the early stone age lithic assemblages of gadeb (ethiopia) and the developed oldowan/early acheulean...

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Journal of Human Evolution 60 (2011) 768e812

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Journal of Human Evolution

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The Early Stone Age lithic assemblages of Gadeb (Ethiopia) and the DevelopedOldowanearly Acheulean in East Africa

Ignacio de la TorreInstitute of Archaeology University College London 31-34 Gordon Square WC1H0PY London UK

a r t i c l e i n f o

Article historyReceived 8 August 2010Accepted 17 January 2011

KeywordsAcheulean originsDeveloped OldowanEast AfricaLithic technologyLarge Cutting Tools (LCT)

E-mail address itorreuclacuk

0047-2484$ e see front matter 2011 Elsevier Ltddoi101016jjhevol201101009

a b s t r a c t

The Early Stone Age sites of Gadeb (Ethiopian South-East Plateau) were excavated under the direction ofDesmond Clark in the 1970s Dated to between 145 and 07 Ma Gadeb proved that humans had alreadyoccupied high altitude areas in the Lower Pleistocene Despite the importance of the Gadeb sites theirlithic assemblages were never published in detail and no review of the stone tools has ever beenreported since the original 1970s study This paper updates the information available on Gadeb bypresenting a systematic review of the lithic technology of several assemblages The objectives are toevaluate the technological skills of Gadeb knappers and to contextualize them into the current discussionof the origins of the Acheulean and its possible coexistence with the so-called Developed Oldowan inEast Africa

2011 Elsevier Ltd All rights reserved

Introduction

The region of the UpperWebi-Shebelle (East-Central Ethiopia) isone of the earliest paleoanthropological areas ever discovered inAfrica The expedition of Bourg de Bozas visited this regionincluding the then called Ghedeb in 1901 and Brumpt collectedEarly Stone Agematerial that would eventually be studied by Breuiland Kelley (1936) During World War II Desmond Clark visited thisarea and described the sedimentary deposits of the Upper WebiShebele in detail (Clark 1954) However this and a subsequent visitin the 1960s by Bonnefille et al (1970) did not materialize intoexcavations Full scale excavations in Gadeb were conducted in1975 and 1977 under a project led by Desmond Clark in eastern-central Ethiopia but did not continue further In 1990 limitedfieldwork conducted in the area focused on the sampling ofdeposits for stratigraphic correlations (Haileab and Brown 1994)No further fieldwork has since been reported probably due to thedamming of the Upper Webi Shebele which in the 1980s partiallyflooded the sediments At present some of the deposits are stillunder water although part of the sedimentary sequence is exposed(personal observation Fig 1F and G)

Large scale excavations by Desmond Clark led to a number ofstudies of the lithics (Kurashina 1978 1987 Clark and Kurashina1979a 1979b Clark 1980 1987) geology (Williams et al 1979Assefa et al 1982 Eberz et al 1988) and environment (Bonnefille

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1983) Work in Gadeb has had considerable influence on recentliterature and references to the sequence of Gadeb are common inEarly Stone Age publications of the last few decades (eg Stiles1980 Isaac 1981 1982 1984 Klein 1983 Binford 1985 Rocheet al 1988 James 1989 Feacuteblot-Augustins 1990 Potts 1991Bar-Yosef and Goren-Inbar 1993 Gowlett 1993 Schick and Toth1994 Sahnouni 1998 McBrearty 2001 Goren-Inbar et al 2002Semaw et al 2009)

The Gadeb record has contributed to a variety of paleoanthro-pological discussions For example Clark and Kurashina (1979a)emphasized the importance of Gadeb as the earliest evidence ofhuman occupation in high altitudes a point also highlighted byRoche et al (1988) The presence of some obsidian handaxesconsidered to be imported from a source 100 km away (Clark andKurashina 1979a) has also been mentioned as early evidence oflong distance transfer of rawmaterials (eg Feacuteblot-Augustins 1990)Documentation of burned rocks in Gadeb 8E (Barbetti et al 1980)has been repeatedly claimed as possible early evidence for the use offire (Gowlett et al 1981 James 1989 Bellomo 1993) Likewise thepartial skeleton of a hippopotamus in Gadeb 8F was interpreted asan early case of a butchery site (Clark and Kurashina 1979a Clark1987) and referred to as such by other authors (Isaac 1984McBrearty 2001) Finally Gadeb is also known for the purportedinter-stratification of Developed Oldowan and Acheulean sitesthroughout the sequence (Clark and Kurashina 1979a) a claim thathas been widely discussed in recent years (Stiles 1980 Isaac 1981Binford 1985 Potts 1991 Bar-Yosef and Goren-Inbar 1993 Schickand Toth 1994 Kyara 1999 de la Torre 2008)

Figure 1 A) Location of Gadeb sites in Ethiopia B) Digital Terrain Model of the Gadeb plain with position of Localities 2 and 8 C) General stratigraphy of the Gadeb sequence(adapted from Eberz et al 1988) D) and E) Stratigraphic sequence in Locality 8 and Locality 2 (adapted from Williams et al 1979) F) and G) Localities 8 and 2 respectively in 2008(photos by the author)

I de la Torre Journal of Human Evolution 60 (2011) 768e812 769

Despite regular referencing to Gadeb in recent literature on theEast African Early Stone Age no revision of the lithic assemblageshas been carried out since the original studies by Clark and Kura-shina in the 1970s In fact the only systematic account of the Gadeb

assemblages (Kurashina 1978) was never published and no otherdetailed reports of the lithics were made available This paper aimsto update information about these sites through a full analysis oflithics from all the so-called Developed Oldowan assemblages

I de la Torre Journal of Human Evolution 60 (2011) 768e812770

(Gadeb 2E 2B 2C and 8F) which are compared with the Acheuleansite of Gadeb 8D Based on a technological approach which confersgreat importance to qualitative descriptions and graphic illustra-tion of lithics the objective of this paper is to present a systematicreport of each assemblage assess the effects of post-depositionalprocesses on the sites evaluate the knapping skills involved anddiscuss the relevance of the Gadeb assemblages in the broadercontext of Early Pleistocene technologies in East Africa

Geological and chronostratigraphic background

The Gadeb archaeological sites are located in the upper reachesof the Webi Shebele River on the Ethiopian South-East Plateaubetween the Bale and Kakka Mountains (Fig 1) At elevations of2300e2400 m above sea level the Webi Shebele meanders acrossthe Gadeb plain for approximately 60 km and cuts through a seriesof old lake and fluvial sediments regularly interbedded withvolcanic ash deposits The sedimentary sequence begins with theGadeb Formation (Assefa et al 1982) composed of lacustrineclaystones and diatomites Lake Gadeb was formed 271 Ma whenbasaltic lavas dammed the upper Webi Shebele (Williams et al1979) It is estimated that this lake occupied a shallow basin of30 10 km in extent (Clark and Kurashina 1979b) and was at least40 m deep (Williams et al 1979) Diatomites silt mud and clayswith interbedded sands and ash characterize this gt30 m thickGadeb Formation (Assefa et al 1982 Eberz et al 1988) which hada cooler climate than at present (Bonnefille 1983) The GadebFormation (Fig 1) is overlain by the 10 m thick Adaba Formation(Assefa et al 1982) composed of weathered ash beds beneath anignimbrite dated by KAr at 235 Ma which caps the lacustrinesequence (Williams et al 1979 Eberz et al 1988)

This welded tuff or Adaba ignimbrite is overlain by the Mio GoroFormation (Assefa et al 1982) inwhich a pumice mudflow from thebase of the sequence yielded a KAr age of 145Ma (Eberz et al1988)This suggests that between 235Ma and 15Ma therewas a period ofnon-sedimentation (Haileab and Brown 1994) The 20 m thick MioGoro Formation lies unconformably over the Gadeb Formation and isthe top of the Gadeb sedimentation sequence It is made up offluviatile sands sandstones and mudstones interbedded with claystuffs ash paleosols gravels and conglomerates which correspond tostreams flowing from the surrounding uplands that deposited allu-vial fans and gravel banks (Clark and Kurashina 1979b Williamset al 1979 Assefa et al 1982 Eberz et al 1988) This change fromlake to river depositional processes causedwidespread erosion of thelower lacustrine levels so that riverine deposits were banked againstolder lake sediments (Eberz et al 1988)

Despite intensive survey no archaeological traces were found inthe older lacustrine sediments of the Gadeb Formation (Clark andKurashina 1979b) and the entire archaeological sequence corre-sponds to the fluviatile deposits within the Mio Goro FormationApart from Gadeb 2A all archaeological sites at Gadeb postdate the145 Ma pumice but are older than 07 Ma on the basis of thereverse paleomagnetic polarity of the deposits (Clark andKurashina 1979a Williams et al 1979 Assefa et al 1982 Eberzet al 1988) This is confirmed by tephra correlations betweenGadeb and the Turkana Basin (Haileab and Brown 1994) sup-porting a 145e07 Ma time interval for the Gadeb archaeologicalsites (see also Brown 1994)

At the eastern end of the Gadeb plain both sides of the WebiGorge preserve up to 5 m thick gravel deposits where someabraded artefacts are found (Clark 1980) Nearer to the central andwestern parts of the plain the gravel deposits are thinner andspread within channels and exposures occur usually in themeanders of the Webi Shebele It is in these gravels and fine-grained fluvio-lacustrine sediments from the central part of the

Gadeb plain that Desmond Clark and colleagues (Clark andWilliams 1978 Clark and Kurashina 1979a Clark 1980 etc)concentrated their archaeological excavations

Clark discovered three main localities Gadeb 2 and Gadeb 8(Fig 1) each of them bearing several archaeological sites andGadeb 25 The latter is mentioned in some sources (Clark andKurashina 1979a Assefa et al 1982) but was never studied indetail or even mentioned in the most comprehensive analysis ofthe Gadeb assemblages (Kurashina1978) The Gadeb 2 and Gadeb 8localities share a similar fluvial depositional sequence which startswith basaltic gravels and feldspathic sands continues with alter-nating feldspathic and pumiceous layers and is capped withmassive pumice sediments (Williams et al 1979)

According to Clark andWilliams (1978) and Clark and Kurashina(1979a) the main cliff section at Gadeb 2 was 22 m high withdiatomites corresponding to the lake cycles in the lower part(Gadeb Formation) This is overlain with a marked erosional breakby the Mio Goro Formation with alternating fluvial gravels sandsand diatomaceous clays and capped by a sandstone level (see alsoAssefa et al 1982) Archaeological assemblages lie in shallowstream channels in the upper part of deposits There is howeversome uncertainty as to the number of sites present in Gadeb 2Clark and Williams (1978) listed three sites (Gadeb 2B Gadeb 2Cand Gadeb 2D) whereas Assefa et al (1982) mentioned four (Gadeb2A Gadeb 2B Gadeb 2C and Gadeb 2D) Other archaeologically-focused publications (Kurashina 1978 Clark and Kurashina 1979a1979b Clark 1980 etc) reported four sites (Gadeb 2A Gadeb 2BGadeb 2C and Gadeb 2E) but Gadeb 2D is not included This couldbe because only bones were originally documented at this site(Clark and Kurashina 1976) however some lithics were laterreported (Clark and Williams 1978) so Gadeb 2D might eventuallyhave been merged with another assemblage

The oldest assemblage in Locality 2 (and in the whole of theGadeb sequence) is Gadeb 2A embedded in the iron-stained base offerruginous gravels near the erosive contact with the GadebFormation diatomite (Fig 1) Assefa et al (1982) placed Gadeb 2Abeneath the pumice mudflow dated at 148 Ma The next oldest siteis Gadeb 2E located several hundred metres east of Gadeb 2A andcontained in a channel fill cutting into the 148 Ma pumice mudflow(Clark and Kurashina 1979a) The Gadeb 2E channel is described asone filled with alternating levels of silt fine sand and clays withlayers of cobbles rounded angular fragments and archaeologicalremains (Clark and Kurashina 1979a) The channel fill of Gadeb 2C ishigher in the sequence Here archaeological material lay on theweathered tuffs (see Fig 1) and was overlain by fine sands approx-imately 1 m thick Finally the Gadeb 2B site was stratigraphicallya little higher than Gadeb 2C but in the same basalt gravels

The Gadeb 8 outcrop is located onlyw1 km northeast of Gadeb 2(Fig1) Clark andWilliams (1978) distinguished twomain cut and fillstages in Locality 8 an earlier series of gravels and sands that dis-conformably overlie the diatomite and contains gt07 Ma old sitesand an upper part which corresponds to a later cycle with MiddleStone Age remains Desmond Clark excavated four Early Stone Agesites most of them probably younger than those at Locality 2(although see Assefa et al 1982) but still in reverse polarity sedi-ments (Clark and Kurashina 1979a) Three of those assemblages(Gadeb 8A 8D and 8E) are located in the same channel horizon andtherefore share a similar stratigraphic position characterized bygravels and sands resting on an unconformity eroding down thePliocene diatomites (Clark and Kurashina 1979a) These basalticgravels and feldspathic sands are capped by a palaeosol and thena thick layer of pumice sands The fourth assemblage in Locality 8 isGadeb 8F positioned 45 m above Gadeb 8E (Clark 1987) Gadeb 8Foverlies the palaeosol and is beneath the pumice sands (Williamset al 1979) and is the youngest Early Stone Age site in Gadeb


Site contexts

Table 1 summarizes contextual information and culturaladscription of the Gadeb 2 and Gadeb 8 sites according to theexcavators All of the Gadeb 2 sites (Gadeb 2A 2B 2C and 2E) andGadeb 8F were originally assigned to the Developed Oldowan B(sensu Leakey 1971) whereas Gadeb 8A 8D and 8E were classifiedas Acheulean (Kurashina 1978 Clark and Kurashina 1979a 1979b)This general classification was maintained in subsequent publica-tions (eg Clark 1980 Kurashina 1987 but see Assefa et al 1982)although the term Developed Oldowan C was eventually favouredfor Gadeb 2E and Gadeb 8F (Clark 1987)

All assemblages apart from Gadeb 8F (which lay on a paleosol)belong to stream channel deposits As mentioned above most of thesites were found in cobble and gravel layers indicating water actionover the assemblages However only Gadeb 2A and 8A wereconsidered sites in secondary position (see Table 1) based on theindex of artefact abrasion (Clark and Kurashina 1979a) Kurashina(1978) also noted that Gadeb 2B cannot be considered in primaryposition although the remaining Gadeb assemblages were stated tobe primarily in situ (Clark and Kurashina 1976 1979a Clark andWilliams 1978 Clark 1980 1987) Desmond Clark acknowledgedthat although there was some re-sorting of assemblages in generalthe artefacts were in fresh condition Therefore it was assumed thateven if the lightest elementshadbeen removedbywater action therewas no significant sorting and archaeological remains in Gadeb 2E2C 2B 8D 8E and Gadeb 8F were mainly unaltered (Clark 1987)

According to recounts by Kurashina (1978) and Clark andKurashina (1979a) Gadeb 8E was the largest assemblage fol-lowed by Gadeb 8A 2E 2C 2B 8D and Gadeb 8F In terms of artefactdensity Gadeb 8A exceeds 8E and the third largest concentration isGadeb 2C followed by Gadeb 2B 2E 8D and Gadeb 8F (see Table 1)Kurashina (1978) compared the density of 2309 lithics per squaremetre in Gadeb 8A with 34 in Gadeb 8F However this should beviewed with caution Clark and Kurashina (1979a) noted that thehandaxe concentration in Gadeb 8A is secondary (ie accumulatedby water) and the low density of artefacts in Gadeb 8F results fromthe merging in Table 1 of two excavation pits one of 8 5 m anda geological trench of 16 2 m (data from Clark 1987) As stated byClark and Kurashina (1979a) artefacts in Gadeb 8F were found ina discrete concentration spatially associated with a partial hippocarcass and therefore the density of artefacts was probably higherthan that shown in Table 1

