Downloaded by Scott MacEachern on January 30 2014 Jean-Marie DatouangDjoussou Molly O’GuinnessCarlson8 David A. Scott8 * * * * Scott MacEachern iron toproduce compositeartefacts. of differentforms of the (3) and artefacts; these in used differentironsteel) of eutectoid forms (including in variability the (2) Africa; sub-Saharan in centuries five about over techniques iron-working of comparison for opportunity rare a provideregion same the in 1980s the in smelts iron of reenactments (1) ethnoarchaeological interest: of points of number a has discovery This ‘barrette’a and provenance.chain local of probablynot a and hoe local a as floor, well living as a under buried found points spear/arrow of cache a recoveredincluded ironThe millennium AD. artefacts mid-second the to ing northeastern Mandara Mountains of Cameroon, and dat- in 2008. DGB-1 is a large multi-function site located in the an interior courtyard on the DGB-1 site during fieldwork wereironrecoveredartefacts of number froma 2008, In Keywords: MandaraMountains,blacksmithing,iron technology, DGBsites,ethnoarchaeology Pavillon CharlesdeKoninck,Université Laval,Québec,QC,G1V 0A6,Canada Head Tide Archaeological ConservationLaboratory, Wiscasset, ME04578,USA Department of Art History, The CotsenInstituteof Archaeology, UniversityofCalifornia,Los Angeles, CA 90095,USA Department ofSociologyand Anthropology, BowdoinCollege,Brunswick,ME04011, USA DOI 10.3213/2191-5784-10230Published onlineMay14,2013© Africa Magna Verlag, FrankfurtM.

8 [email protected] I

n o r [email protected] Abstract A Scott MacEachern,David A. Scott,MollyO'GuinnessCarlson f e t r

C [email protected] 8 v r e s n o

a Journal of African Archaeology Vol. 11 (1), 2013, pp.39–54 [email protected] s t c E o n h t

m o r f a & Jean-MarieDatouangDjoussou t i n o a

h c r e h t , M a DGB-1S t e o l o e a r u l l I G jets composites. ob- produiredes pour qualités différentes de fers ces de utilisées dans ces objets, et (3) l’utilisation de la soudure eutectoïde) l’acier compris (y fer de qualités différentes des variabilité la (2) région, même la dans 1980 années ethnoarchéologiquecontexte les en dans réalisées fer de réduction la de réactivations aux grâce sub-saharienne Afrique en sidérurgiques techniques des environ, siècles plu- sieurs intérêts : (1) l’occasion présente rare de comparer, découverte sur cinq Cette locale. provenance de une barrette, probablement allochtone ainsi qu’une houe et maillons à chaîne qu’une ainsi d’occupation, niveau un sous enterré dépôt un constituant lance/flèche de tes après J-C. Ces objets comprenaient un ensemble de poin- millénairedeuxième du milieu du Mandara datant camerounaiset monts des nord le dans trouvant se ctionnel multifon- site grand très un DGB-1, de intérieure cour une dans jour au mis été ont fer en objets des 2008, En c I G a i l c e t A a , N l n A a n r e h t r o o l n a I G s y l s e i s

C a Résumé n a d n o o r e m : 39

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 However, there are important continuities between between continuities important are there However, who profess ignorance of the history of these structures. oral histories of the region go back 200–300 years and of Lake Chad (M south crises political and environmental interrelated) 40 MacEachern etal.2010;M of the DGB sites and the Mafa (S no explicit historical relationship between the builders farmers now occupy the area of the DGB sites. There is in the mid-15 the in intensively most utilised been have to appears 1/-2 mit of both and in different places on both sites. DGB- sites, and ritual activities were carried out on the sum- two the between and DGB-1 on occupation domestic for evidence is there known: incompletely least at or unclear, present at is complex site the of functioning in The and Zimbabwe. Great Ethiopia between Africa architecture stone indigenous of example largest the and 3 2 (Figs. hectares four mately Mafa, spokenacrossthisregion. residence’chiefly of language, ‘ruins Chadic or the in 13 porary with an occupation spanning the period from the DGB-2 are only 100 m apart, and are partially contem- Mountains of Cameroon, in Central Africa. DGB-1 and logical features on the slopes of the northern Mandara stone walls, terraces, platforms and associated archaeo- dry- of complex a forms site, DGB-2 neighbouring smaller, the with DGB-1, Cameroon. of Mountains Mandara northeastern the in located site, DGB-1 the on courtyard sunken interior an from recovered were artefacts iron of number a excavations, 2008 During larger than any of the other DGB sites (D sites DGB other the of any than larger 1 teen DGB sites have been identified to this point (Fig. first author (D tinued from 2008 until 2011 under the of direction the con - have and 2002, in began colleagues and David Nicholas by sites DGB the on Excavations selves. them- mountains the from known sites chaeological ar well-preserved of lack a of because Mountains, Mandara the around plains the in sites on undertaken were region the in investigations of archaeological the all almost recently, Until mountains. the around plains the on living communities the and populations cial and political relations between Mandara Mountain so- transforming were Basin Chad Lake southern the and slave-raiding the of irruption states predatory into the site complex’s development dates to a period when M ), but the DGB-1/DGB-2 complex is significantly significantly is complex DGB-1/DGB-2 the but ), a th c to the 17 the to Communities of Chadic-speaking Mafa terrace terrace Mafa Chadic-speaking of Communities The DGB-1/DGB-2 complex covers approxi- covers complex DGB-1/DGB-2 The E a n r e h c th 2012b). DGB stands for ‘diy-geδ for stands DGB 2012b). th a centuries AD (see below). In total, six- total, centuries In below). (see AD century AD, in a period of (probably (probably of period a in AD, century v D I a & M & c E Introduction a n r e h c a c E a a 2012a). Chronologically, n r e h c c E a n r e h c r e n r e t

