material selection, core reduction and flake retouching patterns indicate homogeneous cultural decisions and cognitive skills. We conclude that these assemblages were likely formed by the same hominin group or taxon and, therefore, the assemblage variability registered would correspond to different expressions of the same economic structure.". This is a convincing good-by to cultural-historical approaches at the dawn of humanity.

At the same geological level, but mainly more recent in Bed II, further early Acheulian sites are located between Tuff IIA and Tuff IID within a time frame between 1,66 and 1,44 mya.

The most important and recently extensively studied Early Acheulian sites in this area besides FLK, were already first evaluated by the Leakey Family more than 60 years ago. These are: MNK main; SHK; SC West and EFHR (de la Torre 2016).

Man the Butcher: Evidence for Early meat consumption: This issue requires evidence that changes on fossil bones are man-made and not caused by other taphonomic processes. Of course, the skeletal remains of most interest for Pleistocene hominins and Researchers are preferably the selective accumulation of meat and bone marrow rich parts.

The most important issues are the identification of cut marks, tooth marks, percussion marks, and natural marks (biochemical and abrasion marks). The methodology is described in M. Domınguez-Rodrigo et al. (2009)

Once the presence of cut-marks and percussion marks can be established, it must be proven by rigorous investigations that hominids were the first who had access to the carcass.

Although Olduvai Gorge provided strong evidence of effective scavenging and hunting (?), paleoanthropologist assume that the hominids who inhabited the area between 2,1 and 1,8 mya spent most of their time gathering wild plants such as berries, tubers, and roots.

Furthermore, taphonomic re-analyses of Olduvai Bed I sites, including the Archeofaunal remains and stone tools, and most of Olduvai Bed II localities evidenced that with the exception of FLK Zinj (Bed I), and the BK-site (Bed II) these areas were palimpsests with minimal hominin input, formed by multiple agencies - for example the SHK Main Site (Domınguez-Rodrigo et al. 2007).

The oldest but sparse evidence for active meat consumption comes from the Olduvan Site El Kherba in Algeria see- 2111 ; (Sanhouni et al. 2013) from the upper parts of a 1,8-2,4 mya old succession and from the site of FLK North at Olduvai Gorge (Domínguez-Rodrigo et al. 2010) dated to 1,8mya.

In the Afar Triangle in Ethiopia, both Acheulian and Oldowan artifacts, Homo erectus crania and signs of active defleshing and disarticulation on bones were associated ca. 1,6 to 1,5 Ma ago at Dana Aoule North (DAN5) archaeological site at Gona.

Thus, around 1.8 mya, megafaunal meat consumption does not seem to have have played a major role in the diet of hominins.

Another line of evidence comes from comparative studies of the closest relative of humans: the chimpanzee.

The diet of the great apes consists of only about 5% meat. Even today's hunter-gatherers maintain a diet that is not characterized by large amounts of meat.

The majority of the calories needed are of plant origin. Anyhow, one should be cautious with such analogies.

A clear trend to butchering activities is detectable at Olduvai since ca 1,5 mya (after middle Bed II). Both cut-and percussion marks on bones, which indicate a primary access by hominins to meat, and a tight association of stone tools and butchered bones became much more common. Important butchering sites: BK, TK, FLK-West and SHK, are dated between 1.3 and 1.7 Ma. respectively.

Butchering (and Hunt?) is most strikingly demonstrated by recent finds at Site BK; Upper Bed I: " the present study indicates that BK should be added to the small number of Plio-Pleistocene sites where hominins contributed to the faunal assemblage and where primary access to carcasses can be inferred through taphonomic analyses.

The high frequencies of cut marks and percussion marks from such a small excavation suggest that BK could potentially contain the largest number of hominin-modified bones of all known Lower Pleistocene sites in Africa. If one 10 m x 3 m trench has produced a sample of hominin-modified bone that is comparable to the 300 m2 excavation at FLK Zinj, what could a similarly large excavation at BK produce?

This calls for future research at the site in order to expand the excavation area. In addition, this would allow the collection of more information on site functionality, given its re-occupation over such a vast amount of time. (M. Domınguez-Rodrigo et al.2009).

These results suggest that the the animals were actively hunted, but a direct proof for this theory, as for example for Schöningen / Northern Germany for the time period around 300 k.a., unfortunately does not exist so far for Olduvai around 1.5 mya.