Clark and Kurashina (1979a) mentioned the presence of faunalremains in Gadeb 2A 2B 2E 2C 8D 8E and 8F Although mostlyfragmentary several bovids hippo elephant zebra and pig werereported in Gadeb 2E and 8D and the hippo in Gadeb 8F (Clark andKurashina 1979a) The faunal remains were said to be associatedwith the artefacts but the fragmentary state of the bones and theirlow numbers prevented Clark and colleagues from interpretingfurther the juxtaposition of fossils and lithics The exception was

Table 1Site contexts of Gadeb assemblages according to the original excavators (Kurashina 197

Site Excavated surface (m2) Number of artefacts

Gadeb 2A 15 UnknownGadeb 2E 40 1741Gadeb 2C w5 622Gadeb 2B 8 589Gadeb 8A 8 1849Gadeb 8D 15 487Gadeb 8E 100 20276Gadeb 8F 72 385

Density of artefacts was calculated by dividing the numbers of artefacts by the area of thpresented specific figures which are reproduced in this table

Gadeb 8F which was considered to represent a butchering episodeof a hippopotamus by Developed Oldowan hominins (Clark andKurashina 1979a Clark 1987) This single-event activity area atGadeb 8F would contrast with the other localities in Gadeb whichwere said to represent ldquomulti-context multi-component concen-trations of high density most probably reflecting regular re-occu-pation over a longish period of timerdquo (Clark 1987 809) on thebanks and channels of shallow streams (Clark and Kurashina1979a)

Materials and methods

Apart from Gadeb 2A and Gadeb 25 for which only preliminarydata were presented (Clark and Kurashina 1979a Assefa et al1982) there is fairly detailed information on the Gadeb 2 andGadeb 8 lithic collections For example although no systematicdescription of all the Gadeb assemblages has ever been publishedKurashinarsquos (1978) PhD dissertation constitutes an invaluablesource for a comprehensive overview of the entire lithic collectionAdditionally Clark and Kurashina (19761979b Kurashina 1987)conducted statistical analyses of artefact typologies and providedvaluable information on site formation and artefact distribution(Clark and Kurashina 1979a Clark 1987) However technologicaldescriptions of lithics were uncommon in the 1970s and most ofwhat is currently known of the Gadeb assemblages corresponds totypological and metrical domains Building upon the work of Clarkand Kurashina (Kurashina 1978 Clark and Kurashina 1979a) thisreview seeks to follow methods of technological analysis to updateour knowledge of the Gadeb lithic collection

Between 2003 and 2009 several Gadeb assemblages wereanalysed in the National Museum of Ethiopia in Addis AbabaNearly all of the sites excavated by Desmond Clark were found inthe storage facility of the museum including Gadeb 2A 2E 2C 2B8A 8D 8E and 8F and a cursory inspection of all of the collectionswas conducted In the case of Gadeb 2A given that less thana dozen pieces were located and that artefact totals had neverbeen listed the resulting uncertainty about the character of thisassemblage ruled out a systematic analysis The other Gadeb 2sites (Gadeb 2E 2C and 2B) were selected for in-depth study aswell as Gadeb 8F and 8D This selection was made to acquirea comprehensive understanding of the so-called Developed Old-owan assemblages (Gadeb 2E 2C 2B and 8F) which could then becompared to the Acheulean sites (Gadeb 8D)

Table 2 compares Kurashinarsquos (1978) original figures withrecounts taken between 2003 and 2009 As can be seen in thistable the Gadeb 2B 2C and 8D collections are reasonably completebut a substantial fraction of Gadeb 8F and 2E could not be located inthe storage facility Much of the Gadeb collection is curated in smallfabric sacks and stored in solid trunks Many sacks were still sealedand sewn when the present review was conducted proving thatthey had not been opened since the original 1970s study so it is

8 Clark and Kurashina 1979a Clark 1987)

Artefactsm2 Context Original cultural adscription

Secondary Developed Oldowan435 Primary Developed Oldowan1244 Primary Developed Oldowan736 Altered Developed Oldowan2309 Secondary Acheulean325 Primary Acheulean2028 Primary Acheulean34 Primary Developed Oldowan

e excavated surface except for Gadeb 8A and Gadeb 8F for these Kurashina (1978)

Table 2Breakdown of lithic categories in the sites under study

Category Gadeb 2E Gadeb 2C Gadeb 2B Gadeb 8D Gadeb 8F

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Test cores e 129 e e 13 e 12 e e 8Cores 124 257 25 55 68 78 91 108 29 39HandaxesLCTs 3 7 3 9 4 3 38 31 6 11Smaller retouched pieces 17 78 8 38 61 22 37 17 34 28Percussive tools 122 110 1 1 1 e e 6 17 23Flakes 175 240 50 100 67 91 38 79 48 64Flake fragments 139 198 91 175 150 177 26 151 14 78Angular fragments 126 329 355 244 194 218 115 95 14 60Unmodified material 55 393 28 e 22 e 76 e 17 74

Total 761 1741 561 622 580 589 433 487 179 385

Categories listed follow general technological groups proposed by de la Torre and Mora (2005) and de la Torre et al (2008) Kurashinarsquos figures are adapted as followsKurashinarsquos modified cobbles correspond to test cores (sensu de la Torre and Mora 2005) choppers polyhedrons core scrapers and cores are listed here as cores handaxescleavers and proto-bifaces are listed as handaxes Kurashinarsquos flake scrapers modified flakes modified flake fragments are merged under the term smaller retouched piecessub-spheroids spheroids and battered cobbles are listed as percussive tools flake fragments are listed using the same terminology ie flake fragments Kurashinarsquos modifiedchunks utilized chunks chunks and cobble chunks are listed as angular fragments cobbles and split cobbles are listed as unmodified material


unlikely that some artefacts had been intentionally removed andstored elsewhere Therefore in the case of Gadeb 2E and 8F eitherall of the material listed by Kurashina (1978) was not collected andcurated in the museum or some trunks have yet to be found in thestorage facility

In order to assess the impact of the missing material on thisstudy Kurashinarsquos (1978) classification of lithics was adapted tomore recent proposals of technological categories (de la Torre andMora 2005 de la Torre et al 2008) Table 2 indicates thata substantial part of the missing lithics corresponds to clearlynatural (cobbles and split cobbles) or arguably natural material(test cores or modified cobbles in Kurashinarsquos terminology) This isthe case for a large part of themissing collection in Gadeb 2E and toa lesser extent in Gadeb 8F Therefore it is feasible that some of theunmodified cobbles had not been stored especially when takinginto account the fluvial contexts from which these assemblagesoriginated Whatever the case Table 2 indicates that the mostinformative parts of the Gadeb collections are still accessible Thepresent study reviewed a total of 2514 lithics from five sitescollectively weighing more than 380 kg and including about 330cores 54 large cutting tools and several hundreds of flakes andretouched pieces Such a collection allows for a detailed techno-logical analysis of the selected assemblages and constitutes thedataset of this work

Kurashinarsquos (1978) dissertation on the Gadeb assemblages fol-lowed the detailed type lists predominant in the 1970s popularizedby Leakey (1971) in the Olduvai sequence However nomenclaturein the present reanalysis follows more recent and syntheticapproaches to Early Stone Age assemblages (eg Isaac et al 1997)as updated by de la Torre and Mora (2005) Given the focus ontechnological features this study heavily relies on the use of dia-chritic schemes (Dauvois 1976) to reconstruct reduction sequencesof flakes cores and shaped artefacts

A preliminary study of raw materials was conducted by theoriginal analysts (Kurashina 1978 Clark and Kurashina 1979a)but no systematic attempt was made to petrologically charac-terize the Gadeb lithics The lithofacies characterization of theGadeb stratigraphic sequence (Assefa et al 1982) indicates thatthe gravel and conglomerates typical of the Mio Goro Formationconsisted mainly of clasts and pebbles of tuff pumice rhyolitetrachyte and basalt It can be assumed that most of the rawmaterials mainly trachytes and basalts used by Gadeb knappersderive from local river conglomerates Possible exceptionsinclude some handaxes made of ignimbrite from outcrops

situated 6 km to the south and west (Assefa et al 1982) and somechert and obsidian bifaces in Gadeb 8E the latter purportedlyobtained from a source 100 km away (Clark and Kurashina1979a) The only other pattern observed was the consistentlarger size of ignimbrite handaxes with respect to local lavaexamples (Clark and Kurashina 1979a) Therefore given the lackof more in-depth petrological results in this study all the lava rawmaterials are considered together and discussion will focus ontheir technological attributes

Cores are particularly informative in the assessment of knappingmethods and techniques and therefore detailed descriptions ofreduction systems are required de la Torre et al (2003) proposeda classification based on the consideration of cores as geometricvolumes with six ideal planes Flaking on these planes and theinteraction between them results in unifacial bifacial trifacial ormultifacial combinations The angle formed by the intersection oftheworked planes can be simple (lt45) or abrupt (gt45) Accordingto the directionality of flaking de la Torre et al (2003) distinguishedbetween unipolar bipolar and centripetal patterns However this isinaccurate knapping techniques include among others free-handthrowing and bipolar The latter may lead to confusion when someauthors indiscriminately use the term bipolar to refer both toa particular knapping technique and to the directionality of flakingHere it is proposed that the term bipolar must be reserved forknapping techniques involving a core resting on an anvil From thisperspective it is inaccurate to refer to unipolar or bipolar flakingdirectionality and it is more precise to distinguish between unidi-rectional or bidirectional flaking patterns Variability observed in theOlduvai assemblages also led to the differentiation betweencentripetal and peripheral flaking (de la Torre and Mora 2005) Thisdifferentiation is relevant as centripetal flaking entails themanagement of the central volume of surfaces whereas peripheralschemes only affect the edge of surfaces causing the loss of suitableknapping angles in the centre of volumes

It must be acknowledged that neither the original proposal ofknapping methods (de la Torre et al 2003) nor the extendedversion (de la Torre and Mora 2005) include the whole panoply ofknapping systems recognised in Early Stone Age assemblagesHowever variability of methods is such that a synthetic andreductive perspective must be adopted if intra and inter-assem-blage comparisons are to be made These schemes are based on thevariability observed in Peninj (de la Torre et al 2003) Olduvai(de la Torre and Mora 2005) and Gadeb (the present study) butcertainly do not claim to record all of the techno-typological

Figure 2 Idealized schemes of free-hand core reduction (expanded from de la Torreet al 2003 de la Torre and Mora 2005) USP Unifacial simple partial exploitationFlaking is unidirectional and restricted to one plane from a natural striking platformand the angle between the striking platform and the knapping surface is simple(lt45) Classic choppers fall into this category BSP Bifacial simple partial exploitationFlaking is unidirectional but in two adjacent surfaces separated by a simple-angledbifacial edge Chopping tools or bifacial choppers (Leakey 1971) fall into this categoryUAU1 Unidirectional abrupt unifacial exploitation on one knapping surface Flaking is


variability of ESA exploitation strategies Therefore schemes pre-sented in Fig 2 which update previous proposals (de la Torre et al2003 de la Torre and Mora 2005) must be considered as idealschemes of six surfaces with a number of simple or abrupt unifacialbifacial trifacial or multifacial surface interactions which at thesame time can show unidirectional bidirectional peripheral orcentripetal flaking patterns Based on these methodologicalpremises a technological analysis of the Gadeb assemblages ispresented in the following sections

The integrity of the Gadeb sites

Clark (eg Clark and Kurashina 1976 1979a Clark 1980 1987)asserted that most of the Gadeb assemblages were primarily in situeven if some minor re-sorting of the remains had occurredTherefore with the exception of Gadeb 2A and 8A (Clark andKurashina 1979a) not considered here and perhaps Gadeb 2B(Kurashina 1978) most sites were regarded as in primary positionThis was based primarily on low abrasion indices and absence ofpreferred orientation of artefacts Whereas the latter is difficult totest due to the lack of published quantitative information (we havesome data only for Gadeb 8A (Clark and Williams 1978) moredetailed statistics on abrasion are presented in SOM Fig 1 Gadeb 8Fand 2E show high percentages of fresh artefacts (684 and 625respectively) whereas non-abraded percentages in Gadeb 2C(89) 8D (44) and 2B (35) are minimal The highest ratios ofabraded and heavily abraded artefacts appear in Gadeb 2B (450and 97 respectively) Gadeb 2C (378 and 211) and Gadeb 8D(500 and 133) Gadeb 8F has only 90 of abraded artefacts and

unidirectional and limited to one surface and the angle between the striking platformand the knapping surface is abrupt (gt45) Many of Leakeyrsquos (1971) heavy-dutyscrapers fall into this category UAU2 Unidirectional abrupt unifacial exploitation ontwo independent knapping surfaces although there are two exploitation planes thereis no interaction between their respective striking platforms and knapping surfacesFlaking is unidirectional and the angle between the striking platform and the knap-ping surface is abrupt UAUT Unifacial abrupt unidirectional total exploitation There isonly one striking platform an abrupt angle of interaction between the striking andknapping surfaces and flaking takes place all over transversal and sagittal planes of thecore UABI Unifacial abrupt bidirectional exploitation Two opposed striking platformsare used to flake the same knapping surface but there is no exchange between thestriking and the knapping surfaces (hence unifacial) BAP bifacial abrupt partialexploitation Flaking takes place in two adjacent surfaces separated by an abrupt angleand the volume is exploited partially (ie some planes remain unworked) Some ofLeakeyrsquos (1971) heavy-duty scrapers fall into this category BALP bifacial alternatingpartial exploitation Two adjacent surfaces are partially knapped by means of alternateflaking using scars on the knapping surface of one plane as the striking platform forobtaining flakes on the other plane BALT bifacial alternating total exploitation Thewhole circumference of the core is exploited following the same bifacial alternatingstrategy as in the previous method UP Unifacial peripheral exploitation The hori-zontal plane is exploited unifacially through the rotation of the transversal and sagittalplanes but extractions do not meet in the centre of the volume and reduction islimited to the edge of the core BP bifacial peripheral Exploitation concentrates on thehorizontal plane but there are two interactive surfaces with the transversal andsagittal planes sometimes acting as preparation striking platforms for extractions onthe horizontal plane UC Unifacial centripetal exploitation The horizontal plane isexploited unifacially through the rotation of the transversal and sagittal planes andextractions are radial and usually meet towards the centre of the knapping surfacefacilitating the reduction of the volume BHC Bifacial hierarchical centripetal Anintersection plane divides the core into two asymmetrical and hierarchized volumesTransversal and saggital planes act as a subordinated volume (preparation surface) toobtain flakes in the main exploitation surface (see full discussion of this method and itsimplications in de la Torre 2009) Discoid this method widely known in the MiddlePalaeolithic literature (see Boeumlda 1993 Peresani 2003) is similar to the BHC exceptfor the unclear hierarchization of surfaces and the systematic alternating of strikes onthe bifacial edge Polyhedral cores with three or more knapping surfaces whichbecome spherical whether intentional (Texier and Roche 1995) or the unplannedresult of continued reduction sequences (Schick and Toth 1994) Multifacial coreswith three or more knapping surfaces which show no clear organization of flaking butthe irregular use of any available flaking angles


no heavily abraded pieces and both indices are equally low inGadeb 2E (57 and 24 respectively) Therefore the abrasionindex suggests greater disturbance than previously proposedparticularly in sites such as Gadeb 2B 2C and 8D where artefactsmay have been heavily affected by water

Artefact size curves (eg Schick 1984) are another usefulproxy to evaluate water disturbance However as Kurashina(1978) states that sediments from the Gadeb sites were notsieved the minute fraction of lithic assemblages is not availableIn fact not a single piece of debris was found in the presentreview and very few of the measured artefacts (n frac14 7 out of 2514)measured less than 20 mm Kurashina (1978) indicates thatsieving was unnecessary given the coarse size of deposits so itmay be assumed that minute pieces of debris simply were notthere to be recovered The question then is whether the lithics oflt20 mm indicative of in situ knapping activities were sortedaway by fluvial processes whereas larger artefacts remained inprimary position as Clark (eg Clark and Kurashina 1979a Clark1980 1987) suggested or whether the entire assemblages wererearranged and accumulated secondarily