1988; ), and is perhaps perhaps is and ), Journal of African Archaeology Vol. 11 (1), 2013 2012b). 2008), whose D a a v v D I D I 2008; 2008; 2008; -bay’, -bay’, S. MacEachernetal. - dara Archaeological Project in the late 1980s (D Mountains, were undertaken by members of the Man- neighbouring Plata group in the northeastern Mandara itional Mafa smelts, and one smelt associated with the 2008. Two ethnoarchaeological reconstructions of trad- in DGB-1 on found artefacts iron the of interpretation people who live in the region today is significant for our tween the builders and users of DGB-1/-2 and the Mafa of themountainlandscape. that complex would have formed an impressive feature the DGB-1/-2 site complex and the humans for whom roles through the whole period of coexistence between of the past, and they will have played important social accounts historical are they as much as present the in charters social as of thought be to need disaffiliation unusual situation: such claims of cultural affiliation or an not course of is This there. excavators as working men Mafa to according terms, Mafa in interpretable were 2008 in DGB-1 at excavated features domestic amics) and that of modern Mafa populations, and some some aspects of DGB material culture (especially cer- ( site the of summit the on (CCA), Courtyard Area tral Cen- the courtyard, interior sunken a excavated sou Djous- Datouang of direction the under researchers 2008, June–July, in site DGB-1 the on work During limitations arekeptinmind. nevertheless make the comparison worthwhile, if such 2012b). The spatial and cultural proximity in this case [ smelt Mafa 1986 the of especially (and smelts those of results The 2012a). L furnaces ethnographically known from the area (D of types different the for different be probably would shed no light upon processes of decarburization which not a straightforward issue. The latter can, for example, ments) with finished tools recovered archaeologically is graphically known iron-smelting episode (bloom frag- ethno- an of results the of comparison that course, of smelts are referred to as ‘Mafa artefacts’. We recognise, while the products of modern Mafa ethnoarchaeological DGB-1 site are therefore referred to as ‘DGB artefacts’, ies. In this article, the iron artefacts recovered from the area of sub-Saharan Africa over a period of five centur pare iron-working techniques in one narrowly delimited thus allows researchers a very rare opportunity to com- recovered fromDGB-1. artefacts iron the of characteristics the with compared M e B a c The question of potential cultural continuities be- The examination of iron artefacts from DGB-1 DGB-1 from artefacts iron of examination The é l E i a s n r e h c

1988; et al. 2010) (Fig. 3). Although relatively Archaeological context D a v D I et al. 1989; D a v D I et al. et K i l l i c 1989]) can be be can 1989]) k 1991; a D v a a D I v v & D I D I -

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 known archaeologicalsitesinthearea(redstars). Fig. 1. The DGB archaeological sites (purple stars) in the Mandara Mountains of Northern Cameroon, Africa, with other Fig. 2.TheDGB-1sitefromthenortheast. Iron Artefacts from theDGB-1Site,NorthernCameroon Journal of African Archaeology Vol. 11 (1), 2013 41

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 42 occupation surfaces, and mixed with architectural deb- the of levels the above (well levels upper in although CCA, the in excavation of levels all virtually through lar ritualactivities. evidence of meat preparation in the CCA reflects simi- the that likely quite seems it and activities, sacrificial tion are an important element in Mafa ceremonial and consump- and preparation Meat meat. of cooking the for least at used enclosures, hearth were niches these and around these niches. Our interpretation is thus that in found were earth burned and bone, animal burned un- and burned charcoal, of amounts Significant yard. a set of stone niches along the south wall of the court- included and use, their during points various at swept or cleaned either been had surfaces occupation These 3–3.5 m below the level of the surrounding platforms. approximately at horizon, cm 30–40 a over surfaces occupation multiple including sequence, stratigraphic yard wall. Excavation of the CCA revealed a complex offblocked carefully equallythen and court- a behind time, some for used built, carefully CCAwas the that of side east the on staircase a and sides northeastern two subsurface stone passageways on the western and including features, architectural significant other of number a with articulated was courtyard sunken oidal trapez- this deep), m 3x4x4.5 (approximately small Distinctive DGB-type ceramics were found found were ceramics DGB-type Distinctive Journal of African Archaeology Vol. 11 (1), 2013 S. MacEachernetal. the surrounding platforms (M platforms surrounding the of level the below m 3–3.5 between levels occupation the from others three and depth m 1.5 approximately at fill architectural from one CCA, the from obtained were dates radiocarbon Four generally. more Basin Chad Lake the to probably and sites, DGB the around region the to foreign certainly are artefacts these of Some earthenware. tin-glazed be to appears what of fragments small very two and beads, glass (probably) artefacts, two artefacts made of copper alloy, stone and iron included surfaces occupation the with associated and context primary in found materials Other CCA. surfaces above the courtyard after abandonment of the platform the from in washed probably were they ris) 43). The latter three indicate an occupation in the 16 the in occupation an indicate three latter The 43). were extracted shown in black. These artefacts were were artefacts These black. in shown extracted were 4 in drawings outline the in 6 Cons to 1 Cons labelled are they group: this of part as recovered were artefacts Six surface. occupation an below cm 5–10 of the courtyard, just adjacent to the West Passage and corner northwest the in located was artefacts iron of for theCCA. use of period the of part latest the only marked have to likely quite is this periodically, clean swept were century floors the that indications given although, AD , with the areas from which metallographic samples samples metallographic which from areas the with , In the course of excavation of the CCA, a group group a CCA, the of excavation of course the In DGB-2 sitecomplex,withthe Fig. 3.PlanoftheDGB-1/ a c E DGB-1 CCA indicated. a n r e h c 2010: 2010: al. et Figure Figure th