However, the BK-site cannot be interpreted simply as a "home camp," as proposed in the 1960s. In this case, there is a clear need to develop new hypotheses and models to interpret such central-place sites.

Meat Consumption and Brain Size-a valid Master Narrative? The evolutionary success of Homo compared to Paranthropus is currently in part explained by their differences in food intake.

Paranthropus was mainly a herbivore, while Homo sp. is suggested to be mainly a a carnivore.(Foley 2001). There is a broad consensus that the habitual consumption of large quantities of meat, especially by the killing of available Megafauna by hominins, was a significant evolutionary step (M. Domínguez-Rodrigoet a. 2013).

Figure 7 Isimila
It should be noted that numerous other hypotheses (e.g. the influence of environmental, demographic, social- especially cost-signaling mechanisms, and technological factors) have also tested (Will et al. 2021). I personally assume that, as always for complex biological processes, increasing Brain Volumes were the consequences of multifactorial process.

The influence of Meat Consumption on increasing Brains appears as a conceivable narrative but has not yet been quantitatively verified in depth. At least there is some evidence in Bed II at Olduvai that could support the hypothesis, mainly at the BK-site (see above).

The hypothesis assumes that nutrient rich meat made Homo grow taller and smarter. Meat consumption increased the rate of encephalization.

The enlargement of the brain is something that makes us human, and for this it is necessary to provide substances that enable the body to build and operate the oversized brain of Homo sp. compared to his forerunners.

During Brain maturation it was necessary to have the appropriate proteins and fatty acids that form the brain mass. And this must be have achieved rather quickly, because after birth our Neurons mature very fast and no significant number of brain cells is added during later lifetime.

Stone and Bone tools improved a more rapid carcass dismemberment, whether the animals are killed by our species or succumbed by prey predators. In other words these craft skills transformed Homo into a more successful scavenger or even hunter.

Figure 7 shows an impressive 20 cm long LCT-Handaxe from the Middle (?) Pleistocene site of Isimila, certainly very useful in the hard work of rapidly dissect large carcasses -further information about the Isimila site-see here: 1217 .

Artifacts could have increase hunting success, but the timing of active Hunting remains a controversial issue during the early Pleistocene and may be rather a marginal issue in the context of successfully getting large quantities of meat-the decisive factor regardless of the methods that were used..

These activities, in turn, required a better organization of the processing of meat, bones and skins, which in turn changed the social structure of our ancestors. The more specialized knowledge they acquired, the more effective tools they could invent, which in turn may have created resources that could feed larger communities.

While Homo habilis, was barely able to compete with larger herbivores, his success depended on rapid detection of carcasses, their successful defense against other predators and their rapid removal to saver areas.

On the other hand, Homo erectus could possibly successfully hunt a few hundred thousand years later Elephants, rhinoceroses, hippopotami, zebras, giraffes of his African homeland (see below).

Interestingly a manual proximal phalanx, > 1,84 mya old from an unknown Hominin (OH 86)- maybe from an early Homo Erectus- was recently described from Bed I at Olduvai, which led to the reconstruction of a quasi modern human-like hand, suggesting, that a third Hominin co-existed with Paranthropus boisei and Homo habilis at Olduvai during Bed I times.

Since in the case of success of fresh carcasses, immediately enormous quantities of meat were available, which in the warm climate rotted fast, humans had to develop techniques for the further processing and preservation.

The decisive step in this process may have been the mastery of fire. Fire made it possible to preserve large quantities of meat. At the same time, roasting or boiling facilitated the enzymatic digestion of food, which in turn provided the eaters with more nutrients for an expanding community. And around the campfires, the groups developed a skill that allowed them to further optimize their hunting success: language.

Anyhow, the habitual use of fire is dated not earlier than 1 mya-see: 1692 , and this issue is actually far from being resolved.

In this post I have just reported just a few results from the current excavations- think on what will be still detected during the next decenia- I am convinced that the new facts will be overwhelming for all lovers of the Palaeolithic…….

Suggested Reading:

R. Gallotti and M. Mussi (Ed): Emergence of the Acheulean in East Africa and Beyond. Contributions in Honor of Jean Chavaillon; 2008

L. S. B. Leakey: Olduvai Gorge: Volume 1; 1965

MD Leakey: Olduvai Gorge: Volume 3 ; 1973

MD Leakey: Olduvai Gorge: Volume 5 ; 1985

Proveniance: Collection Baronetti / Milano (IT) Donation: L.S.B Leakey



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