Intra-assemblage category ratios can also aid in assessing theintegrity of collections Although tool-maker decisions do bias theratio of artefact categories preserved at sites extensive experi-mental work (eg Toth 1982 Schick 1984) demonstrates thatthere are expected proportions of flaked and detached pieces(sensu Isaac 1986) and that the latter usually outnumber coreforms at in situ assemblages (de la Torre and Mora 2005) SOMFig 1 illustrates this point and highlights the deficit of detachedpieces in Gadeb 8D and 8F Although this paucity is more apparentin Gadeb 8D and 8F it can also be extrapolated to other assem-blages For example the flake core ratio (considered here as thesum of flakes and flake fragments divided by the number of cores)yields a ratio of only 24 flakes per core in Gadeb 2E and 26 flakesper core in Gadeb 2B while recounts of the number of scars oncores show that cores were considerably more reduced (seebelow) Therefore it can be stated that in general Gadebassemblages contain substantially less detached materials thanshould be expected

Finally site contexts and other remains purportedly associatedwith stone toolsmust be consideredwhen discussing the integrity ofthe Gadeb lithic assemblages For example questions arise about therelationship between the unmodified lithics and knapped artefactsAccording to Kurashinarsquos (1978) recounts (see Table 2) unmodifiedblocks outnumbered all (Gadeb 2E) or nearly all (Gadeb 8F) otherlithic categories in some assemblages Due to the storage proceduresmentioned above it is likely that figures for unmodified material inthis paper are underrepresented with respect to the original esti-mates Despite this Table 3 shows that unmodified lithics in the formof complete and fragmented blocks and cobbles still representa significant part of the Gadeb collections especially in assemblages

Table 3Breakdown of categories by weight (grams)

Category Gadeb 2E Gadeb 2C

Test cores e e

Cores 56615 10880HandaxesLCTs 4385 2274Smaller retouched pieces 901 481Percussive tools 81566 260Flakes 12594 1508Flake fragments 6640 1563Angular fragments 10269 6296Unmodified blocks 29923 9183

Total 202893 (162701) 32445 (16966)

In parenthesis total weight per site excluding unmodified blocks and angular fragments

like Gadeb 2E 2C and 8F where dozens of kilograms correspond tonatural rocks Taking into consideration the fluvial environment inwhich these sites are located and the conglomerate character of thispart of the sequence (Assefa et al 1982) it is difficult to consideras archaeological in origin the unmodified rocks which oftenoutnumber the knappedpounded artefacts especially inhighenergycontexts where natural cobbles are common

Questions about site integrity also arise with regards to thecontextual links between lithics and bones As mentioned aboveClark and Kurashina (1979a) were prudent when assessing possiblecontextual relationships between the lithic assemblages and fossilsdue to the poor preservation and fragmentary nature of the bonesThey proposed Gadeb 8F as the only clear evidence for an associ-ation between fossils and lithics and considered the assemblage asa hippo butchery site (Clark and Kurashina1979a Clark1987) Thiswas based on the presence of several hippo bones (according toKurashina (1978) three tusks one left scapula and one rib) thatcould correspond to a partial skeleton and on the spatial associa-tion with the lithics as the ldquoscapula long bone and rib fragmentslay together with two sub-spheroids and a spheroid which hadbeen used to break up the bones to get at the marrowrdquo (Assefa et al1982 42) Nevertheless we must bear in mind that Kurashina(1978) only reported 20 bone remains (the aforementioned hippobones as well as a bovid tooth and another of Equus) Also althoughGadeb 8F is the only site of the sequence deposited in a low energyenvironment (a paleosol) and with lithics mostly showing freshedges (see SOM Fig 1) smaller stone tool categories are clearlyunderrepresented (Table 2) suggesting that even this assemblageexperienced some winnowing This pattern together with thefragmentary and weathered character of the preserved bones (persobs) precludes a conclusive account for Gadeb 8F and in this casetoo might question the putative association between the stone andbone assemblage

There are several lines of evidence suggesting that the integ-rity of Gadeb assemblages has been seriously affected by naturalprocesses A reconsideration of abrasion indices (SOM Fig 1)indicates that except for Gadeb 8F and to a lesser extent Gadeb 2Eall of the studied assemblages contain significant numbers ofabradedmaterial Artefact size patterns (Table 4) also clearly showthe absence of small fraction lithics in all sites and category ratios(SOM Fig 1) indicate fragmentation of the chaicircne opeacuteratoire andoverrepresentation of large artefacts Added to the coarse matrixof deposits (eg Assefa et al 1982) and the probable spuriousrelationship between artefacts unmodified rocks and fragmentedfossils it becomes clear that most if not all of the Gadebassemblages are the result of fluvial dynamics that have mixedelements with different depositional histories Despite this theGadeb assemblages correspond to stratigraphically-controlledcontexts which allow the systematic technological appraisalpresented below

Gadeb 2B Gadeb 8D Gadeb 8F

1661 2199 e

9107 15926 121901841 20414 24382231 2345 2748141 e 151292590 2533 23244264 1387 8998357 6817 13603027 11008 12282

33219 (21835) 62629 (44804) 49370 (35728)

Table 4Size (mm) and weight (grams) of the main lithic categories in the Gadeb assemblages

Gadeb 2E Gadeb 2C Gadeb 2B Gadeb 8D Gadeb 8F

Mean Std D Mean Std D Mean Std D Mean Std D Mean Std D

Flakes Length 481 279 417 201 448 149 542 186 518 159Width 453 275 378 181 400 143 497 205 488 172Thickness 165 126 134 69 154 61 178 85 149 61Weight 720 1908 302 547 386 530 666 777 484 384

Cores Length 812 258 786 242 563 178 647 185 783 233Width 698 255 687 226 463 146 525 148 664 227Thickness 530 218 527 246 336 138 358 107 512 199Weight 4603 4845 4352 4353 1339 1419 1769 1461 4203 3971

LCTs Length 1523 862 1387 476 1273 220 1510 278 1093 410Width 1090 515 900 156 860 142 837 172 718 178Thickness 550 223 537 198 395 93 387 92 357 108Weight 14617 18240 7580 5027 4604 2429 5372 2406 4063 3859

Small retouch Length 522 199 546 169 463 152 573 184 605 165Width 412 197 444 273 381 131 422 104 552 205Thickness 181 84 168 73 144 46 176 58 198 62Weight 530 653 601 724 365 318 669 642 808 556


Results

The Gadeb 2E assemblage

The lithic collection of Gadeb 2E studied at the National Museumof Ethiopia consists of 761 lithics (see Table 2) 72 (n frac14 55) areunmodified cobblesblocks which alongside angular fragments(166 n frac14 126) were removed from further analysis due to theirprobable natural origin The resulting percentages (Fig 3) indicatethe predominance of detached pieces (flakes flake fragments andsmall retouched pieces) against flakedpounded artefacts (cores andpercussive tools) This preponderance refers only to the number ofitems but the overall weight of each category (Table 3) demonstratesthat cores and percussive tools are substantially more relevant atleast in terms of raw material expenditure In fact even whenconsidering only frequencies of items there is an imbalance betweenflakedpounded artefacts and detached elements The flakecoreratio (24) is proportionally low particularly when taking intoaccount that Gadeb 2E cores have an average of 87 flake scars percore Thus there is an acute shortage of some artefacts in theassemblage especially of the smallest fraction and the debitagewhich must be attributed to taphonomic causes

Although the average flake size is nearly 5 cm (Table 4) there aretwo neatly different chaicircnes opeacuteratoireswithin theflake populationone related to the flaking of small debitage (SOM Fig 2) and theother to the production of large cutting tools (SOM Fig 3) Fig 4Ashows that alongside flakes of lt6 cm (866 of the sample) thereare several larger ones (nfrac14 38 someweighing over a kilogram) thatcould have served as blanks for the production of large cutting tools(LCTs) Therefore even if most flakes are patterned within the 4 to6 cm lengthmodule typical of small debitage systems Gadeb 2E alsocontains flakes that belong to a different chaicircne opeacuteratoire that ofLCT production whose attribution would remain undetectable ifonly size means were presented

525 of the flakes display no cortex on the dorsal and platformsurfaces (Fig 4C) and have an average of 289 previous scars higherthan in any other site in Gadeb (see also Fig 4D) Although strikingplatforms are rarely prepared (only 38 of butts are bifaceted andnone are multifaceted) most flakes (873) were struck fromdecorticated platforms which indicate bifacial rotation of cores(Fig 4B) Dorsal scar patterns of flakes support this observationSOM Fig 4 shows that bifacial interchange of core surfaces wasaccompanied by extensive rotation of each surface Althoughcentripetal flakes are not the most abundant they coexist in Gadeb

2E with unidirectional and predominantly cortical products typicalof more static flaking methods (Fig 5)

The number of cores in Gadeb 2E (n frac14 124) is remarkably highforming 214 of the items in Fig 3 Whereas some of the flakes arerolled the cores are generally in fresh condition suggesting that thiscomponent of the assemblage was not sorted or dragged fromupstream occupations There is great size variability (Table 3 andFig 6A) ranging from tiny cores of less than 4 cm to those larger than15 cm in length and weighing over 2 kg However despite this sizevariability (Fig 7 and SOM Fig 5) the Gadeb 2E cores all belong tothe small debitage chaicircne opeacuteratoire Even the largest cores availablein the collectionwere not big enough to produce the large LCT blankspresent at the site which were likely transported from elsewhere

Most of the cores seem to have been made from cobblesimmediately available in the local streams and they usuallypreserve large cortical surfaces (Fig 6C and D) However there is noclear pattern in reduction intensity Given the local availability ofraw material it might be expected that most cores were littlereduced (see examples from SOM Fig 6) However that is not thecase Fig 6B shows that a substantial part (619) of the Gadeb 2Ecores have more than 6 flake scars the majority of those with morethan 10 negatives Here the number of core scars can tentatively beused as a proxy to address reduction intensity which if consideredwith the size variability mentioned above produces an inconclu-sive pattern one in which large-sized local lava cobbles weresometimes abandoned after a few removals whereas others wereheavily reduced and difficult to manipulate small cores (SOM Fig 7)that were discarded following longer reduction process

Thus in Gadeb 2E there is coexistence between minimallyreduced cores (which preserve most of the original cortex weighup to 2 kg and have only a few extractions and intensivelyexploited cores whose reduced cortical surfaces) minimal size andhigh scar numbers indicate long knapping processes to a stagewhere flaking was hardly viable Some of the cases in SOM Fig 7and Fig 8 illustrate this point as they show how difficult itwould be in terms of handling mechanics to continue knapping

The study of knapping methods also yields interesting resultsBifacial systems (BSP BALP BALT BP BHC and DISC) account for551 of cores demonstrating frequent exchange of knappingsurfaces as opposed to strategies based on exploitation of singlesurfaces Fig 9 indicates that the interaction of surfaces was com-plemented with frequent rotation of volumes Thus radialmanagement of surfaces (UP BP BHC DISC) is observed in 339 ofcores (see also Table 5) Many radial cores correspond to methods

Figure 3 Percentages of main lithic groups in the Gadeb assemblages (see absolute frequencies in Table 2) Angular fragments and unmodified blocks are excluded


where core volumes are not fully managed (UP and BP n frac14 25) butthere are also examples of well-structured exploitation sequences(BHC and DISC n frac14 12)

Bifacial hierarchical centripetal methods appear in severalstages of reduction from large cores abandoned in the earlyphases of exploitation to very small cores that seem to haveundergone long reduction processes (Fig 10) Application of these

methods allow the knapper to obtain several flaking sets by thecontinuing rejuvenation of surfaces and volumes (Boeumlda 1994Lenoir and Turq 1995 Peresani 2003 de la Torre 2009) andtherefore to extend substantially the utility of cores It could thenbe stated that these cores represent the existence of fixed mentaltemplates that led knappers to apply some particular flakingmethods regardless of blank size until cores were intensively

Figure 4 Flake attributes in the Gadeb assemblages A) Flake size ranges in millimetres B) Striking platform types on flakes C) Percentage of cortex on flakes according to Tothrsquos(1982) types D) Number of scars on dorsal sides of flakes


exhausted Nevertheless the utility of small flakes such as thosedetached from some of the cores shown in Figs 8 and 10 remainsunclear

Despite the long use life of some Gadeb 2E cores it must alsobe recognised that most cores show shorter reduction sequencesand rather unstructured knapping methods Thus many cores areremarkably expedient where cortical surfaces or natural fractureplanes are normally used as knapping platforms and there islimited rotation of volume (SOM Figs 6 8 and 9) The abruptangle formed by the interaction between knapping and strikingsurfaces hinders the attainment of long production sets so thatcores had to be abandoned after a few flake removals due to theloss of suitable angles Therefore the coexistence of structuredand expedient reduction methods is an important element ofthe small debitage chaicircne opeacuteratoire in Gadeb 2E and should beconsidered when evaluating overall characteristics of theassemblage

Questions arise when analysing retouched lithics given thepost-depositional processes that affected all of the Gadeb assem-blages and which could cause pseudo-retouch on the edge of

pieces Although this paper has adopted a conservative approach tothe analysis of retouch retouched lithics are unambiguouslypresent in all the sites studied Thus although the percentage islow especially when compared to nearby sites like Gadeb 2B (seeFig 3) the small debitage chaicircne opeacuteratoire at Gadeb 2E includessome retouched pieces (n frac14 17) Retouch is unsystematic usuallydenticulated unifacial and does not seem to follow standardizedshapes (Fig 11) In general small retouched pieces can be classifiedas sidescrapers and denticulates but they are rare in the assem-blage and do not seem to have been the main objective of knappingactivities in Gadeb 2E

Alongside these diminutive (approximately 4e5 cm) retouchedpieces there are several other tools in Gadeb 2E that are smallenough to have been struck from cores corresponding to the smalldebitage chaicircne opeacuteratoire but which show traits that resemble theshaped tools typical of the LCT operational sequence Thusretouched pieces from Fig 12 are larger (w6-10 cm) and above allseem to represent the aim of producing pointed shapes sometimesthrough bifacial and bilateral retouch which could in someinstances (eg Fig 12 2 and 3) be considered as handaxes

Figure 5 Examples of small debitage products attributed to unidirectional and radial systems in Gadeb 2E


Although a continuum can be traced in the size ranges ofretouched tools in Gadeb 2E there is also a break between the smalldebitage chaicircne opeacuteratoire and that of LCTs As mentioned abovethere are no LCTcores in the assemblage Also lacking aremost of theproducts (large flake fragments and chunks etc) that would beexpected should the production of LCTs have taken place on siteNevertheless some large flakes (gt10 cm) demonstrate that LCTtechnology occurred in Gadeb 2E Considering Clark and Kurashinarsquos(1979a) estimation that the nearest ignimbrite source is 6 km awaythen piece number 1 in Fig 13 shows that hominins flaked andtransportedmassive blanks (either retouched or unformatted) to thesite from distant locations More importantly these examples indi-cate that different flaking techniques were known to Gadeb 2Eknappers The production of the flakes and LCTs in Fig 13 could haverequired the use of dormant percussors or static boulder cores asopposed to the free-hand flakingmethods used in the small debitagechaicircne opeacuteratoire

Finally the relevance of percussive activities in Gadeb 2E mustbe stressed Kurashina (1978) mentioned the presence of abun-dant battered cobbles as well as sub-spheroids and spheroidsThis reanalysis has confirmed that battered tools (n frac14 122) makeup a substantial part of the assemblage about 21 of the pieces ifunmodified cobbles and angular fragments are excluded (Fig 3)

In fact the total weight of battered artefacts (w81 kg) is thehighest of the assemblage (Table 3) and confirms that percussiveactivities were a relevant activity at Gadeb 2E The most abundantpercussive artefacts are hammerstones with fracture angles(sensuMora and de la Torre 2005) These tools (nfrac14 56) account to459 of battered artefacts and outnumber regular flaking ham-merstones (426) and anvils (115) In Gadeb 2E some ham-merstones with fracture angles show extremely heavily batteredridges and could be related to activities other than knapping asargued elsewhere (de la Torre and Mora 2005) Unfortunatelythe poor resolution of the archaeological context makes it difficultto assess the relationship of battered tools with other elements ofthe assemblage and further discuss the functional meaning ofthese artefacts