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 notable as well that on the three larger tanged artefacts is It purpose. that for used were they that unlikely it the head, and the angle between blade and socket make ‘hoes’, but in fact the thinness of the blade, the shape of in unclear; is artefacts latter the of function The head. shovel-shaped unusual an have pieces socketed the small enough to possibly be a large arrowhead), while is (one points spear of form general the have objects area. tanged this The in found rarely are artefacts iron tanged Large socketed. were two while tanged, were then makinguseofthesite. people the for significance some of occasion an was iron artefacts were arranged, it is likely that their burial the area (D area the DGB-2 (D DGB-2 at excavations earlier during lintel stairway a under associated sickle blade) was found in a probable cache closely a and awl possible a blade, knife a arrowhead, posits is unknown, although a group of iron objects (an de these of significance precise The location. that at cached deliberately were they that likely extremely seems it another, and one with contact in and flat laid metallurgical samplingareasindicatedasblacktriangles. the with artefacts, DGB-1 the of drawings Outline 4. Fig. and 5 Figures Four of the artefacts recovered from this cache cache this from recovered artefacts the of Four a a v v D I D I 2008: 94). Given the value of iron in in iron of value the Given 94). 2008: 2012b) and the care with which these which with care the and 2012b) 6 , these artefacts are referred to as as to referred are artefacts these , Iron Artefacts from theDGB-1Site,NorthernCameroon Journal of African Archaeology Vol. 11 (1), 2013 - higher density metal left by the smithing process and process smithing the by left metal density higher in here shown is 2) (Cons which of one images, x-ray The the objects. from matrix soil the of overburden gross the removal of mechanical the guided and format picture machine. Digital x-ray images were converted to JPEG Diagnost Digital Phillips a using radiology digital for Maine, Brunswick, in Hospital Mid-Coast to taken and soils excavation in encased while photographed When first received for conservation, the artefacts were by by a Mafa informant near the DGB-5 site (D (yet) fully functional ones. Two iron artefacts recovered not but points, weapon are artefacts three these that is not actually been formed into a point. Our interpretation does not appear to be fully finished, in that the metal has (Cons 1, 2 and 6), the distal end — that is, the ‘point’ — Stark, pers. comm. to Carlson; see also (Jean together put were links the how see to difficult is it thatextent the to woven,extremelytightly is and of unusual design: it is, first, a single loop-in-loop chain these, labelled of Cons One 8, was a conserved. piece and of loop-in-loopsampled surface, chain occupation CCAthe with association in found were artefacts iron visible especiallyinCons2. blade the of end proximal the at constriction the and large tanged artefacts, especially the blunted distal ends these with common in characteristics some have 106) characteristics notedin account, these are labelled Cons 1 – Cons 9, with their following the In analysis. metallographic for sampled farming activities. possibly having been lost or discarded in the course of occupation, Mafa early an with associated be fact in may and site, the on period DGB the post-date may 7 Cons that mind in borne be to needs it artefacts, DGB the with included is it found. Although was cache the the period of use of the occupation surface after below dates probably which thus and CCA, the of surface the recovereddepthfromapproximatelyaof below1.5m aform very similar to those of modern Mafa hoes was of hoe iron socketed a 7, Finally,Cons artefacts. iron resembleMafamodernnot does piece the form in but least, at smiths Mafa modern of capacities technical thewithin be would manufacture;Mandara9 Consof be to unlikely technique production and form of basis the on is 8 Cons cache, the in found artefacts the to contrast In artefact. the of body main the from ated separ arm shaped a by formed clasp a with barrette, a [1999: 23–27]). Cons 9 has the general morphology of In addition to the six objects in the cache, two other Thus, in total, nine artefacts from the CCA were the from artefacts nine total, in Thus, , also revealed white ridges of ridges white revealed also 8, Figure Conservation Table 1 . S t a r a k v & S & D I 2008: m i h t 43 -

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 44 shown instippleddots. F+P = ferrite areas with some pearlite. Areas morphology, of corrosion are Widmanstätten = W ferrite, = F pearlite; = P and 7. The letters added to the sections indicate the following: Fig. 5. montagnard blacksmiths( Mandara by used still tool a process, forging the in hammer boulder ridged a of use the to due probably are density in variations the that notable is It artefact. which were actually glassy slags incorporated losses, into the or holes be to thought originally areas, dark Tab. 1.Artefactsincludedintheanalysis,withlocationsCentralCourtyard Area andsampledesignation. samples from the object using a jeweller’s hand-saw hand-saw jeweller’s a using object the from samples DGB artefacts. Initially, attempts were made to remove were chosen to contrast blade edges spots with handlesSampling on the MacEachern. by reviewed/approved and Scott, and Carlson by designed was analysis ition Cons 9 Cons 8 Cons 7 Cons 6 Cons 5 Cons 4 Cons 3 Cons 2 Cons 1 Artefact A sampling scheme for metallurgical and compos- Drawing showing remaining iron content in Cons 5, 6 R o ‘Barrette’ Loop-in-loop chain Mafa-style hoe Tanged point-spear Socketed artefactwithblade Tanged point-arrow Socketed artefactwithblade Tanged point-spear Tanged point-spear Descriptor b n o s t r e 2012). Journal of African Archaeology Vol. 11 (1), 2013 S. MacEachernetal. shown instippleddots. F+P = ferrite areas with some pearlite. Areas of corrosion are ing: P = pearlite; F = ferrite, W = Widmanstätten morphology, 6 and 9. The letters added to the sections indicate the follow- Fig. 6. done under stereomicroscopy. The sandy was quartz grains cleaning All needle. vibrating #3 ® Tool Paleo a and psi), 10–80 size, particle micron (17.5–28 late cleaning using dolomite and aluminium oxide particu- micro-abrasive driven air compressed cleaning, hand including techniques, of variety a using done was ing clean- mechanical Final place. in were when fills white the again and sampling, after and during before, photography digital with documented fully were sites Sample length. in side per mm 3–5 were that samples triangular remove to used successfully was discs tion separa- with tool way.dremel this Arotary cut be to hard too proved iron DGB the but blades, 00 size and CCA-NE-302bd CCA-EWall-290bd CCA-160bd CCA-NW-313-321bd CCA-NW-313-320bd CCA-NW-313-320bd CCA-NW-313-319bd CCA-NW-313-318bd CCA-NW-313-317bd Location Drawings of the remaining metallic areas for Cons 3, Cons 9Barrette Cons 8Chain Cons 7Blade Cons 7Socket Cons 6 Tang Cons 5Blade Cons 4Point Cons 3Head Cons 2Point Cons 1Blade Samples

