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ROCEEDINGSCTESA 2006THNTERNTIONYMOSI
ROCEEDINGSCTESA 2006THNTERNTIONYMOSIUM ONRCHEOMETRY36EYMOSIUMNTERNTIONRCHÉOMETRIEUEBECITYJean-François Moreau, Réginald AugerJacques Chabot et Anja HerzogOrganizing InstitutionsCELAT, Université Laval, Cahiers d’archéologie du CELAT, nATI ICATION OF MELTI LATEAERRETV. ERNEELS1. INAAIMBloom smelting in West Africa has a long tradition dating back to the second half of the second millennium BC (Bocoum 2002). By the time colonial iron replaced the indigenous production around

the end of the 19 century, this craft ha
the end of the 19 century, this craft had locally developed into a major industry (de Barros 1986; Warnier & Fowler 1979) with an outstanding technological variability (Killick 1991).The Dogon Plateau, located in Mali at the margin of the interior delta of the Niger, is well known for its rich traditions and a remarkable material culture. Until recently however, the knowledge of the Dogon iron metallurgy was restricted to the eastern border of the Plateau (Martinelli 1993).Within the framework of the inte

rdisciplinary and international research
rdisciplinary and international research program “Human population and palaeo-environment in West Africa” (Huysecom 2002), an ongoing research project aims to understand the development of iron production on the Dogon Plateau. It appears that there are numerous remains of iron production, showing a large variability in furnace design and waste 1.Annual reports of these investigations are published in the series «Jahresbericht SLSA. Zurich and Vaduz: CONTENTS454ROCEEDINGSOFTHETHNTERNTIONY

MOSIUMONRCHEOMETRYassemblage, and at le
MOSIUMONRCHEOMETRYassemblage, and at least six groups could be differentiated based on these remains. In this paper, we present the smelting site of Fiko (6 C. AD), which has been investigated by archaeological and archaeometric methods. The metallurgical remains are discussed, and the iron production 2. ARFiko is located at the western margin of the Dogon Plateau, between Mopti and Bandiagara, a few kilometres from the Yame River. The smelting site is situated at the foot of a sandstone promontory do

minated by the ancient village of Fiko.
minated by the ancient village of Fiko. Some huge crater-shaped slag dumps, up to 200-m long and 7-m high, testify of large scale metallurgy (Fig. 1).Two production periods can be distinguished. The �rst smelters established the metallurgical site on the terraces. A series of �ve 14C accelerator dates from strati�ed charcoal samples shows these early activities may have started as early as the 5 or 6 century AD and lasted there until the century. Then, the smelting activi

ties shifted to the �elds bel
ties shifted to the �elds below, where they remained until the 1900 AD, when the European iron became widely available.2.1475+/-50 BP (ETH-29679), 925+-50 BP (ETH-31123), 675+/-45 BP (ETH-29678), 625+/-45 BP (ETH-28032), 475+-50 BP (ETH-31122). igure 1. Panoramic view on the large slag dumps of Fiko. The slag dump on the left is 200-m long. The early smelters c. AD cal.) were established on the sandstone terraces, later the production was displaced to the �elds below (in activit

y until about 1900 AD).CONTENTS455ECH
y until about 1900 AD).CONTENTS455ECHNOLOGICCTERISTIONNDNTIFICTIONOFRGELERONMELTINGITEINIKOThe interior area of a slag dump crater from the later periodhas been entirely excavated. It yielded two huge twin smelting furnaces which no doubt where still active around 1900 AD. They consist of a bathtub-shaped pit dug into the soil with a clay lining incorporating small slag fragments and sometimes a straw temper, and a superstructure made of slags and clay. The pit was originally about 120 cm deep. In fr

ont of the furnaces, a cavity gave acces
ont of the furnaces, a cavity gave access to the front door. The shaft has collapsed in Fiko, but a similar and well preserved furnace has been excavated on the nearby site of Kema. An extrapolation of the available data suggests a shaft height of about 150cm. The tuyères were positioned all around the furnace through approximately 25 apertures just above the pit. The internal chamber is about 250 x 175 cm large at tuyère height, and the volume is estimated to about 4.5m. The furnace lining is nearl

y unaffected by slagging, attesting of l
y unaffected by slagging, attesting of low temperatures outside of the hot spot. The furnace worked by natural draft.The metallurgical waste was discarded immediately around the furnaces, the tuyères mainly behind and the slag in front of the furnaces, such as to form a regular pattern of the different metallurgical residues visible on many of the craters. To keep the working area clean, sustaining walls up to two metres high were built successively from large slag blocks on the furnace perimeters. This

characteristic organisation of work and
characteristic organisation of work and space is found on all sites of this technological 3. TATIRepresentative samples of the different slag types, oresand furnace material were collected on the smelting sites. Semi-quantitative bulk chemical analyses of these materials were obtained by X-ray �uorescence (XRF) spectrometry (Uniquant analysis program). The chemical compositions presented in this paper are standardised to 100 on an anhydrous base; the standard is calculated on FeO for the slag

s and on Fe for the other samples. Forty
s and on Fe for the other samples. Forty-four thin and polished thin sections were examined by optical microscopy and with an L30 Sirion FEG electron scanning microscope (SEM). Energy-dispersive -ray (ED) analysis with an EDA spectrometer was used to deterThe examination of the metallurgical waste products, in the �eld and in the laboratory, led to tuyères have an external diameter of less than 10 cm. The recovered tuyères are heavily fused on the part protruding into the furnace. They co

ntain large quantities of quartz sand (3
ntain large quantities of quartz sand (35-50and large amounts of straw are incorporated. These materials are very high in silica (mean SiO 81.1 wt %), and they contain large amounts of aluminium (AlCONTENTS456ROCEEDINGSOFTHETHNTERNTIONYMOSIUMONRCHEOMETRYigure 2. The main metallurgical remains and their position in the smelting furnace of Fiko. The shaft is reconstructed from data obtained on the nearby smelting site of Kema. The bloom is from the neighboring village of Kakoli (photograph CONTENTS