The Gadeb 2C assemblage

This study reviewed 561 lithics in Gadeb 2C a figure close toKurashinarsquos (1978) original recount (n frac14 622) However thebreakdown of categories (Table 2) diverge substantially as many ofthe lithics originally classified as flakes cores and others are hereconsidered as pieces with natural fractures It is important to recallthe large degree of disturbance at this site Most of the material

Figure 6 Core attributes in the Gadeb assemblages A) Core size ranges in millimetres B) Number of flake scars on cores (scars per core averages Gadeb 2E frac14 87 Gadeb 2C frac14 70Gadeb 2B frac14 54 Gadeb 8D frac14 54 Gadeb 8F frac14 91) C) Percentages of cortex D) Original core blank


(589) is abraded or severely abraded and only 89 shows noabrasion (SOM Fig 1) This high degree of abrasion alongside thecoarse sedimentary context and absence of small lithics indicatesconsiderable energetic water flows that mixed archaeological andnaturally fractured items

Once ambiguously archaeological (angular fragments) andclearly natural material (unmodified blocks) are excluded from theanalysis the Gadeb 2C collection is substantially reduced to only178 artefacts (Fig 3) Flakes (281) and flake fragments (511)predominate although there is proportional deficit of debitage Theflakecore ratio is 56 hence higher than in Gadeb 2E but still lowerthan expected In fact as there is an average of seven scars per corein Gadeb 2C the number of flakes found at the site should havebeen substantially higher further reinforcing the notion of distur-bance and winnowing of the assemblage

The flakes average approximately 4 cm in length (Table 4) mostclustering in the 2 to 4 cm size range with only a few showinglarger size patterns (Fig 4A) Thus nearly all flakes can be assignedto the small debitage chaicircne opeacuteratoire Flake striking platforms aremostly unifaceted (872) with only marginal presence of bifacetedor cortical butts (Fig 4B) In contrast with other assemblages Gadeb2C flakes show low percentages of cortex (Fig 4C) 681 of theflakes have no cortex whereas completely cortical products arealmost non-existent (n frac14 1 21) Equally Gadeb 2C flakes showhigher percentages of dorsal surface scars (3e4 scars) than in otherassemblages (Fig 4D) which also suggest more intense reductionsequences Direction of flaking deduced from the scars on flakesindicates predominantly unidirectional knapping methods inwhich there was little rotation of flaking surfaces (SOM Fig 10)

Data derived from the cores (n frac14 25) only partially supportspatterns shown by the flakes For example all cores show somecortex whereas indices of non-cortical flakes in Gadeb 2C are

particularly high Gadeb 2C cores are primarily made on cobbles(Fig 6D) have a mean length of nearly 8 cm (Table 4) and showlower scar averages than Gadeb 2E (Fig 6B) The predominance ofcortical surfaces and low scar indices indicate short reductionsequences in which local cobbles of lt10 cm length and w500 g(Table 4) were selected as cores and abandoned after a few flakeshad been removed

The reduction methods in Gadeb 2C are consistent with thequantitative parameters outlined above Fig 9 and Table 5 showthat unifacial systems (USP UAU1 UAU2 UAUT UP) predominateover bifacial methods (BSP BAP BALT BP) None of these methodsare very effective in the execution of long reduction sequences asmaintenance of suitable angles becomes difficult due to inefficientmanagement of volume In general the Gadeb 2C cores indicatelittle rotation of knapping surfaces which supports flake scarpatterns Both flakes (SOM Fig 10) and cores (SOM Fig 11) indicateunidirectional exploitation systems in which once the knappingangles become too obtuse the cores are discarded rather thanrejuvenated through a change of flaking surface or rotation of thesame surface In those cases where interaction of flaking surfacesoccurs there is either little rotation of cores (eg BSP BAP) or thecentral volume of flaking surfaces is not exploited (BALT BP) It canthus be stated that the small core and flake technology in Gadeb 2C(Fig 14) shows rather expedient exploitation methods wherereduction sequences are usually short cores are poorly structuredand abandoned after the production of a few flakes

Small retouched artefacts are scarce in Gadeb 2C (n frac14 8)although percentage-wise they are more abundant than in Gadeb2E They are all denticulates on flakes and flake fragments withunsystematic modification of edges and absence of standardizedforms Many of the pieces originally classified as shaped tools(Kurashina 1978) exhibit pseudo-retouch and it cannot be ruled

Figure 7 Examples of core size variability in Gadeb 2E


out that the percentage of naturally denticulated pieces was evenhigher although difficult to ascertain due to the general abradedstate of the assemblage Pieces 4 and 5 in Fig 14 are typicalexamples of this pattern with w5 cm flake blanks deemed asretouched in which edges were marginally modified formingnotches and denticulates

Some pieces such as Fig 14 6 do not entirely fit within thesmall debitage chaicircne opeacuteratoire for the retouch is on larger flakeblanks However these are morphologically similar to the smallretouched tools in which denticulated edge modification is irreg-ular and does not seem to impose any particular shape As is thecase for Gadeb 2E the intermediate retouched pieces in Gadeb 2Cprobably relate to the LTC chaicircne opeacuteratoire In the Gadeb 2Cassemblage the LCT reduction sequence is only clearly representedby three pieces but they are indisputably evidence of large flakeproduction and handaxe shaping Fig 15 illustrates two of theseexamples Neither show successful management of the centralvolume with simple angled rather than plain retouch making it

difficult to overcome step and hinge fractures NeverthelessFig 151 displays a clear aim to work the two surfaces througha bifacial edge in order to obtain a roughly balanced symmetricalprofile On the other hand Fig 152 is a w13 kg flake obtained bythe splitting of a large core and which was subsequently retouchedunifacially on both edges in order to get a trihedral point Hencethese pieces prove the presence in Gadeb 2C of LCT elementsalongside the more common items associated with the small deb-itage chaicircne opeacuteratoire

The Gadeb 2B assemblage

The Gadeb 2B assemblage reviewed in this paper consists of 580pieces a figure almost identical to Kurashinarsquos (1978) originalnumber (n frac14 589) The breakdown of categories (Table 2) is alsosimilar to Kurashinarsquos although there is divergence in the totals ofsmall retouched pieces which are higher in this review Abrasionindices (SOM Fig 1) indicate that nearly all of the assemblage

Figure 8 Bifacial hierarchical centripetal (1e4 6) and discoid (5) cores at Gadeb 2E


(965) shows some rounding with 547 of pieces being abradedor very abraded Therefore it is clear that sorting occurred and thatthe breakdown of categories does not reflect the original compo-sition of the assemblage Nevertheless after removing angularfragments and natural blocks from the analysis there still remainsa fairly large collection (nfrac14 364 artefacts) including a high numberof cores and retouched pieces that provide relevant technologicaldata

With an average length of approximately 5 cm (Table 4) mostflakes belong to the small debitage chaicircne opeacuteratoire Howeverthere are several larger flakes (some greater than 10 cm and 400 g)which certainly do not correspond to the small core and flakereduction sequence but rather to that of LCTs Flake striking plat-forms are usually unifaceted (619) although cortical butts (206)are also relatively abundant However the percentage of dihedralstriking platforms (127) in Gadeb 2B is the highest of all Gadebassemblages and this is also the only site where multifaceted buttswere reported (see Fig 4B) Most flakes (456) show no cortexwhereas only 35 are completely cortical On the other hand themean scar count on the flakes (227) is lower than in otherassemblages such as Gadeb 2E and 2C while only a few flakes(291) display more than two previous scars on their dorsal faces(Fig 4D) The direction of previous negative scars on the flakes(Fig 16) indicates unidirectional methods and rare rotation ofknapping surfaces Despite this pattern the percentage of edge-core flakes (134 of the whole flake sample) is fairly high whichimplies rotation of knapping surfaces (SOM Fig 12) Nonethelessthese edge-core flakes seem to be the result more of a search fornew angles rather than rejuvenation pieces from the rearrange-ment of flaking and striking surfaces

The entire core sample in Gadeb 2B can be attributed to thesmall debitage chaicircne opeacuteratoire The average core length is 56 cmsmaller than in any other Gadeb site (Table 4) In fact nearly half ofthe cores (448) are under 5 cm and only one (15) is larger than10 cm (Fig 6A) This size pattern may also explain the low core scarindex (meanfrac14 544 negatives per core) the lowest alongside Gadeb8D (see also Fig 6B) Most cores (842) retain cortex and 316 arepredominantly cortical (Fig 6C) so small core size can be explainedby selection of small cobbles (Fig 6D) rather than by intensivereduction processes of larger blanks On the other hand in Gadeb2B several cores aremade on flakes (nfrac14 four 63) which is rare inother assemblages and also contributes towards the generallyreduced dimensions of cores at the site

Despite the small blank size Gadeb 2B knappers frequentlyconducted bifacial reduction of cores which also included rotationof flaking surfaces (Fig 17) Fig 9 and Table 5 show that interactionof two debitage planes (BSP BAP BALT BP) occurred in 578 ofcores and that full rotation of flaking surfaces (BALT UP BP) wasalso relatively frequent (281) Nevertheless despite the precisionrequired to obtain flakes from such tiny blanks (see Fig 17)knapping methods in Gadeb 2B are rather simple or unstructuredFor instance 125 of the cores show no maintenance of stableknapping and exploitation surfaces (multifacial cores) and thereare no examples where the central volume was successfullymanaged (ie discoid and BHC methods) In general only theperipheral volume close to the core edge was reduced leading torapid loss of suitable angles This edge was dealt with throughabrupt and simple angled flaking and also through alternation offlaking and striking surfaces In fact consecutive exchange ofplatforms (BALP and BALT) is particularly common in Gadeb 2Bespecially among the smallest cores (Fig 17)

Many of the small retouched pieces have fresh edges so it isunlikely that retouch was produced by post-depositional processessuch as trampling If the intentional retouching of these pieces isaccepted then Gadeb 2B yields the largest percent of smallretouched artefacts of the five sites studied As shown in Table 2 andFig 3 the number of small retouched pieces is almost equal to thatof flakes making up a significant percentage (168) of theassemblage With an average length of 46 cm (see Table 4) theseretouched pieces are significantly smaller than in the other Gadebassemblages and are generally more carefully shaped

The high number of small retouched flakes (n frac14 61) in Gadeb2B permits a closer examination of their main characteristics Forexample there is clear preference for the choice of whole flakes(607) versus flake fragments (377) or small pebbles (16)as blanks to be retouched However given the similar metricsbetween flakes (mean length frac14 448 mm mean weight frac14 386 g)and small retouched pieces (mean length frac14 463 mm meanweight frac14 365 g) the intentional selection of blanks according tosize for retouch cannot be stated categorically Typologically theGadeb 2B small retouched pieces are not unlike those in otherassemblages most being notches and denticulated sidescrapers(Fig 18) However retouch is often less marginal and morecontinuous along the edges of pieces In fact a few pieces showretouch which shapes a tip (eg Fig 18 1 5 amp 7) and thereforemay be indicative of a pattern to produce pointed forms

Figure 9 Knapping methods employed in the Gadeb cores according to the ideal schemas proposed in Fig 2


Finally Gadeb 2B shows elements typical of the LCT chaicircneopeacuteratoire This reduction sequence is represented by some largeunretouched flakes and also shaped LCTs (Fig 19) Althoughnumerically these LCTs are not abundant (n frac14 4) they provide

valuable data on the knapping strategies involving flaking andshaping large forms Fig 19 2 3 and 4 shows that large cores wereprepared to produce heavy-duty flakes which in some instanceswere also shaped However Fig 19 1 shows that cobbles were also

Table 5Absolute and relative frequencies of knapping methods in the Gadeb cores

Method Gadeb 2E Gadeb 2C Gadeb 2B Gadeb 8D Gadeb 8F

N N N N N

USP 4 37 1 42 2 31 9 113 2 91BSP 5 46 5 208 6 94 9 113 2 91UAU1 21 193 5 208 1 16 12 15 6 273UAU2 9 83 1 42 7 109 1 13 4 182UAUT 3 28 1 42 0 0 1 13 0 0BAP 18 165 1 42 7 109 16 20 0 0BALP 3 28 0 0 11 172 8 10 2 91BALT 3 28 1 42 3 47 4 5 1 45UP 6 55 3 125 5 78 2 25 3 136BP 19 174 2 83 10 156 14 175 0 0BHC 10 92 0 0 0 0 1 13 0 0DISC 2 18 0 0 0 0 0 0 0 0POLIH 0 0 1 42 0 0 0 0 1 45MULTI 6 55 3 125 8 125 3 38 1 45

Total 109 100 24 100 60 937a 80 100 22 100

Knapping methods as described in Fig 2a Four cores made on flakes in Gadeb 2B are not included


used as LCT blanks Fig 19 5 could represent either a shapedcobble or (most likely) a split cobble that was shaped into a pointperhaps similar to that seen in Gadeb 2C (Fig 152) Except for thecleaver (Fig 19 3) the aim of all of the Gadeb 2B LCTs seemsdirected at obtaining a pointed end This is probably the onlytypological pattern shared by all pieces which lack any otherstandardized pattern None of the LCTs shows bifacial reductionand certainly no symmetrical shaping of volume Retouch does notpenetrate the blank volume and is restricted to the edges which areonly marginally modified Although all of these pieces are attrib-uted to the LCT chaicircne opeacuteratoire none qualifies as a biface

The Gadeb 8D assemblage

The Gadeb 8D collection discussed in this paper (n frac14 433) issimilar to Kurashinarsquos (1978) original recounts (n frac14 487) so theassemblage stored at the museum seems to have been preservedfairly complete (Table 2) Most pieces classified here as angularfragments have rolled edges and are likely to belong to the originalsedimentary matrix Once these angular fragments and unmodifiedblocks are discounted (Fig 3) there remains a high percentage ofrounded pieces (SOM Fig 1A) with 633 of artefacts being abradedor heavily abraded Winnowing of the assemblage is especiallyconspicuous when the percentage of detached elements is exam-ined As shown in SOM Fig 1B debitage is heavily underrepre-sented in Gadeb 8D Table 2 illustrates that the sum of flakes andflake fragment is still lower than the total number of cores If thenumber of scars on cores (with an average of 54 extractions percore a minimum of 491 flakes is expected) and handaxes (mean of48 scars per piece with an expected minimum of 182 flakes) istaken into account under representation of debitage becomes evenmore acute Therefore the sample bias at Gadeb 8D is significantand must be taken into account when considering links betweendifferent elements of the assemblage

The technological interpretation of regular flakes is complicatednotonlybecauseof limitednumbers Although themean sizeofflakes(approximately 5 cm) might indicate the small debitage chaicircneopeacuteratoire (Table 4) the fact is that many flakes are larger thanmostof the cores present at Gadeb 8D Therefore it is possible that manyregular flakes belong to LCT preparation or handaxe roughing outStriking platform preparation is absent (Fig 4B) and platforms arepredominantly cortical (657) In fact 971 of flakes preserve cortexeither on the dorsal side andor butt and 229 are completely

cortical (Fig 4C) Very few flakes display more than a couple ofprevious removals and none more than four scars (Fig 4D) Thedirection of previous removals (Fig16) suggests either unidirectionalmethods or flaking that may convey rotation of surfaces but nointeraction between scars eg as happens in methods where thecentral volume is not exploited The amount of cortex paucity ofdorsal scars and unidirectional patterns of unmodified flakes inGadeb 8D (SOM Fig13) therefore demonstrate non-intensive flakingof knapping surfaces and short reduction sequences be they relatedto exploitation of either cores or handaxes