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 with over 10 ppm Cl ppm 10 over with Objects treatment. extraction chloride from cleared separate 0.5M sodium hydroxide solutions for one one (Cl chloride determine to for month solutions hydroxide sodium 0.5M separate risk theobject. sandy corrosion matrix the leave to made was decision the MacEachern, with consultation after and, form artefact’s the of loss the risk could cleaning Over-zealous object. the of shape the retains that layer corrosion this is it as objects, the from removed be totally not could soil local the from Samples were prepared, artefacts. mounted, the ground and of polished microstructure original the of none preserved and corroded completely were few a while substantial amounts of the original metallic constituents if heavily corroded, and most of the artefacts preserved even iron, residual some contained Most samples. the of microstructure and composition the analyzed Scott was anorange-black. retained corrosion products, the color with tannic acid still surface the Where black. colour surface object’s face from renewed corrosion. This left the metallic iron stabilizing treatment were used to protect the iron sur- location ofthefills. were photographed before in-painting to document the areas fill Milliput® object’s Each removed. be to fill the for allows and polymer ® B-72 the releases which then acetone, with fills the wetting by removable are object. fills surrounding These the of colour the to repair the blend to paints artist’s acrylic with painted later, it was sanded and carved into the final shape and were set into the voids. When this putty dried 24 hours grade) (fine ® Milliput called epoxy 2-part grade tion conserva- a of made fills before acetone % in ® 10 B-72 with sealed edges inner their had voids pling sam- Metallurgical acetone. in dissolved co-polymer) methacrylate ethyl an (chemically ® B-72 % 10–20 and air-dried. constant, was 7.0 of pH until water deionised cooled washed of the sodium hydroxide solution in boiled and than 30 ppm extracted in 2 months time. Objects were less average on small, very was objects iron these in calibrated to reference standards.ion The chloride ion chloride load and analyzer 407A Orion an and tested again. Testing of the solution was done using that returned 10 ppm Cl All iron objects except Cons 7 were placed into into placed were 7 Cons except objects iron All Several coats of a 5 % w/v tannic acid surface surface acid tannic w/v % 5 a of coats Several Areas of loose chips of iron were reattached using Metallographic examination - were left to soak another month another soak to left were in situ when its removal would - or less in a month’s time were - ) ion loads. ion ) Artefacts Iron Artefacts from theDGB-1Site,NorthernCameroon Journal of African Archaeology Vol. 11 (1), 2013 3 2 Widmanstätten morphology following by etching (S etching by following extent of the pearlite shows that the carbon content carbon the that shows pearlite the of extent The steel. carbon welded-on the in grains ferrite and pearlitethe shows 7 in Figure microstructure etched The together. parts two the weld to here been has undertaken forging heavy that suggests and variable, very is steel the of region the in structure grain The 7 overall view at low magnification is shown in The inclusions. slag darker of series a by delineated is weld the of line The welded. been has steel carbon a which onto blade low-carbon a of consisting ture, microstruc- interesting an shows section blade This sion crust. corro- the within grains iron the of shape of retention iron artefacts from this site, there is no pseudomorphic the in dots: stippled in shown are corrosion of Areas of the steel, at which the carbon content rises to 0.8%. constituent eutectoid the pearlite, some with ferrite of 1 indicate the following: P = pearlite P= following: the indicate 5 (Figs. study mount ofthemetallograph. F the on mounted camera digital D300 Nikon a using using a Nikon Epiphot metallograph and photographed , etched in 2 % nital to reveal the grain structure. grain the reveal to nital % 2 in etched , cycles. common in early iron and steels because of heating and cooling quite This Widmanstättendown. is cooled precipitation steel or iron the as boundaries, grain former on grow ferrite imntte morphology: Widmanstätten visible inthecrystals. components internal without coloured, lightly or white appears forge and hammering. rapidly a Widmanstätten structurecouldresult. less cooled if but steels, in phase hard very a , create cooling his iron hoe in water. ments present. ele- alloying no with iron otherwise or iron, Wrought Ferrite: then thecarboncontentisabout0.4%overall. microstructure is composed of pearlite and the other half ferrite, about 0.8 % carbon and consists entirely of pearlite. If half of the content. carbon the of indication good a is present pearlite of amount The nital. in colour straw-yellow a etch may and particles, small very of cluster darker or phase heat before striking. red to iron the heating by produces blacksmith the what is iron in which austenite, from transition to-solid compound Fe intermetallic hard (the cementite and ferrite of mixture fine is a pearlite iron, bloomery of constituent common A Pearlite: In sketches of some of the samples mounted for for mounted samples the of some of sketches In In Descriptions ofindividualartefacts D a 3 v

C). Pearlite is produced through a eutectoid solid- and Ferrite is soft and easily worked, by heating in the D I In etched sections, the pearlite appears as a dark & L ), the letters added to the sections the to added letters the 6), e Cons 1Blade

In the photomicrographs, ferrite generally B é l i t t o c s (1988), Dokwaza is shown quickly

If very quickly cooled, this could In low-carbon steels, needles of of needles steels, low-carbon In 3 ; while F+P indicates areas 1991, 2011), examined examined 2011), 1991, 1