The small debitage chaicircne opeacuteratoire iswell represented inGadeb8D by a high number of cores (n frac14 91) Furthermore given theconsiderable number of test cores (ie blocks or cobbles with one totwoscarswhichare consideredas rawmaterial testing) anargumentcould be made for the on site knapping of small cores but productsare underrepresented due to winnowing of the assemblage Alongwith the cores from Gadeb 2B those in Gadeb 8D are the smallest ofall sites studied (mean frac14 647 mm) so they clearly correspond toa chaicircne opeacuteratoire that is different from that of LCTs The small coresize is unlikely to be due to intensive blank reduction Very few coresare non-cortical (Fig 6C) and indeed Gadeb 8D cores have the lowestaverage scar count (543 negatives per core) matched only by Gadeb2B (meanfrac14 544) In sum Gadeb 8D cores are usually made on smallcobbles (Fig 6D) that were used to remove a short series of flakesafter which they were rapidly discarded

The reduction methods in Gadeb 8D include a panoply of uni-facial (USP UAU1 UAU2 UAUT UP) and bifacial (BSP BAP BALPBALT BP) systems (see Table 5 and Fig 9) Methods including thefull rotation of exploitation surfaces (BALP BALT UP BP BHC) arerelatively abundant (363) although central volumes are usuallypoorly exploited Therefore the small cobble size and poormanagement of the central volume led to rapid loss of suitableangles even among radial cores (Fig 20) Nevertheless exhaustionof appropriate angles may not explain the low intensity of corereduction For example many cores in SOM Fig 14 still maintainoptimal volumes that could be exploited without rotation rejuve-nation or surface exchange They simply were abandoned aftera few detachments well before the suitable angles were lost

Small retouched pieces (n frac14 37 and 153 Fig 3) are almost asabundant as whole flakes (n frac14 38 157) reaching a percentagesimilar to that described above for Gadeb 2B But whereas in thelatter there was a preference for whole flakes as blanks for smallretouched tools in Gadeb 8D 459 of retouched pieces were on

Figure 10 Bifacial hierarchical centripetal cores in different stages of reduction in Gadeb 2E


flake fragments followed by flake blanks (351) and small pebbles(109) with 81 of pieces on undeterminable blank types Smallretouched tool size (mean length frac14 573 mm) is very similar to thatof flakes and flake fragments (mean length frac14 541 mm and529 mm respectively) so it is unclear whether there was prefer-ential selection of blanks according to size It should also beremembered that the average length (w55 cm) of both flakes andsmall retouched pieces is almost identical to that of cores (seeTable 4) so it may be that they correspond to different reductionsequences As in all sites previously described the small retouchedpieces of Gadeb 8D are usually unifacial denticulates and side-scrapers with no clear typological standardization (Fig 21)Nevertheless as with Gadeb 2B the edges of these small flakes andflake fragments seem to bemore intensively retouched and in someinstances (eg Fig 21 4) shaped into bifacial pointed artefacts

Gadeb 8D has a considerable number of handaxes (n frac14 38)which make up 157 of the knapped assemblage the samepercentage as flakes (Fig 3) Their relevance in the assemblagecomposition is even more obvious when looking at their overallweight contribution (Table 3) in which handaxe total weight(w20 kg) represents the largest investment of raw material Mosthandaxes have slightly abraded (649) or fresh (27) edgeswhereas only a few are abraded (243) or heavily abraded (54)Therefore most Gadeb 8D handaxes probably did not undergoheavy transportation processes and may have been recovered closeto their original position In a sample of 26 handaxes 615 werepredominantly cortical (ie cortex gt50) including 77 withcompletely cortical dorsal surfaces An additional 192 show lt50cortex and only a few pieces (192) are non-cortical The highpercentage of cortex suggests non-intensive shaping which is alsosupported by the average scar count (741 scars per piece)

Nonetheless there is a high variability in the intensity of faccedilonnage(Fig 22) from pieces with no or very few extractions to somehandaxes that have up to 22 scars

Of the whole sample of handaxes (n frac14 38) 514 are on flakesand 297 on cobbles The remaining 189 are handaxes whereshaping was so intensive as to make it difficult to ascertain theoriginal blank With an average length and weight of w15 cm andw530 g for the whole sample of handaxes (see Table 4) thereseems to be some size differences between those made from flakesand cobbles Handaxes on flakes are on average 1601 mm long andweigh 6242 g whereas those on cobbles are smaller (meanlength frac14 1414 mm) and lighter (5131 g)

On technological and typological grounds 216 of the 38 han-daxes were classified as bifaces 378 as knives 27 (ie just one)as a cleaver and the rest (378) were considered under the generalterm of LCTs as defined by Isaac (1977) in Olorgesailie and dis-cussed for Olduvai (de la Torre and Mora 2005) and Peninj (de laTorre et al 2008) The term LCT is not exclusive with respect tothe other categories (in fact bifaces knives and cleavers fromGadeb8D can all be classified as LCTs) but it was applied to those piecesthat would fit in neither of the former categories

Knives (as defined by Kleindienst (1962)) in Gadeb 8D resemblethose from Peninj (de la Torre et al 2008) and could be consideredas large massive sidescrapers made on flakes with one or twodenticulated edges opposite a blunt end (Figs 22 and 23) Gadeb 8Dknives usually do not even show shaping of tips (common in Peninj)although the removal of butts andor the thinning of ventral bulbsare not rare Although no LCT cores have been found in Gadeb 8Dfeatures displayed by knives provide relevant information on flakingmethods As such extraction technology of large flake knife blanksis remarkably simple A preponderance of flakeswith largely cortical

Figure 11 Small retouched flakes in Gadeb 2E


dorsal sides and butts (some of the knives are actually 100 cortical)suggest that completely unmodified large cobbles were struck withno previous preparationwhatsoever The few scars displayed on theknives are normally secondary (ie they belong to the shapingprocesses) therefore indicating that preparation of large cobblecores (probably no larger than 20 cm according to flakemorphology

and size) simply did not exist Apparently forceful blows on suitableangles of natural cobbles were adequate to flake the short wide andthick blanks used to shape knives

Alongside knives Gadeb 8D has a variety of unifacial shapedtools made on blocks or have no blunt edges and which can beconsidered under the rather general name of LCTs Figs 22 and 24

Figure 12 Pointed retouched tools at Gadeb 2E


show some of these pieces Here retouch is identical to that on theknives (ie denticulated modification of edges with sinuousoutlines) Shaping is also very similar basically unifacial and withno attempts to achieve biconvex and symmetrical volumes sepa-rated by continuous edges As in the case of knives these ldquounca-tegorizedrdquo LCTs can hardly be considered as bifaces for they areactually characterised by unifacial shaping which is rathercommon for LCTs that display largely cortical faces These artefacts

are quite abundant in Gadeb 8D and very characteristic of Gadeb 8Fand had been specifically termed unifaces (eg Clark 1996)

To sum up among the knives and other LCTs retouch is notcontinuous along the perimeter and there are no straight edges dueto the denticulated form of retouch This retouch is limited to theedges and at a wide angle as opposed to that which is flat invasiveand shapes the pieces There is rarely intersection of extractions fromthe opposite edges of pieces and therefore there is no management

Figure 13 Examples of the LCT chaicircne opeacuteratoire in Gadeb 2E The shaped ignimbrite flake (1) originally considered as a core (Kurashina 1978) shows scars on the dorsal andventral sides and weighs w3540 g Pieces (2) and (3) have no secondary retouch but attest to the presence of large flakes on site


of central volumes In short knives and other LCTs seem to representshaping processes in which the knappers were not interested inachieving bifacial forms with biconvex and bilateral symmetry Onthe contrary the aim seems to have been to get heavy-duty toolswith robust edges irrespectively of their overall shape

LCTs make up 784 of the assemblage and only the remainingpieces can be considered as proper bifaces Those bifaces (see

examples in Figs 22 and 24) do seem to represent an attempt tomanage the central volume of handaxes through intersection ofextractions from either edge of the piece and an effort to balance thebilateral convexity through bifacial interaction of surfaces Howevereven these bifaces seem to fail in the management of the centralvolume As evidenced by the stepped scars and the progressivelymore abrupt angle of negatives bifaces show successive attempts to

Figure 14 Elements of the small debitage chaicircne opeacuteratoire in Gadeb 2C (1) Core on cobble (2) Core on flake (3) Core on fragment (4e6) Denticulated flakes


reduce the central volume of surfaces which were consistentlyunsuccessful Whether this failed reduction of volume is due to thetechnical incompetence of knappers or caused by raw materialconstraints (the latter being an issue yet to be studied) is a rathermore complicated question to address

The Gadeb 8F assemblage

Gadeb 8F is at the top of the Mio Goro Formation in the Gadeb 8locality and is likely the youngest of all Gadeb sites It is also theassemblage with the highest percentage of fresh (684) artefactsfollowed by those that are slightly abraded (226) and a very smallpercentage of abraded (90) pieces (see SOM Fig 1A) Although thesmallest lithic fraction is missing Gadeb 8F is certainly the leastdisturbed assemblage of the entire Gadeb sample This allowsa more accurate assessment of the links between reductionsequence elements than in other assemblages Discrepanciesbetween Kurashinarsquos (1978) recounts and those in this paper arehigher than in Gadeb 2C Gadeb 2B and Gadeb 8D although Table 2shows that divergences occur basically in the technologically leastimportant categories (unmodified blocks angular and flake frag-ments) whereas the main groups (cores shaped tools percussive

artefacts flakes) are well represented and small variations onrecounts correspond to different analytical perspectives

Flakes predominate in Gadeb 8F (see Table 2 and Fig 3) witha total (nfrac14 48) nearly identical to that from Gadeb 2C (nfrac14 50) butwhich was part of an assemblage three times larger This propor-tionally higher number of flakes in Gadeb 8F reinforces the notionof better taphonomic preservation of debitage activities at Gadeb8F when compared with other assemblages Gadeb 8F flakes havean average length of approximately 5 cm larger than the othersites except for Gadeb 8D (Table 4) Indeed 292 of the flakes arelarger than 6 cm (see also Fig 4A) Cortex either on butts (Fig 4B)or dorsal faces (Fig 4C) is common with only 104 of whole flakesbeing completely non-cortical This conforms to dorsal surfaceflaking patterns With an average of 238 negatives per flake fewdorsal surfaces have 3e4 scars or more (Fig 4D) Although a fewedge-core flakes (SOM Fig 15) indicate reorganization of flaking insome instances generally the flaking direction of previous scars(Fig 16) suggests little rotation of cores and predominance ofunidirectional patterns In short Gadeb 8F flakes indicate non-intensive reduction patterns of usually unidirectional cores aimedto obtain w5 cm flakes with no morphological standardization(SOM Fig 16)

Figure 15 Gadeb 2C handaxes Both pieces (especially 1) have fresh edges and attest to the presence of LCT elements in the assemblage


Figure 16 Scar patterns on dorsal sides of flakes in the Gadeb assemblages following Castantildeedarsquos (1999) design


Cores (n frac14 26) represent 196 of the assemblage angularfragments and unmodified material excluded (Fig 3) and are onlypartially consistent with the data derived from the flakes Forexample many flakes are consistently larger than expected fromcore dimensions core length averages w78 mm (Fig 6A) and themeanweight is 420 g (Table 3) However there is great variability insize with some cores as small as 33 mm and 45 g Despite this

variability all of the Gadeb 8F cores can be assigned to small deb-itage reduction sequences (no LCT cores were found in theassemblage) but there is a great shortage of flakes matching thereduced dimensions of many cores Other inconsistencies areevident between flake and core patterns For example althoughmost cores still preserve cortical surfaces (Fig 6C) Gadeb 8F showsby far the highest number of scars per core (919) of all assemblages

Figure 17 Examples of Gadeb 2B cores


Figure 18 Small retouched pieces in Gadeb 2B


(Fig 6B) Therefore reduction intensity as deduced from cores ishigher than expected from the analysis of flakes

Core exploitation methods (Fig 9 and Table 5) show a predom-inance (682) of unifacial (USP UAU1 UAU2 UAT UP) over bifacialsystems Reduction of independent surfaces by abrupt flaking(UAU1 UAU2 UAUT) is the most common some cores indicate verysimple flaking sequences where cortical striking platforms are used

to get short series of flakes from single knapping surfaces Othersshow exploitation of independent surfaces (ie with no interactionbetween planes) through the flaking of short unidirectional andabrupt-angled series of flakes (eg Fig 25 3 and Fig 26 4) Ingeneral this is an expedient strategy in which surfaces are aban-doned as soon as angles become too obtuse either by discardingthe core or by seeking another flaking surface The latter may

Figure 19 Large unmodified flakes (2) and LCTs (1 3e5) in Gadeb 2B


Figure 20 Radial cores in Gadeb 8D


explain the presence of some edge-core flakes as these do not seemto refer to rejuvenation processes but to independently exploitedsurfaces (see again SOM Fig 15)

Chopper-like knapping methods (USP BSP) represented inGadeb 8F (see Fig 26) also indicate short reduction sequencesOther cores show longer exploitation series such as in BALP BALTand UP examples (Figs 25 and 26) the first two indicate mainte-nance of a bifacial edge that organizes flaking and UP cores illus-trate full rotation of cores following the same exploitation surfaceHowever all in all Gadeb 8F cores do not show structured orcomplex reduction sequences maintained through long exploita-tion processes Quite the opposite the knappingmethods are ratherexpedient and reflect little ability andor interest on the mainte-nance of flaking efficiency However some cores are surprisinglysmall (with several examples under 5 cm length) casting doubts onthe utility of resulting flakes and impeding a conclusive assessmentof flaking intensity and knapping methods involved

An evaluation of retouching processes in Gadeb 8F is alsocomplicated Whereas in other Gadeb sites there is a neat size andtechnological break between small retouched tool and LCT blanksin Gadeb 8F there seems to be a continuum in size of shapedartefacts This complicates assigning pieces to one or anotherchaicircne opeacuteratoire which is made even more difficult as severalartefacts do not reach the 10 cm threshold traditionally proposedfor handaxes (Kleindienst 1962) This flow between shaped tool

types has long been recognised (eg Isaac 1977) and is particularlymeaningful in the case of Gadeb 8F Here strategies employed toget blanks for shaped tools cannot be used as the only criterion toseparate retouched forms and it is the type of retouch and thetypology of artefacts itself that seem to drive shaping patterns

On these grounds the number of small retouched tools asrecounted in Table 2 and Fig 3 should be seen as an arbitrary groupbased on size measurements but which is in many ways similar tothat of pieces classified as LCTs This continuum will be discussedbelow but what should be stressed here is the high number(n frac14 34) of small retouched pieces in Gadeb 8F which makes up23 of the artefacts (Fig 3) the highest percentage of small shapedtools of all Gadeb sites 559 of small retouched tools are made onflake fragments 412 on complete flakes and just one (29) ona cobble The average length of small retouched pieces (approxi-mately 6 cm) differs little fromother sites (Table 4) Part of the Gadeb8F retouched pieces sample shares the same typological character-istics as the other assemblages ie irregular retouch on sinuous anddenticulated edges However Gadeb 8F also contains a significantnumber of artefacts with finely made retouch which consistentlymodifies flake edges and creates pointed forms (Fig 27)

This trend towards more typological sophistication becomesespecially evident in what here will be called unifaces (after Clark1996) These unifaces also named unifacial handaxes (Clark 2001)show a continuum of size typology and technology which blur

Figure 21 Small retouched pieces in Gadeb 8D


differences between the reduction sequences of small debitage andLCTs Originally described as ldquoa special local form of scraper andbiface [which] is made on a cobble flake the retouch being confinedto the ventral or flake surface while the dorsal face is formed onlyby cortexrdquo (Clark 1980 193) these pieces resemble some of thosedescribed in Gadeb 8D (eg Fig 23 3 5) and in particular showremarkable technological and typological standardization Exam-ples from Figs 28 and 29 (but also the small ones from Fig 27 2and 3 proving the size continuum of these morphologies) showexactly the same shaping technique a flat and cortical surface is

used as a knapping platform for shaping a pointed tool throughintensive retouch of the opposite face