; F = ferrite = F ; An eutectoid steel has steel eutectoid An Figure Figure 2 ; W = W; 45

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 46 ferritic back. soft a on blade steel a create to method used monly com- a is blade a of back the along edge steel a of welding-on The %. 0.6 about is content carbon the where edge, the along welded steel carbon the with contrasts This purpose. this for selected was ferrite tively low slag content, suggesting that a quite pure rite area of the blade is free of carbon and has a rela- rises to about 0.6 % in this area of the blade. The fer the upperblade. of area dark the in slags glassy contains and corroded tially differen-inhomogeneous, very is iron length. The the along features elongated with blade the of microstructure striated 8. Fig. Cons 2 tanged point: the x-radiograph shows the the shows x-radiograph the point: tanged 2 Cons Journal of African Archaeology Vol. 11 (1), 2013 S. MacEachernetal. - rounded. Ferrite grains are large and clear, with no no inclusions. with clear, and large are grains Ferrite rounded. in shown as content carbon no with iron wrought a rite, fer pure quite a in made to was artefact this that enough show is it but section, corroded heavily rather this in remaining metal of areas two only are There steel andlow-carboniron,asinCons1. eutectoid of areas between weld a indicate may section in some areas to close to 0.8 %. The characteristicsjagged single-phase glassy slag. The carbon content rises of this ratherphaseaseen,slagtheslag isbemostcanbutof spear, as visible in amount of a glassy slag elongated along the length of the contentdropping toabout 0.3%. Theresubstantialisa ferritemorepearlite,lessothersandandofcarbon the steeleutectoid of areas some with heterogeneousiron quite a shows therefore section The carbon. less little a and laths ferrite more contains section the of side other of the section, the grains become very fine pearlite. The mid-point the to along Passing pearlite. less and ferrite tion. Towards the other side of the section, there is precipita- Widmanstättenmorea with structure pearlite and Figure 9 shows, towards one end of the section, a ferrite here is about 0.6 %. The overall picture of the section incontent carbon The pearlite. the than volume smaller a of the spear. This pro-eutectoid ferrite is jagged and has seen,showing thatcarbon a steel hasbeen used inpart be boundariescan grain the atferrite acicularwith ite pearl- fine very artefact, the of region one In 9. Figure in shown is photomicrograph spear.representative A 8 in shown is point spear the of x-radiograph An and reveals the heavily striated iron used to make the Figure 11 . The slag inclusions are glassy and rather Cons 3Socketedartefact Figure 10. In some of the iron, a two- Cons 2Blade to theprincipallyferriteback. steel edge, which has been welded carbon the showing nital, % 2 in Fig. 7. Cons 1 tanged point, etched Figure -

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 Iron Artefacts from theDGB-1Site,NorthernCameroon Journal of African Archaeology Vol. 11 (1), 2013 carbon content. no with ferrite of structure grain a and inclusions slag glassy of ter scat- showing nital, % 2 in etched 11.Fig. er partofthephotomicrograph. grains rapidly decreases in the low- the of content carbon seen.The be can weld possible a across sions fication image, the long slag inclu- higher-magni- this In nital. % 2 in Fig. 10. Cons 2 tanged point, etched of Figure10. red rectangle indicates the location iron, with low carbon content. The of piece different a is part lower the and steel, eutectoid a nearly is here alloy the that shows graph photomicro- the of part upper the to area pearlitic The nital. % 2 in Fig. 9. Cons 2 tanged point, etched Cons 3 socketed artefact, socketed 3 Cons 47

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 48 type seen in much ancient iron: a two-phase mixture mixture two-phase a iron: ancient much in seen type predominantlyare of ferrite. Thegrains slag here the is of a common section, the of end one In inclusions. slag thin elongated heavily long, shows section The for anarrowheadtobemadeofalow-carbonsteel. reason no is there as knives, and blades for bloom the if the were selecting the carbon steel bits of iron with no carbon content. This would be quite likely ence would be that the arrowhead was made in a ferritic infer-the clues, remaining few the From of. consisted ture of the original iron that constituted this arrowhead the basis of this section, to decide what the microstruc- flakes of metallic iron remaining. It is quite tiny difficult, few on a only with corroded, totally is sample This Cons 5Socketedartefact Cons 4 Arrow point Journal of African Archaeology Vol. 11 (1), 2013 S. MacEachernetal. in quite clean ferrite, with little slag content, as illustrated The microstructure shows that the tang is composed of carbon insomeareas. low-carbon steel component, with some ferrite and littlea of made been has it that and shape to hot-forged ily heav- been has artefact this that shows evidence The boundaries. grain austenite former on grains ferrite ically Widmanstätten precipitation of the pro-eutectoid ferrite grains are revealed in in seen as %, 0.5 to rises content carbon the areas, some In fluctuate. content carbon and size grain the and even, not is but creases in- section the of region central the in content carbon of a glassy matrix with wüstite particles within it. The . The slag is comprised of a two-phased two-phased a of comprised is slag The 14. Figure Cons 6 Tang size of the grains may possibly is no carbon content at all. The grains are very large, and there tang was moderate. The ferrite the of part this of hot-forging of amount the that infer can we tang, the of deformation of extent the From 5. Cons in as mixture, wüstite and glass gation asaresultofhot-forging. slag content shows extensive elon and area, this in low is content carbon The nital. % 2 in etched Fig. 13. Cons 5 socketed artefact, carbon contentismuchlower. regionwherethea artefact in but with there is little slag content. Contrast carbon content is about 0.4 % and The seen. is steel low-carbon the of structure Widmanstätten the area, this In nital. % 2 in etched Cons12. socketed5Fig. artefact, , while the pure pure the while 12, Figure Figure 13. There is a typ- , from the same same the from 13, Figure -

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 of another piece of steel, as is obvious from welding the than rather product bloomery the in bution low-carbon steel region suggests inhomogeneous distri- carbon content to one side. The gradual transition to the hot-forged to shape, is considerably harder, and has some heavily been has blade the while ferrite, soft quite a in F to about 0.1–0.2 %. This low-carbon steel is illustrated in Towardsthe edge of the blade, the carbon content rises with phosphorus canbeseen. associated often ‘ghosting’ any of sign no but be due to other alloying elements such as phosphorus, the caseofCons1tanged point. igure 15. The investigation shows that the tang is made Cons 6Blade Iron Artefacts from theDGB-1Site,NorthernCameroon Journal of African Archaeology Vol. 11 (1), 2013 Figure 7 in in the section in a fairly uniform manner, with the ferrite iron. of length the along ferrite-pearlitecontinues The this in stringers slag small numerous and unusual are to the boundary of the change in carbon content. There close present, slag glassy two-phased the of inclusion slag thick a is there although two, the between weld of the section being practically ferrite with no obvious ing along one side to about 0.3 % carbon, the other side increases along the length of the section, gradually slowly ris- content carbon The inclusions. slag small of scatter large a with ferrite mostly carbon, low of area in seen areas. As different in considerable variations in the amount of carbon to presentdue microstructure, interesting an has socket This Cons 7Socket this areaoftheartefact. in content slag little with steel, low-carbon a of that is structure (blade), etched in 2 % nital. The point tanged 6 Cons 15. Fig. the corrosioncrustisevident. with junction The ferrite. pure The grains are large and of quite (tang), etched in 2 % nital, x280. 14. Fig. , there is one one is there 16, Figure Cons 6 tanged point point tanged 6 Cons 49

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 50 back oftheblade. has been selected for this blade, with ferrite towards the slag is present. The evidence suggests that a steel edge wüstite and glassytwo-phased the of amountA small ingmostly ferrite and further back still, to pure ferrite. Towards one edge, the carbon content falls back to be- carbon. % 0.4–0.5 about with ferrite and pearlite of content and moving back from this edge, the grains are section shows a fine pearlite eutectoid, of 0.8 % carbon been selected for this part of the has artefact. steel The carbon end of medium the a that indicates 17, Figure in shown section, blade the of photomicrograph The towards thethickerpartofsection. section the of sides the of one to confined being area Cons 7Blade Journal of African Archaeology Vol. 11 (1), 2013 S. MacEachernetal. facts from the DGB-1 site. site. DGB-1 the from facts arte- other the of some in used than content carbon less with iron, wrought soft a with than steel carbon would be much more difficult in a high- or moderate- loops the Forming iron. wrought soft for use good been a is has which chain, loop-in-loop this make to selected iron soft a that show shape and size their and grains The slag. wüstite and glassy two-phase in shown is microstructure The carbides. or nitrides grain nal inter from possibly grains, the within sub-structure little a with polygonal and size even of ferrite, pure low,very is content ofessentially are grains the and of remnant metal is exposed on polishing. The carbon region a small only and corroded, is very section The . There is a small scatter of the the of scatter small a is There 18. Figure Cons 8Loop-in-loopchain the photomicrograph.x80. of region lower the in located is that steel eutectoid the to ferrite carbon lower the from transition the showing nital, % 2 in etched (blade), hoe 7 Cons 17. Fig. refined grainsize. moderated a and content carbon low-carbon steel with about 0.2 % the showing nital, % 2 in etched 16. Fig. Cons 7 hoe (socket), (socket), hoe 7 Cons -

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 region (Cons 1–7) and those that on stylistic grounds stylistic on that those and 1–7) (Cons region Mandara the in produced been have be to assumed the from artefacts the between similarities artefacts reveals site DGB-1 iron of group this on Research glassy slagswithwüstite. 0.2 % carbon. The slag about inclusions are with small, two-phase pearlite, and ferrite has and morphology Widmanstättenmore in is structure the side, other the in shown as pearlite, little a with ferrite of region a into grades which ferrite, mostly is section the surface, outer the towards area one In This artefact is principally made of a low-carbon steel. Metallographic conclusions Cons 9Barrette . Towards19. Figure Iron Artefacts from theDGB-1Site,NorthernCameroon Journal of African Archaeology Vol. 11 (1), 2013 of steel would be unnecessary or counterproductive, counterproductive, or unnecessary be would steel of group of artefacts. For those objects where this the in presence demonstrated is content, carbon variable with of different elements, some with no carbon and others welding of use The site.) the of use post-DGB a from possibly on Cons 2. (As noted above, Cons 7 may come and blades, 7 Cons and 1 Cons the on as such cutting, steel for making harder components of blades used for of use sophisticated the shows iron ferritic welded to applied components steel low-carbon of use lective with Widmanstättencarbon % 0.2–0.4 se- ferrite. The variety of materials of lesser carbon content, typically steel available to them with about 0.8 % carbon, and a eutectoid had metalsmiths DGB-1 The below). (see groups both in wüstite with slags glassy of two-phase appearance the in especially 8–9), (Cons region the outside produced been have to hypothesised are small andeveninsize. are grains ferrite The content. slag little relatively ferrite with grains showing nital, % 2 in Fig. 19. 0.1-0.2 %.x130 about is content carbon overall ite among the ferrite grains. The pearl grey of islands small ing chain, etched in 2 % nital, show- loop-in-loop 8 Cons 18. Fig. Cons 9 ‘Barrette’, etched 51 -