The shaping technique is quite standardized There is noexchange of flaking and striking surfaces but a rigid maintenanceof the same scheme of faccedilonnage On those made on flakes or splitcobbles the dorsal face is always selected as the striking platform toshape the ventral side On cobbles the flatter side is used as strikingplatform In both cases there seems to be a conscious selection ofplanar-convex blanks in which the flat surface is consistently usedas a knapping platform to shape the opposing convexity Whereas

Figure 22 Handaxes from Gadeb 8D (1) This knife is one of the most heavily shaped pieces in the assemblage Nevertheless there is practically no bifacial retouch and the ventralface is largely unretouched with the exception of the removal of the butt and bulb There is little bifacial symmetry and the distribution of volumes is dictated by the original shapeof the flake with no further reorganization of convexities (2) Knife made on a wide and short flake Butt and dorsal face were originally cortical although the butt has almost beenentirely removed through retouch Apart from that the ventral face is predominantly unretouched whereas the dorsal face shows retouch on part of its periphery but restricted tothe edge and therefore non-invasive (3) LCT on flake The butt and the dorsal face preserve large amounts of fluvial cortex The dorsal face shows little retouch and the ventral faceis retouched throughout its entire periphery but is predominantly non-invasive (4) LCT on a predominantly cortical cobble whose perimeter is only partially shaped Retouch isprimarily unifacial with shaping of an edge from one surface of the cobble and the other surface from the opposite edge -see description of a similar (but not identical) ldquorhomboidaltechniquerdquo in de la Torre and Mora (2005)


Figure 23 Handaxes from Gadeb 8D (1) Biface on cobble Retouch is bifacial and shapes the tip and the two edges of the blank attempting some kind of bifacial symmetryHowever there is poor management of bifacial volumes and central parts of the two opposing faces which retain large cortical surfaces (2) Knife on a short and wide flake largelyunmodified in which shaping of the ventral face is practically restricted to the removal of the buttbulb and retouching of the dorsal face is non-invasive and denticulated (3) Knifemade on a completely cortical flake Retouch is limited to the ventral face and focused on the removal of the buttbulb The rest of the perimeter shows marginal and sinuous



most LCTs described in other sites showmarginal retouch restrictedto the edge of pieces retouch in Gadeb 8F unifaces aims to reducecentral volumes through invasive shaping However it is significantthat the central shaped volume of nearly all pieces in Figs 28 and 29is considerably limited by several lines of step scars around theentire uniface perimeter This consecutive stepping of centralvolumes was probably caused by wide flaking angles (simple orsemi-abrupt) as opposed to the flat- angled shaping that wouldhave been required to successfully reduce the central surfaces ofblanks Given the standardization of these unifaces and the carefulshaping of edges on some pieces it could be argued that the thicksections resulting from stepped central volumes were not knappingaccidents but the outcome of intentional scalariform retouch

Although the term lsquobifacersquo is obviously unsuitable for thesepieces most would agree that many examples from Figs 28 and 29fit comfortablywithin the rather lax category of handaxes The termbiface would also be inappropriate for the smaller unifaces whichas argued here share exactly the same technological and typolog-ical principles as the larger ones This dilemma which is purelyterminological and probably a meaningless one reflects the flexibleand pragmatic application in Gadeb 8F of very specific mentaltemplates to blanks obtained through different methods flakesfrom small debitage sequences split or complete cobbles etc

Gadeb 8F also has some elements more clearly associated withthe production of LCTs among them a cleaver made on a large(more than 1 kg) flake and a couple of sidescrapers on flake blanksthat do not belong to the small debitage chaicircne opeacuteratoire (Fig 30)Interestingly the large cleaver more closely resembles the LCTsfrom other Gadeb assemblages with denticulated and marginalretouch basically focused on the thinning of the bulb than to theunifaces described above reinforcing the peculiar traits of theGadeb 8F unifacial handaxes

Finally the presence of percussive tools in Gadeb 8F must behighlighted Although numerically (nfrac14 17) unimportant in terms ofrawmaterial weight (more than 15 kg see Table 3) battered artefactsare the largest group As in Gadeb 2E most battered tools arehammerstones with fractured angles (824) followed by regularhammerstones (118) and anvils (one only 59) The hammer-stones with fractured angles are large (mean length frac14 912 mm) andheavy cobbles (meanweightfrac14 9455 g) which usually have a heavilypounded area opposite a cortical and largely unmodified surface Theunevenness of battered surfaces and abundance of irregular ridgesprevent consideration of these pieces as regular hammerstonestypically used for knapping However given the doubt about theassociation of fossils and artefacts (see above) at present it is difficultto assert the technological and functional significance of theseartefacts

Inter-assemblage variability of the Gadeb sites

The aim of descriptions in the above sections has been topresent the individual characteristic features of cores flakes sha-ped and battered tools in each of the Gadeb assemblagesSummaries of their main traits and inter-assemblage comparisonscan now be made

Fragmentation of reduction sequences is one of the mostdefining features of all assemblages This fragmentation is bothtaphonomic and behavioural the former refers to post-deposi-tional processes causing acute shortage of debitage in contrast

retouch and not even the tip is bifacially or more carefully shaped (4) Originally classified acompletely unretouched and the dorsal face shows only a couple of secondary scars This piboth the dorsal face and the butt show some preparation of the large core prior to the extcompletely cortical and the ventral face shows thinning of the bulb The opposite distal en

with an overabundance of core forms But there is also an imbal-ance in the representation of some categories that probablycorresponds to knapper decision-making This refers to the pres-ence of handaxes usually made on large flakes but for which coresand other expected debitage by-products are missing Thereforethis fragmentation of the reduction sequence of large shaped tools(which applies to all sites under study) involves off site production(and arguably also faccedilonnage) of large blanks This fragmentation isintimately linked to the recurring coexistence of two chaicircnesopeacuteratoires All of the Gadeb sites studied contain abundant coresassociated with the flaking of small debitage but all these assem-blages also include large shaped tools on flakes clearly obtainedthrough a different chaicircne opeacuteratoire that of LCTs

Table 6 summarizes proportional frequencies of meaningfultechnological traits indicated by inter-assemblage comparisonFirstly it is observed that exploitation of very small cores (less than5 cm) occurred in all sites under study Figs 7 8 10 17 20 and 26show that Gadeb knappers often reduced very tiny blanks whichalthough usually do not present complex organization of flakingdemonstrate the knappersrsquo ability tomanipulate difficult-to-handlecores Given the local abundance of cobbles (as presumed from thematrix conglomerates high numbers of unmodified cobbles in theassemblages and larger dimensions of other cores) the availabilityof raw material cannot be put forward as an explanation for thediminutive size of some cores The functional meaning of resultingflakes is also difficult to assess given their remarkably small sizeIntensity of reduction is not a satisfactory explanation either asmany of these small cores show short sequences of flaking and havelargely cortical surfaces This indicates that the original blanksselected as cores were already tiny forms Whatever the case thefact that these very particular cores appear regularly in all Gadebsites could suggest shared technological patterns which are diffi-cult to comprehend through strictly cost-benefit explanations

Another inter-assemblage trend is the rare occurrence ofstructured flaking methods Knapping systems that require rigidhierarchization of flaking and striking surfaces (BHC) or dynamicinteraction between both planes (eg discoid) only appear occa-sionally (see Table 6) Clark and Kurashina (1976) mentioned thepresence of lsquoproto- Levalloisrsquo cores in Gadeb 8A and Kurashina(1978) reported predominance of lsquobiconicalrsquo cores in Gadeb 8Ewhich are all probably similar to those described here for Gadeb 2Eand 8D However in general terms the flaking methods of Gadebcores are rather expedient with short reduction sequences overlycortical surfaces lack of standardization in knapping methods andgreat size variability It can thus be stated that Gadeb knapperswere selecting cobbles of various sizes (usually 5e10 cm long)removing a few flakes (inter-assemblage average of 71 scars percore) and abandoning cores without attempts to reactivate flakingangles In this case the abundance of local raw materials mightexplain the expedient flaking pattern evident in all Gadeb sites

The relative abundance of small retouched tools is anothergeneral pattern especially in Gadeb 2B 8D and 8F This is unlikelyto be a temporal trend as Gadeb 2B has the second highestpercentage of small retouched pieces and is stratigraphicallycontemporary with Gadeb 2C (see Fig 1) which has a lowfrequency of these tools Although the KruskaleWallis test (basedon average length) suggests that there is no inter-assemblage sizehomogeneity of small retouched pieces (H frac14 172 4 df p frac14 0002)they all share similar techno-typological traits Retouch is irregular

s a cleaver (Kurashina 1978) this piece is here considered as a knife The ventral face isece is technologically and typologically very similar to (5) although in the present caseraction of the LCT blank (5) Knife on a wide and short flake Dorsal face and butt ared displays denticulated retouch limited to the edge of the piece

Figure 24 Handaxes from Gadeb 8D (1) Biface made on cobble in which there is an attempt to balance bi-convexity of the two opposite surfaces through invasive retouchalthough this does not cover the whole perimeter of the artefact (2) Cleaver made on a predominantly cortical flake (3) LCT on flake This piece is practically identical to thoseconsidered as knives A wide and short flake is used as a blank shaped with denticulated and non-invasive retouch The butt is removed and the bulb thinned and there is nobiconvex reduction of volumes The only typological feature that could differentiate this example from a knife is that there is no blunt edge opposed to a ldquocuttingrdquo one (4) Bifacemade on a w11 cm flake Retouch is bifacial covers the whole perimeter of the piece and attempts to reduce the biconvex volumes (5) Biface made on a w12 cm flake Retouch isdenticulated and bifacial producing a pointed tool with rather asymmetrical distribution of volumes (6) LCT on cobble An elongated blank was selected to shape a pointed formApart from the bifacial shaping of the tip retouch is largely unifacial does not modify the central volumes of the cobble-only the edges and does not attempt to achievea biconvex symmetry


denticulated unifacial and marginal creating sinuous edges andnon-standardized shapes One possible exception might be Gadeb8F where alongside irregular retouches much more finely madesmall retouched tools also appear

Battered artefacts are relevant in only two of the sites studiedGadeb 2E and Gadeb 8F Regular knapping hammerstones wereprobably abundant in all sites but the ambiguity that these pieces

sometimes present when compared with natural cobbles mayexplain their low frequencies Anvils are relatively numerous inGadeb 2E (n frac14 14 115 of battered artefacts) but they are onlymarginally represented in Gadeb 8F and absent in other sitesSpecial attention is paid here to hammerstones with fractureangles as defined byMora and de la Torre (2005) Kurashina (1978)had already specified the relative abundance of such items (see

Figure 25 Diacritic schemes of Gadeb 8F cores (1) Possible biface reused as a core The volume is divided into two nearly symmetrical convexities and extractions intersect on thecentre of flaking surfaces leading to an optimummanagement of volumes The possible tip of the biface could have been on the right side of the piece as situated in the figure Be itor not a broken tip further flakes were detached after the fracture occurred (2) Small cobble used as a core with BALP flaking Cortex on both flaking surfaces indicates the originalsize of the cobble and the short reduction sequence (3) Example of UAU2 flaking in Gadeb 8F (4) BALP core on cobble


Table 2) which increases with the inclusion of some pieces origi-nally classified as sub-spheroids and polyhedrons These pieceshave been described above but their size and morphologicalhomogeneity must be noted The hammerstones with fractureangles from both Gadeb 2E and 8F are cobbles with one face heavilybattered opposed to a unmodified cortical surface (Fig 31)

In order for such extensive ridge damage to occur batteringactivities should have been remarkably intense in both sites Somehammerstones with fracture angles show smooth pitting on theircortical surfaces that could be due to their use as regular knappinghammers However the massive ridge damage on the oppositefaces caused irregular angles that are useless for knapping activities

Figure 26 Gadeb 8F cores (1) Bifacial chopper (BSP method) (2) BALP core (photograph in Fig 25 2) (3) Unifacial chopper (USP method) (4) Example of the UAU2 method Thiscore shows some battering on the distal end caused by bipolar damage which probably was alternated with free-hand flaking due to the very small size (less than 4 cm) of theblank (5) Corebroken biface (photograph and comments in Fig 25)


(see discussion in Mora and de la Torre 2005) Therefore activitiesconducted with these hammerstones with fracture angles musthave been different from those involving flaking and shaping ofother artefacts The Gadeb 2E and 8F battered artefacts are not only

morphologically similar but also remarkably alike in dimens-ions as supported by Studentrsquos t-tests (normal distribution verifiedwith one-sample KolmogoroveSmirnov tests) of length (2-tailedsig frac14 097) and weight (2-tailed sig frac14 043) This provides yet

Figure 27 Small retouched pieces in Gadeb 8F (2) and (3) could also be considered as small unifaces (see Figs 28 and 29)


Figure 28 Unifaces from Gadeb 8F (1) Uniface on flakesplit cobble (2) Broken tip of uniface (3) Uniface on flakesplit cobble (4 and 6) Uniface on flake (5 and 8) Uniface on flakeflake fragment (7) Uniface on cobble


another argument to sustain the functional particularities of bat-tered tools in both assemblages

Whereas battering activities seem to have been relevant onlyin Gadeb 2E and 8F the LTC chaicircne opeacuteratoire is present at all sitesstudied As summarized in Table 6 handaxes are especiallyabundant in Gadeb 8D but are also present in Gadeb 8F 2C 2Band to a minor extent in Gadeb 2E Although all of the handaxescould be included in the general classification of Large CuttingTools as defined by Isaac (1977) three main types of handaxesappear in the Gadeb assemblages The first group is one of typicalbifaces with more or less symmetrical bilateral and biconvexshapes A second group comprises the so-called unifaces afterClark (1996) characterised by very particular shaping methodscentred on the faccedilonnage of single faces opposed to corticalknapping platforms Finally a third group was here considered asknives (sensu Kleindienst 1962) and other heavy-duty formscharacterised by the poor volume management and the crudemodification of the edges of large flakes and to a minor extentcobbles

Since features of these handaxe groups have been detailed inprevious sections it is now relevant to discuss their inter-assem-blage composition knives and other ldquocruderdquo LCTs appear literally inall assemblages studied They show a strikingly similar pattern inwhich some large flakes (nearly all sites contain flake blanks over

1 kg) are obtained and probably shaped elsewhere co-occurringwith a much larger sample of elements belonging to the smalldebitage chaicircne opeacuteratoire Proper bifaces appear preferentiallyin Gadeb 8D and unifaces are characteristic of Gadeb 8F Giventhe small number of true bifaces in Gadeb 8D (n frac14 8 out of 37handaxes) it could tentatively be argued that their absence in otherassemblages is due to the smaller sample of LCTs at those sites Intruth none of the Gadeb 8D bifaces are too different from otherhandaxes regarding size blanks etc and the only distinction maylie on a larger reduction sequence of bifacial shapes The case ofunifaces is arguably different Although some similar pieces occurin Gadeb 8D unifaces are idiosyncratic of Gadeb 8F As discussedabove there is a continuum of size and morphology among uni-faces from small retouched pieces to handaxes gt10 cm all withcortical faces opposed to extensively shaped faces In this case thereis no clear distinction between elements of the small debitage andLCT chaicircne opeacuteratoire and all suggests the application of specificmental templates to the shaping of tools in Gadeb 8F regardless ofsize In other words in Gadeb 8F there is evidence for a kind oftechnical idiosyncrasy that may allow for local (and probably veryparticular) technological trends

In sum it can be argued that with reference to the LCT chaicircneopeacuteratoire the twomain aspects of inter-assemblage variability arethe different percentages of handaxes (with Gadeb 8D and 2E

Figure 29 Unifaces from Gadeb 8F the same examples as in Fig 28 and in the same order


having the highest and lowest percentages respectively) and theparticular traits of the Gadeb 8F unifaces Apart from that thehandaxe chaicircne opeacuteratoire is remarkably similar in all sites withprevalence of rather unstructured LCTs and pieces made on largeflakes for which their cores are lacking indicating a fragmentationof the reduction sequence from quarry to site