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 a film (D film a of subject the became that 1986 in smelt traditional a reenacting documented was Dokwaza smith Mafa The been observed by 52 content (S content than those produced in Medieval Europe, with less slag ferrous materials overall are typically of higher quality encountered in bloomerycommonly ironvery production. slag, However,type the wüstite and glass phased two- a or glassy either are slags the and products iron bloomery European typical of that to comparable ally others of relatively pure iron. The slag content is gener and steel low-carbon of were regions some which in jects shows the heterogeneous nature of the iron bloom, difference intheirfunction. tanged blades, presumably because of some (unknown) high priority for the socketed artefacts as it was for the suggests that edge hardness may not have been such a while Cons 5 has a highly variable carbon content. This the Cons 1 and 7 blades; Cons 3 is almost pure ferrite, to contrast in especially striking, is artefacts socketed low carbon content. The variable carbon content of the very with iron softer selected artefacts the produced such as the Cons 8 loop-in-loop chain, the smiths who V the 1986 smelt by smelt 1986 the of products the of analysis further with and 1989 in furnace, going downwards into the furnace and oper and furnace the into downwards furnace,going with a long tuyère that is suspended from the roof of the smelting furnaces are remarkable for their construction, M of high-qualitysteelblades. could then be used for specific purposes in the making parts These harder. noticeably as blacksmith skilled the to themselves reveal would bloom iron the from offbroken or removed prills small of hammering The utilised by the DGB-1 people in their iron technology. selectively were but produced, only not were position examination has confirmed thatThe steels of eutectoid com purposes. selected for available were materials high-quality some that showing 1, Cons and 7 Cons of blades the in as inclusions, slag no practically have among Sukur, Marghi and Plata smiths (S ticularly well known, but observations were also made par is group Mafa the of blacksmiths by working Iron colonial and post-colonial iron working is well attested. iron artefacts from northern Cameroon, in an area where paper describes the metallurgical characteristics of some rican iron-smelting technologies is well known ( The sophistication of the many different indigenous Af- a e w r e u g Variation in carbon content across some of the ob- h a Comparison ofDGB-1artefactswith 1980; A n ethnoarchaeological Mafaexamples 1973; a t t o c v D I & L 1991). Some of the low-carbon steels steels low-carbon the of Some 1991). u m e r D H a D e i v B n a 2004; K D I d v é l l r e 1995). Mafa iron smelting has smelting iron Mafa 1995). D I i

s (1989). The Mafa iron- Mafa (1989). The al. et i 1988), with a second smelt second a with 1988), n g (1955) and i l l i c k 2009). The present Journal of African Archaeology Vol. 11 (1), 2013 G a a n o o s s r I D (1954). v a 1964; S. MacEachernetal. n

d r e - - - -

varying from 0.2 % to 0.8 % (D content carbon a had product finished a as example, for Dokwaza, by made hoe A purposes. specific for iron of types different selecting in smiths Mafa the of skill the with associated is and examples, logical ethnoarchaeo the in found microstructures of range steel components used and by the Mafa is iron well illustrated by the the of quality high The welding. and hammering by them from artefact iron an fabricate to order in decarburised become to have would iron cast effectively are that bloom the from pieces those iron, heterogeneous such of smithing the In earlier. years 500 some artefacts DGB-1 the in found iron/steel of variety the with comparable closely is heterogeneity cast iron, representing a carbon content over 2 %. This of areas mixed (4) and carbon; of % 1 about with steel, high-carbon (3) carbon; % 0.2 about with (ferrite) iron wrought (1) were: smelt Dokwaza 1986 sitting overthefurnace. effectively is who smith, the by bellows hand by ated excavations at from DGB-1 suggests that their recovered iron-working artefacts the of Examination times. modern in blacksmiths Mafa of those and techniques and allows for comparison between their metallurgical cupiers of the DGB sites approximately 500 years ago, tion of ferrous materials utilised by the prehistoric oc- This study provides insights into the quality and selec- where softerironwasrequiredfortheirfabrication. 9) and 8 (Cons artefacts imported possibly the in and Cons 4 and 6), in the socketed artefacts (Cons 3 and 5), example (for premium a such at be not would hardness use of softer iron for tangs and arrowheads, areas where utility. Analysis of the DGB-1 artefacts also revealed thewasitboth recognised andappreciated foritspractical on the selective use of this high-quality product and that awelded edge (Cons 1) revealed that value was placed carbonsteelas 0.5–0.6% a ofsite. usetheThe of use earlierfromanMafaphasebe ofturned to out Cons7 observed here. This would be significantly interesting if betweensome of the Dokwaza iron products and those similarity the confirming content, carbon % 0.8 about throughout,steelofmadeuniform withandisblade 7 from the DGB-1 artefacts all made use of steel.hoe (ConsThe 7) was Consof a medium-carbon steel. The blades the while iron, wrought of made be to determined was 0.1 %toabout%. below of content carbon a had region the in also smelted iron from example older made locally a while

The documented ferrous materials produced in the One of the socketed artefacts (Cons 3) from DGB-1 less than 0.05 % carbon; (2) low-carbon steel, with Conclusion a v D I et al. 1989: 199), white and grey and white -

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 like to thank the various members of his field crews crews field his of members various the thank to like would MacEachern College. Bowdoin and Society, 92-1860 and 410-95-0379), the National Geographic Grants 410-83-0819, 410-85-1040, 410-88-0361, 410- (Research Canada of Council Research Humanities and Sciences Social the # 0743058), Grant (Research Foundation Science the National from grants through supported been has paper this behind research The dara Mountains. between these past and present inhabitants of the Man- some degree of cultural and historical continuity exists narratives, historical own their within sites DGB the that, although modern Mafa people do not incorporate in these different cases. They thus make it more likely tions that appear in technological and material contexts inhabit the same area, one of a number of such connec- of the DGB sites and the modern populations that now culturalof connection between strand the prehistoric inhabitantsanother as themselves establish identified have we that similarities general the hand, other the generally similar smelting and forging techniques. On Central of part this in traditions of use making Africa, fied are ones that might also hold for other iron-working working traditions. The similarities that we have identi- iron- Mafa modern and DGB the between continuity sons, make a claim for direct technological or cultural artefacts inwhichmalleabilitywasimportant. content could easily be due to selection of soft iron for metallurgy,their on based carbon low very their artefacts since DGB from distinguished be easily cannot region the to foreign likely quite are morphology, on cess. It is also notable that the two artefacts that, based pro- conservation the during difficult sampling made and hardness, just as the hardness of the DGB artefacts iron products were superior to Western tools in strength useful. Mafa and other Mandara peoples claim that their the varying qualities of these materials would be most where — blades especially — artefacts the of areas in welding through steel and iron of kinds different ing combin- in and appropriate; most be would qualities in making use of them in artefacts where their different differentthese processing and steel; and iron of forms selecting in sophistication: technological impressive demonstrated smiths DGB The use. for then decarburised was iron cast this that but smelts, Mafa 1980s the in were they as blooms, these in produced been have also would iron cast that likely quite is It iron. steel, various forms of lower-carbon steel, and wrought eutectoid yielding blooms with procedures, smelting traditional reconstructing smiths Mafa by produced techniques produced ferrous materials similar to those We cannot, on the sole basis of these compari these of basis sole the on Wecannot, Acknowledgements Iron Artefacts from theDGB-1Site,NorthernCameroon Journal of African Archaeology Vol. 11 (1), 2013 - Killick, D. 2009. Cairo to Cape: the spread of metallurgy through recent of 1991. relevance D. The Killick, iron-smelting African in Eisenverarbeitung und Schmelzöfen 1955. P. Hinderling, 1954. R. Gardi, David, N. & MacEachern, S. 1988. The Mandara Archaeological David, N. & Le Bléis, Y. 1988. Be- 1989. R. Heimann, & Wayman,D., M. Killick, N., David, David, N. 2012b. Ricardo in the Mandara Mountains: iron, com- David, N. 2012a. Introduction. In: David, N. (ed.), N. David, In: Introduction. 2012a. N. David, David, N. 2008. N. David, loop chain. loop-in- single the of form the interpreting for Stark Jean to and objects, the sample to studio his of use the for McCreight Timto also Thanks equipment. radiology digital their of use for Maine Brunswick, and Quill the staff department radiology of Hospital, Mid-Coast Paul Mr. to thanks Many sites. DGB on the seasons field 2010-2011 and 2008 2007, the for David, N. 1995. from contribution a Africa: in roads Iron 2004. D.A. 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Reports, Archaeological British Cameroon . Northern of Media, UniversityofCalgary, Calgary. Communications of Department working. iron African in UNESCO, Paris,pp.149–164. in Africa. New Light on its Antiquity: West and Central . Africa Nigeria. In: Bocoum, H. (ed.), Black Hephaistos: exploring culture and science . Privately printed, printed, Privately Hephastus. schwarze Der Performance and Agency: The DGB Sites Sites DGB The Agency: and Performance References Recent Advances in Archaeometal- in Advances Recent Le milieu et les hommes: recherches Dokwaza, last of the African iron- Journal of World Prehistory 22 (4), African ArchaeologicalAfrican Review The Origins of Iron Metallurgy 75,1263–1266. Metals in Metals 53

Downloaded by Scott MacEachern on January 30 2014 Downloaded by Scott MacEachern on January 30 2014 54 aso, . 94 Io-mlig n h hl vlae f Sukur, of village hill the in Iron-smelting 1964. H. Sassoon, and hoes iron ethnicity: and style, Form, 2012. I. Robertson, 2010. R. Janson, & J.-M. Djoussou, Datouang S., MacEachern, MacEachern, S. 2012b. Wandala and the DGB sites: political cen- the of history early and prehistory The 2012a. S. MacEachern, org/10.2307/2796575 Nigeria. north-eastern Africa World Press,Trenton, pp.185–223. N. (ed.), knives in the Mandara region, Northern Cameroon. In: David, Akuma 73,37–45. 2008. Cameroon, northern DGB-1, at Excavations 272–287. http://dx.doi.org/10.1080/0067270X.2012.707480 Cameroon. tralisation and its alternatives north of the Mandara Mountains, Culture. Africa World Press,Trenton, pp.29–67. (ed.), N. David, In: plains. surrounding and Mountains Mandara northern Metals Metals in Mandara Mountains’ Society and Culture. Azania: Archaeological Research in Africa 47 (3), Metals in Mandara Mountains’Mandara in Metals and Society 64, 174–178. http://dx.doi. 174–178. 64, Man Journal of African Archaeology Vol. 11 (1), 2013 Nyame Nyame S. MacEachernetal. Vaughan, J.H. 1973. Enkyagu as artists in Marghi society. In: society. Marghi in artists as Enkyagu 1973. Vaughan,J.H. in iron of 1980. advent N. The Merwe, In: der Africa. Wer-van of constructions indigenous Representations: 2008. J. Sterner, 1999. J. Smith, & J. Stark, Scott, D. 1991. D. Scott, Scott, D. 2011. ciety d’Azavado, W.L. (ed.), 463–506. Press , University YaleIron. Muhly,(eds.), & J.D. M.A. time, pp. 119–123. Archaeopress, Cameroon. Northern of Sites DGB (ed.), N. David, In: past. the Their Derivatives CSP Press,Los Angeles. and HistoricMetals.GettyPress,Los Angeles. . IndianaUniversityPress,Bloomington,pp.162–193. Ancient Metals: Metallurgy and Microstructure. Metallography and Microstructure of Ancient of Microstructure and Metallography . Brynmorgen Press,Portland,Maine. The Traditional Artist in African So- Classical Loop-in-Loop Chains and Chains Loop-in-Loop Classical Performance and Agency: The Agency: and Performance New Haven and London, pp. pp. London, and Haven New The Coming of the Age of Age the of Coming The Oxford, Oxford,

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