Those similarities are not only qualitative but can also be verifiedby quantitative patterns Whereas non-parametric tests could notprove similarities between small debitage cores (hence emphasizingthe inter-assemblage variability aforementioned) KruskaleWallistests of several handaxe features seem to suggest contrasting resultsComparisons of length (H frac14 292 4 df p frac14 057) scar count(H frac14 308 3 df p frac14 037) percentage of cortex (H frac14 678 4 dfpfrac14 048) and handaxe blanks (Hfrac14 352 4 df pfrac14 047) attest to thesimilarity of LCTs from all sites

Therefore qualitative and quantitative arguments lead to theconclusion that no obvious differences exist between handaxesfrom the five sites under study These conclusions could tentativelybe extended to Gadeb 8E an assemblage not included in this studybut for which a detailed report is available (Clark and Kurashina1979b) According to these authors split and whole cobbles andside and end-struck flakes were used as blanks for handaxes andcleavers Clark and Kurashina (1979b) recognised unifacial and fullybifacial LCTs but reported that the most common pieces were whatthey called partial-bifacial retouched artefacts in which minimum

retouch was present Overall Gadeb 8E pieces appear not be toodifferent from those described in this paper which is not surprisinggiven the similar stratigraphic position of Gadeb 8E and Gadeb 8D(Clark and Kurashina 1979a) Nevertheless at Gadeb 8A (also in thesame stratigraphic position and only 800 m north of Gadeb 8D)there seems to be a prevalence of proper bifaces and even soft-hammer technique (Kurashina 1978) which has not been observedin the assemblages studied here

Once inter-assemblage variability for each individual categoryhas been summarized the overall composition of each assemblageshall be discussed In Gadeb 2E the co-occurrence of three differentchaicircnes opeacuteratoires must be emphasized The production of smalldebitage appears alongside large blanks typical of the LCT chaicircneopeacuteratoire and heavily battered artefacts unrelated to knappingactivities form a third group of stone tool useproduction Knappingmethods are varied from structured flaking systems to ratherexpedient ones Size variability is also high from cores less than4 cm to some heavier than 2 kg Small retouched pieces are scarcein stark contrast with other Gadeb sites However the lowpercentage of handaxes does not mean that the LCT chaicircne opeacuter-atoire is underrepresented While Gadeb 2E may have the lowestnumber of LCTs of all of the Gadeb sites it also contains the highestamount of unmodified large flakes (nearly a dozen including severalweighingmore than 1 kg) which could be considered as potentialLCT blanks When these pieces are taken into account the number

Figure 30 Elements of the LCT chaicircne opeacuteratoire in Gadeb 8F (1 2) Scalariform sidescrapers on large flakes (3) Cleaver

Table 6Proportional relevance of the main lithic elements according to intra and inter-assemblage percentages based on data from Tables 2 and 5 Figs 6 and 9


Diminutive cores thorn thorn thornthornthorn thornthorn thornthornStructured cores thornthorn e e thorn e

Small retouches thorn thorn thornthorn thornthorn thornthornthornLCT cores e e e e e

Handaxes thorn thornthorn thornthorn thornthornthorn thornthornBattered tools thornthornthorn thorn thorn e thornthorn


of elements that can be attributed to typically Acheulean technol-ogies increases significantly

The Gadeb 2C assemblage contains elements of the small deb-itage and LCTs chaicircnes opeacuteratoires Knapping methods are usuallyexpedient with short reduction sequences and poor maintenanceof flaking angles Size variability is also high and diminutive coressuch as those in Gadeb 2E and other assemblages suggest knappersrsquomanual dexterity Small retouched pieces are more abundant thanin Gadeb 2E although substantially less numerous than in the othersites The LCT chaicircne opeacuteratoire is attested residually but indicatesflaking of large blanks that were then turned into handaxes

Figure 31 Hammerstones with fracture angles from Gadeb 2E (1e4) and Gadeb 8F (5 6)


Gadeb 2B also yielded materials attributable to the small deb-itage and LCTchaicircnes opeacuteratoires The latter is not only representedby handaxes but also by some unretouched large flakes producedwithin the LCT reduction sequence However there are few largeshaped elements which contrast with the high percentage of smallretouched tools As a whole Gadeb 2B seems to be characterized byquite simple knapping methods some elements of the LCT reduc-tion sequence and above all by high numbers of small and non-standardized retouched pieces The assemblage of Gadeb 8D hassimilar traits to Gadeb 2B Small debitage reduction sequencespredominate knapping methods are generally expedient there aremany small and unstructured retouched pieces handaxes are notintensively shaped and there are no LCTcores It is true that there is

a substantially larger number of LCTs but this is the only differencewith the other assemblages

Gadeb 8F is probably the most idiosyncratic of all of the Gadebsites due to particularities of its shaped tools These tools showa size and morphological continuum which highlights a strongpredetermination of shape templates but also dilutes the cleardifferences found in other assemblages between the small debitageand LCT chaicircnes opeacuteratoires (eg SOM Fig 17) Despite thesepeculiarities Gadeb 8F fits within the same patterns described forthe other assemblages with a predominance of small debitagesequences simple reduction methods a high number of smallretouched pieces some LCT blanks and spacetime fragmentationof this typically Acheulean chaicircne opeacuteratoire

Figure 32 Handaxes in the Gadeb assemblages (1e3) Gadeb 8F (4) Gadeb 2E (5e7) Gadeb 8E (8) Gadeb 8D (9) Gadeb 2A (10) Gadeb 2B (11) Gadeb 2C



The main point to make here is that Gadeb assemblages show notechnical divergences that could justify their assignment to differentculturalfunctionaltechnological traditions Relative frequencies ofsome categories such as battered tools small retouched pieces orhandaxes do vary but the underlying technological strategies arethe same in all assemblages There is a predominance of smalldebitage reduction systems (usually expedient ones) which co-occur with variable numbers of small retouched pieces and LCTs onlarge flakes and blocks in general only partially shaped This latterchaicircne opeacuteratoire invariably appears fragmented with the largeblanks being flaked off site and transported to the site either asshaped artefacts or large flake blanks Of course some qualitativeand especially quantitative inter-assemblage variability existsparticularly in the composition of LCTs but the technologicalbackground is the same This could be valid not only for the sitesdescribed in this paper but also elsewhere in Gadeb (Fig 32)Therefore should this point on the overall homogeneity of assem-blages be accepted what needs to be considered now is the rela-tionship of the Gadeb assemblages to other ESA sites and theresulting implications for the understanding of early stone tooltechnologies in Eastern Africa

Gadeb and the Developed Oldowanearly Acheulean debate inEast Africa

The long and uncertain time interval of the Gadeb assemblagesbetween 145 and 07 Ma poses two different archaeological prob-lems the origins of the Acheulean and the inter-assemblage vari-ability of lithic technologies at the end of the Lower Pleistocene Inrecent years much effort has been invested in dating the earliestAcheulean and presently there is solid evidence placing the originsof this technology in East Africa at 17e16 Ma (Asfaw et al 1992Roche et al 2003 Quade et al 2004) However the technologicalchange that led to the emergence of the Acheulean is still poorlyunderstood despite ongoing discussions (eg Leakey 1971 1975Bower 1977 Stiles 1977 Gowlett 1988 de la Torre and Mora2005 de la Torre 2009 Semaw et al 2009) Not only is it unclearhow and why small debitage methods typical of the Oldowan gaveway to Acheulean technology based on the production of hugeblanks made into shaped tools but the status of industries lackinghandaxes after the appearance of the Acheulean is also uncertain Toaddress this second issue Leakey (eg 1967) coined the termDeveloped Oldowan Immediately popularised after the publicationof the classic monograph on Olduvai Beds I and II (Leakey 1971) theconcept of Developed Oldowan provided a straightforward way tocategorize assemblages and assign them to different cultural andeven biological fila As the long standing debate on the DevelopedOldowan versus Acheulean in Olduvai Gorge has been summarizedelsewhere (de la Torre andMora 2005 225-228) it may seemmorerelevant now to discuss its implications for the interpretation ofother East African assemblages

Leakey (1971 1994) used several factors to assign assemblageseither to the Developed Oldowan B or the Acheulean such as theblank types used to shape handaxes biface size and morphologyand relative frequencies of handaxes This latter factor followedKleindienstrsquos (1962) original proposal in which an assemblagemust contain 40 of handaxes or more in the tools group for it to beconsidered Acheulean Therefore whereas other arguments posedby Leakey (1971) were based on her own observations at OlduvaiMiddle and Upper Bed II the requisite of handaxe frequencies fol-lowed a study of more recent assemblages (Kleindienst 1962)Curiously enough although all authors employing the termDeveloped Oldowan followed Leakeyrsquos definition peculiarities ofeach archaeological sequence preclude the use of most traits oncedefined in Olduvai with the result that handaxe frequency has been

the more extensively used criterion to consider sites as eitherDeveloped Oldowan or Acheulean This is not to say that authorsadhered strictly to the rather arbitrary 40 handaxe threshold onceproposed by Kleindienst (1962) but that very low percentages ofhandaxes have been used as a main criterion to classify DevelopedOldowan sites across East Africa From the inception of the term inOlduvai (Leakey 1967 1971) Developed Oldowan sites have beennamed in a significant number of East African early Pleistocenesequences such as Chesowanja (Harris and Gowlett 1980) KoobiFora (Braun et al 2008) West Turkana (Texier et al 2006) MelkaKunture (Chavaillon and Piperno 2004) Middle Awash (Clark et al1984) and of course Gadeb (eg Clark and Kurashina 1979a)

This dichotomy between assemblages with and without han-daxes is not limited to the time period concerning the earliestemergence of the Acheulean but seems to be a recurrent pattern inEast Africa during the late Early Pleistocene and through theMiddlePleistocene Leakey (1994) described a number of assemblages inOlduvai Beds III and IV with few or no handaxes and which were inher opinion a continuation of the Developed Oldowan B but nowtermed Developed Oldowan C In Olorgesailie the Hope MountainIndustry (Posnasky 1959) was compared with handaxe assem-blages (Isaac 1977) and placed according to the ecological distri-bution of sites (Potts 2001) In the late Lower Pleistocene andthroughout the Middle Pleistocene assemblages with and withouthandaxes are also found in Middle Awash and are again related tovariable environmental settings (de Heinzelin et al 2000) In WestTurkana Middle Pleistocene sites have been reported with largeassemblages but in which no handaxes are present (Delagnes et al2006) and a similar pattern is documented in the Late Acheulean ofKapthurin (McBrearty 2001) Therefore in East Africa it is welldocumented that small debitage chaicircnes opeacuteratoires were exten-sively used after the emergence of the Acheulean and throughoutthe development of this techno-complex either in co-occurrencewith handaxes or without them

Traditional interpretations of technological change linked novelcultures to the emergence of new human species The classicexplanation of inter-assemblage variability in Olduvai from MiddleBed II onwards associated Homo habilis with the Developed Old-owan and the new Homo erectuswith the Acheulean (Leakey 1971)It could be argued that as Mary Leakeyrsquos type list was deeplyinfluenced by F Bordesrsquo typology (de la Torre and Mora 2009) soalso was her interpretation of inter-assemblage variability IndeedLeakeyrsquos correlation of industries and hominins was not toodifferent from the interpretation of Mousterian facies proposed byBordes (eg Bordes and Sonneville-Bordes 1970) Nonethelessdirect associations between homininscultures and technologies areproblematic especially when long coexistence of different speciesof Homo has now begun to be demonstrated (Spoor et al 2007)

Functional interpretations of inter-assemblage variability wereproposed earlier than usually acknowledged For example Posnasky(1959) proposed that the presence of some handaxe-free assem-blages in Olorgesailie was not explained by cultural divergences butdue to the different set of activities conducted Probably the mostpopular interpretation of this inter-assemblage variability is thatbased on ecological variables Although this hypothesis is widelyattributed to Hay (1976) it was Isaac (1971) who first proposed it asacknowledged by Hay (1990) himself Both authors suggest that thelocation near the lake shore of most Developed Oldowan sites atOlduvai in contrast to the inland-riverine environments of earlyAcheulean sites could indicate different activities in a variety ofecological settings by the same groups of hominins This hypothesiswhich moves away from culture-history explanations such as Lea-keyrsquos has been widely used to understand variable frequencies ofhandaxes in Olorgesailie (eg Potts et al 1999) and Middle Awash(de Heinzelin et al 2000) for instance However it has been argued


that such a dichotomy (Acheulean frac14 fluvial environments versusDeveloped Oldowan frac14 lake shore settings) may be too rigid (de laTorre 2008 185-191) Sometimes undisputable Acheulean sitesappear in lake-margin environments such as Konso (Beyene et al1996) or West Turkana (Roche et al 2003) while there are chro-nologically contemporary assemblages in riverine environments thatcontain only a few handaxes such as some of the Melka Kunturesites (Chavaillon and Piperno 2004) or Gadeb itself (Clark andKurashina 1979a this paper)

Despite the above reservations the potential of the ecologicalhypothesis is that it allows an approach to inter-assemblage vari-ability via a functional compartmentalization of landscape ratherthan through links between industries and particular humanspecies It has been proposed elsewhere that this problem can beaddressed on technological grounds (de la Torre 2008) Forexample the use of handaxe percentages as a proxy for assemblagecharacterization can be challenged In functional terms it is truehandaxe frequency in an assemblage must have a meaning A largeconcentration of handaxes in one particular spot will definitely bethe result of a different activitybehaviour to that where handaxesare scarce or absent However to paraphrase Gowlett (1986) wheretechnological ability per se is concerned one handaxe is the sameas forty Quantity of objects is irrelevant and the presence of largecutting tools with particular morphologies regardless of numberimply that knappers had the cognitive and practical skills tomanufacture these tools Following Lemonnier (1990) here it isassumed that the adoption of any innovation (in this case Acheu-lean technology) be it local or imported automatically implies thatsuch an innovation (raw material requirements manufacturingtools know-how functional connotations etc) is fully understoodby knappers From this viewpoint quantitative discussions are notvery useful If an assemblage contains handaxes it means that therequired technological and cognitive skills to produce them arepresent and therefore the site belongs to the same techno-complexas any other where handaxes are plentiful even if their functionalroles differ

If handaxe frequency is ruled out as a valid criterion the samecan apply to LCT morphology and blanks other indicators onceemployed to discriminate between Developed Oldowan and theAcheulean (eg Leakey 1971) Handaxe morphology is ultimatelydictated by the blanks used Sometimes cobbles predominate overflake blanks such as at Gona (Semaw et al 2009) or flakes arepreferentially selected as occurs at EFHR in Olduvai (de la Torre andMora 2005) and at Mugulud and Bayasi in Peninj (de la Torre et al2008) In other instances tabular blocks are the most commonlyselected blanks for handaxes as in TK at Olduvai (de la Torre andMora 2005) Preferential selection of some blanks over otherscertainly has an impact on handaxe shape However as argued bySharon (2008) Acheulean LCT technology (or technologies) showremarkable similarities world-wide regardless of the rawmaterialsemployed To use examples from East Africa Lower Pleistocenehandaxes in Mugulud and Bayasi in Peninj (de la Torre et al 2008)Olduvai (de la Torre and Mora 2005) and Gadeb (this paper) allshow similar shaping methods in which faccedilonnage is usually con-strained to the edges of pieces and does not extend over wholesurfaces retouch is normally unifacial irregular and non-invasivepointed forms are sought and bifacial and bilateral symmetry isuncommon There is an application of preconceived morphologicaltemplates as pointed out by Isaac (1986) which are flexible andadapted to locally available raw materials as Clark (1980) onceclaimed

Therefore it is argued here that neither handaxe frequency norLCT morphology are consistent arguments to differentiate theDeveloped Oldowan from the Acheulean All the so-called Devel-oped Oldowan B sites in Olduvai have variable frequencies of

handaxes (de la Torre and Mora 2005) and the same applies toGadeb and others Therefore if the arguments presented above areaccepted they would all fit within the Acheulean techno-complexHowever what happens with those assemblages that postdate theemergence of the Acheulean but are without handaxes Althoughscarce lt16 Ma non-handaxe assemblages exist in the East AfricanEarly Stone Age as reported in Nyabusosi (Texier 1995) the PeninjST site complex (de la Torre et al 2003) Chesowanja (Gowlett et al1981) West Turkana (Delagnes et al 2006) Olorgesailie (Isaac1977) Middle Awash (de Heinzelin et al 2000) and othersWhereas the Acheulean character of Middle Pleistocene assem-blages is acknowledged by nearly all authors there is discussion asto whether or not early the lt16 Ma Pleistocene sites are stillOldowan

In the search for technological arguments to explain theabsence of handaxes it has been suggested that small debitagesystems could also provide a key to trace Acheulean technologies(Gowlett 1986 de la Torre 2008 2009) Gowlett (1986) suggestedthat bifacial flaking of discoid cores shares the same concepts andmental templates as handaxe production and therefore both mustbe interrelated On similar lines de la Torre (2008 2009) arguedthat complex debitage systems as reported originally in Nyabusosi(Texier 1995) and then in Peninj (de la Torre et al 2003) andOlduvai Middle and Upper Bed II (de la Torre and Mora 2005)appear concurrently with the first LCTs in East Africa In Peninj forexample assemblages with and without LCTs show almost iden-tical small debitage flaking methods in which structured strate-gies such as the bifacial hierarchical centripetal system prevail (dela Torre 2009) Since know-how and technical competence is thesame in both types of sites inter-assemblage variability isexplained by functional and ecological differences (de la Torre2009) Similarly it is symptomatic that a review of Olduvai Bed Iand II knapping methods (de la Torre and Mora 2005) onlyreported systematic appearance of small debitage structuredflaking systems in sites postdating the emergence of the Acheu-lean While belonging to different chaicircnes opeacuteratoires LCTproduction and structured small debitage methods in Olduvai arealso concurrent

It has been argued (eg Gowlett 1986 de la Torre 2008) thatthe mere presence of handaxes irrespective of their frequency isindicative of the Acheulean character of the assemblage and that ifhandaxes are absent in lt16 Ma assemblages other proxies can besought such as the presence of structured methods of small deb-itage production (de la Torre 2009) Of course these arguments donotwork everywhere For example this paper has shown that smalldebitage systems in Gadeb were rather simple despite theirco-occurrence with LCT chaicircnes opeacuteratoires Therefore it would bean oversimplification to state that handaxe production always co-appears with structured small debitage systems For these reasonsit is the study of the overall composition of assemblages that mustlead to conclusions over the nature of technological strategiesemployed on each site Whereas in other regions such as Europethere is an overwhelming predominance of only one chaicircneopeacuteratoire that of handaxes the East African Acheulean yieldsconsistence co-occurrence of LCT and small debitage reductionsequences Only the combined study of both will explain the largeinter-assemblage variability reported in this region

It only remains to address where the Gadeb sites fit in theframework of this discussion Cultural assignment of the Gadebassemblages changed even among the original excavators Clarkand Kurashina (1976) attributed Gadeb 2B and 2C to the Devel-oped Oldowan B Gadeb 8A to the Upper Acheulean and Gadeb 8Dto the earlier Acheulean A subsequent more complete assessmentof all assemblages (Clark and Kurashina 1979a) maintained Gadeb2B and 2C as Developed Oldowan B the same techno-complex to


which Gadeb 2A 2E and 8F were also included while Gadeb 8A8D and a new assemblage Gadeb 8E were considered as Acheu-lean This classification eventually experienced some changes andwhen referring to Gadeb 8F it was stated that ldquothe presence ofa few bifaces suggests that this is an Acheulian butchery siterdquo(Clark and Kurashina 1979b 146) Gadeb 8F was subsequentlyreclassified along with Gadeb 2E as Developed Oldowan C (Clark1987) while Kurashina (1987) questioned the dubious meaning ofthe term Developed Oldowan and proposed classifying such sitesin Gadeb as simply Oldowan These authors were aware of theterminological ambiguities and Clark himself stated that despitethe nomenclature used ldquoit is increasingly apparent that anyattempt at strict separation and division into Developed Oldowanor Acheulian probably has little true significance especially ifartefact forms are activity-relatedrdquo (Assefa et al 1982 42e43)

Changes of cultural allocation by the original excavators of theGadeb assemblages reflect problems of the Developed Oldowanas a concept and difficulties in accommodating its significance inthe framework of technological change during the Early StoneAge This problem is certainly not exclusive to the Gadebassemblages For example Leakey (1975) modified the taxonomicassignment of some assemblages proposed originally as Devel-oped Oldowan to Acheulean (Leakey 1971) Chesowanja wasoriginally classified as Developed Oldowan (Harris and Gowlett1980) and then as Oldowan (Gowlett et al 1981) handaxe-freeassemblages in Peninj were considered as Oldowan (de la Torreet al 2003) and then as Acheulean (de la Torre 2009) etcEven beyond Africa techno-cultural assignment changes haveoccurred in key archaeological sequences such as lsquoUbeidiyaoriginally considered as containing both Developed Oldowan andAcheulean layers (Bar-Yosef and Goren-Inbar 1993) but whichwas recently assigned as a whole to the Acheulean (Bar-Yosef andBelfer-Cohen 2001)

This all reflects the ambiguities of the term Developed Oldowanwhich has long been criticized (Stiles 1977 1980 Gowlett 1986 dela Torre andMora 2005 Semaw et al 2009) but which is still oftenemployed in recent literature In fact and focusing solely on Gadebmost references to these assemblages have mentioned thesupposed dichotomy between Developed Oldowan and Acheuleanin this sequence (eg Stiles 1980 Isaac 1982 1984 Binford 1985Potts 1991 Schick and Toth 1994 Kyara 1999 etc) However theparticular aim of the description of Gadeb assemblages presentedin this paper has been to emphasize the existence of a technologicalbackground that is shared by all sites despite variability in typepercentages All of the Gadeb sites have similar methods of smalldebitage reduction similar types of small retouched tools andsimilar types of LCTs all exploited following a similar chaicircneopeacuteratoire According to these patterns this paper maintains thatall the Gadeb sites pertain to the same techno-complex

Isaac (1986) once proposed that the emergence of the Acheu-lean introduced two main innovations compared with theOldowan One was the addition of one further step in manufacture(ie the production of large flakes that would subsequently be usedas blanks for shaped tools) The second was the application ofpredetermined mental templates onto the shaping of artefactsleading to objects (ie handaxes) that show an overall similarmorphology In addition to Isaacrsquos (1986) traits this paper arguesfor two further innovations of the early Acheulean One is the newability to detach large flakes off huge cores a technique substan-tially more difficult than flaking small hand-held cores and thesecond is the spatial and temporal fragmentation of the life historyof LCTs for there is usually separation between quarry activitiesfaccedilonnage and usediscard of handaxes These features are clearlypresent in all the Gadeb assemblages which therefore should all beregarded as Acheulean sites

Conclusions

The aim of this paper was to present a systematic account ofsome relevant assemblages from the Gadeb sequence withparticular emphasis on those mentioned in the literature asexamples of the Developed Oldowan Although references to thesesites have been constant over the last few decades no revision ofthe actual collections had ever been published until now Followinga technological approach this study has attempted to providea detailed report of the lithic assemblages of Gadeb 2E 2B 2C 8Dand Gadeb 8F from their overall composition to the particularitiesof each stone tool category

One of the main conclusions is that in general the Gadebassemblages are biased and significantly affected by post-deposi-tional processes This affects both the proportions of lithic cate-gories which are here considered to differ from those originallynoted and the relationship between stone tools natural rocks andfossils for which an accidental co-occurrence cannot be excludedThe assemblage chronology ranges between 145 and 07 Ma but atpresent it is difficult to be more precise Clark and Kurashina (1976)emphasized the resemblances between the Gadeb 2 sites andMiddle- Upper Bed II in Olduvai while Barbetti et al (1980) esti-mated an age for Gadeb 8E at around one million years Certainlythe chronological bracket of the Gadeb sites is currently too wideand further chrono-stratigraphic work is needed to refine thesequence Nevertheless the lower and upper parts of the depositsare firmly dated (Williams et al 1979 Haileab and Brown 1994)and therefore provide a chronological framework within which tobroadly contextualize the archaeological record at Gadeb

This paper has also argued that all Gadeb assemblages containelements of two different chaicircnes opeacuteratoires one relating to smallsize debitage and the other associated with LCT production In allGadeb sites small debitage flaking is usually unstructured andindicates a prevalence of short reduction sequences Howevernearly all the assemblages studied contain very small cores thatare difficult to accommodate within rationales of functional oreconomic requirements and which also suggest that knappingskills may not have been as simple as those indicated by the shortreduction sequences evident on most cores Furthermore virtuallyall the studied sites bear variable percentages of shaped tools fromsmall retouched pieces to LCTs made on huge flakes and cobblesThese LCTs are usually minimally shaped and concepts ofsymmetry and bifaciality are found only in some handaxes and notin all assemblages The sharp break between the small debitagechaicircne opeacuteratoire and that of LCTs (for which early elements of thesequence such as large cores and waste are missing) is accompa-nied on sites such as Gadeb 8F by a continuum in the technologysize and morphology of shaped tools Indeed the Gadeb 8Fassemblage provides one of the strongest cases for specific mentaltemplates in Early Stone Age technologies due to the very partic-ular characteristics of its shaped tools

As recently pointed out (Stout et al 2010) ecological andeconomic divergences (and this paper would also include stylisticvariations) are not enough to render interpretations of multipletool-making traditions Here it is argued that only detailed studiesof complete collections (rather than the study of single variables orcategories across sites) provide sound arguments that enablediscussion and characterization of the technology of one assem-blage and its consequent comparison with other sites The patternsemerging from the adoption of this perspective indicate thatdespite the variable frequencies of tools all Gadeb sites show thesame technological background The results of the present studyindicate that the entire Gadeb series can be considered as anexample of the inter-assemblage variability existing in the Acheu-lean at the end of the Lower Pleistocene


Acknowledgements

I thank the staff of the National Museum of Ethiopia in AddisAbaba for permits to study the Gadeb collections and assistanceduring my stays at the centre between 2003 and 2009 I amthankful to Sileshi Semaw Adriaacuten Arroyo and Noemi Moraacuten fortheir support and help in the study of the Gadeb assemblages I alsothank Norah Moloney Martin J Williams and the JHE reviewers fortheir valuable comments Figs 5 7 10e15 18 19 26 27 29 and 30were drawn by Noemi Moraacuten and Figs 21 22 and 24 by BeyeneDemie

Appendix Supplementary material

Supplementary data related to this article can be found online atdoi101016jjhevol201101009

References

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Barbetti M Clark JD Williams FM Williams MAJ 1980 Palaeomagnetism andthe search for very ancient fireplaces in Africa results from a million-year-oldAcheulian site in Ethiopia Anthropologie 18 299e304

Bar-Yosef O Belfer-Cohen A 2001 From Africa to Eurasia e early dispersalsQuatern Int 75 19e28

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Bower JRF 1977 Attributes of Oldowan and lower Acheulean tools ldquotraditionrdquoand design in the early lower Palaeolithic S Afr Archaeol Bull 32 113e126

Braun DR Rogers MJ Harris JWK Walker SJ 2008 Landscape-scale variationin hominin tool use evidence from the Developed Oldowan J Hum Evol 551053e1063

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Clark JD Kurashina H 1979a Hominid occupation of the east-central Highlandsof Ethiopia in the plio-Pleistocene Nature 282 33e39

Clark JD Kurashina H 1979b An analysis of earlier stone age bifaces from Gadeb(Locality 8E) northern Bale Highlands Ethiopia S Afr Archaeol Bull 3493e109

Clark JD Williams MAJ 1978 Recent archaeological research in southeasternEthiopia (1974e1975) Ann Ethiopie 11 19e44

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Eberz GW Williams FM Williams MAJ 1988 Plio-Pleistocene volcanism andsedimentary facies changes at Gadeb prehistoric site Ethiopia Geol Rundsch77 513e527

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Texier P-J Roche H Harmand S 2006 Kokiselei 5 formation de Nachukui WestTurkana (Kenya) un teacutemoignage de la variabiliteacute ou de leacutevolution des com-portements techniques au Pleacuteistocegravene ancien 14th International Congress ofPrehistoric and Protohistoric Sciences (Universiteacute de Liegravege 2001) Preacutehistoire enAfrique Sessions Geacuteneacuterales et Posters In BAR International Series 1522Oxford pp 11e22

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The Early Stone Age lithic assemblages of Gadeb (Ethiopia) and the Developed Oldowanearly Acheulean in East Africa

Introduction


Site contexts



Results







Gadeb and the Developed Oldowanearly Acheulean debate in East Africa

Conclusions

Acknowledgements

Supplementary material

References

Figure 1 A) Location of Gadeb sites in Ethiopia B) Digital Terrain Model of the Gadeb plain with position of Localities 2 and 8 C) General stratigraphy of the Gadeb sequence(adapted from Eberz et al 1988) D) and E) Stratigraphic sequence in Locality 8 and Locality 2 (adapted from Williams et al 1979) F) and G) Localities 8 and 2 respectively in 2008(photos by the author)


Despite regular referencing to Gadeb in recent literature on theEast African Early Stone Age no revision of the lithic assemblageshas been carried out since the original studies by Clark and Kura-shina in the 1970s In fact the only systematic account of the Gadeb

assemblages (Kurashina 1978) was never published and no otherdetailed reports of the lithics were made available This paper aimsto update information about these sites through a full analysis oflithics from all the so-called Developed Oldowan assemblages














Site contexts




















Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)


Total 761 1741 561 622 580 589 433 487 179 385























Test cores e e


Total 202893 (162701) 32445 (16966)






1661 2199 e

9107 15926 121901841 20414 24382231 2345 2748141 e 151292590 2533 23244264 1387 8998357 6817 13603027 11008 12282

33219 (21835) 62629 (44804) 49370 (35728)









Results



























































N N N N N


Total 109 100 24 100 60 937a 80 100 22 100



























































































































































Conclusions






Acknowledgements




References































































































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References














Site contexts




















Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)


Total 761 1741 561 622 580 589 433 487 179 385























Test cores e e


Total 202893 (162701) 32445 (16966)






1661 2199 e

9107 15926 121901841 20414 24382231 2345 2748141 e 151292590 2533 23244264 1387 8998357 6817 13603027 11008 12282

33219 (21835) 62629 (44804) 49370 (35728)









Results



























































N N N N N


Total 109 100 24 100 60 937a 80 100 22 100



























































































































































Conclusions






Acknowledgements




References































































































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References



Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)

Thiswork

Kurashina(1978)


Total 761 1741 561 622 580 589 433 487 179 385























Test cores e e


Total 202893 (162701) 32445 (16966)






1661 2199 e

9107 15926 121901841 20414 24382231 2345 2748141 e 151292590 2533 23244264 1387 8998357 6817 13603027 11008 12282

33219 (21835) 62629 (44804) 49370 (35728)









Results



























































N N N N N


Total 109 100 24 100 60 937a 80 100 22 100



























































































































































Conclusions






Acknowledgements




References































































































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References














Test cores e e


Total 202893 (162701) 32445 (16966)






1661 2199 e

9107 15926 121901841 20414 24382231 2345 2748141 e 151292590 2533 23244264 1387 8998357 6817 13603027 11008 12282

33219 (21835) 62629 (44804) 49370 (35728)









Results



























































N N N N N


Total 109 100 24 100 60 937a 80 100 22 100



























































































































































Conclusions






Acknowledgements




References































































































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References









Results



























































N N N N N


Total 109 100 24 100 60 937a 80 100 22 100



























































































































































Conclusions






Acknowledgements




References































































































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References


















































N N N N N


Total 109 100 24 100 60 937a 80 100 22 100



























































































































































Conclusions






Acknowledgements




References































































































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References

















































































































































Conclusions






Acknowledgements




References































































































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References


Acknowledgements




References































































































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References













































Introduction


Site contexts



Results








Conclusions

Acknowledgements


References