Thesis submitted to the University of London for the Degree of Doctor of Philosophy

348 Pages·2013·23.86 MB·English

Iron Production in Iron Age Zimbabwe:
Stagnation or Innovation?
Shadreck Chirikure
Thesis submitted to the University of London for the
Degree of Doctor of Philosophy
Institute of Archaeology
University College London
August 2005
UMI Number: U591878
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Abstract
In conventional reconstructions of southern African archaeology, it has been assumed
implicitly or explicitly that the production of iron was unchanging for close to 1500
years. This view was sustained despite the evidence for distinct methods of smelting
that were encountered. Clearly, studies which explore the possibility of historical
change in production need to be undertaken. This thesis addresses the issue of change
by developing a long term perspective on iron production in Zimbabwe.
The hypothesis that change is inherent to iron production was examined through
ethnohistorical/ethnographic, archaeological and archaeometallurgical investigations.
Initially, iron working among the historical Njanja, Karanga and Kalanga was
considered. When compared, some important similarities and differences emerged.
While the principles of the technology were identical, some modifications were
apparent which were peculiar to each group in areas such as the scale of production,
trade and the socio-spatial organisation of technology.
Archaeological studies were conducted at Swart Village, Baranda, Nyanga and
Wedza. The data obtained was supplemented with that archived in the Museum of
Human Sciences in Harare. Again, there were some major outward discrepancies
exhibited in aspects such as furnace types, symbolism and spatial location of
production episodes. The remains from the production process were then studied in
the laboratory using standard archaeometallurgical procedures.
While the production process was similar for early and later sites, constrained by the
underlying principles of the bloomery process, some changes took place over time.
Slag from Swart Village was tapped while that from other sites was not. The 19th
century Njanja improved their furnaces by using many tuyeres and bellows which
increased their efficiency beyond any known archaeological case in Zimbabwe. When
viewed diachronically, the continuities and changes detected in this study demonstrate
that change was an integral part of the technological past. Therefore future studies of
iron production will need to take this issue of change further by constructing local
histories of iron working in areas where no research has been done to broaden our
knowledge of the development of the process over time.
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TABLE OF CONTENTS
List of illustrations
List of tables
Acknowledgements
Chapter 1: Introduction..........................................................................................................10
Introduction..............................................................................................................................10
Eurocentric perspectives on pre-colonial African Iron working.........................................11
Afrocentric perspectives on pre-colonial African Iron working..........................................19
Research Aims: An Outline..................................................................................................21
Perspectives on prehistoric iron production: the chaine operatoiretheoretical approach
22
Avenues for exploring an archaeometallurgical past.........................................................27
Summary..............................................................................................................................29
Chapter Two: Issues in African Iron Production..............................................................31
Introduction.............................................................................................................................31
The technological variables of indigenous iron smelting...................................................33
Ores.................................................................................................................................33
Charcoal..........................................................................................................................36
Clay..................................................................................................................................37
Furnaces..........................................................................................................................38
Air....................................................................................................................................40
The chemistry of the process.............................................................................................41
Iron Smithing......................................................................................................................44
History of investigations.....................................................................................................46
Origins of African Metallurgy..............................................................................................50
The single origin hypothesis...........................................................................................51
Multiple origins hypothesis.............................................................................................55
Ethnoarchaeology - social dimensions...............................................................................57
Technology..........................................................................................................................66
Developing new approaches...............................................................................................70
Conclusion...........................................................................................................................71
Chapter Three: Zimbabwe's metallurgical past................................................................75
Introduction.............................................................................................................................75
Early encounters with metal working in Zimbabwe...........................................................82
Ethnographic Observations.................................................................................................83
Archaeological evidence......................................................................................................89
Attempts to marry technological and symbolic aspects...................................................104
Conclusion..........................................................................................................................105
Chapter Four: Ethnographic Accounts: Njanja, Karanga and Kalanga iron
production in the late 19th and early 20th centuries......................................................107
Introduction............................................................................................................................107
Background information....................................................................................................109
The Ethnographic Approach: oral traditions, direct historical testimonies and
ethnohistory.......................................................................................................................113
The rocks that make iron: mining the ore........................................................................117
Charcoal Preparation..........................................................................................................120
Day selection, building furnaces, tuyeres and bellows....................................................121
Iron smelting in the late 19th and early 20th centuries.....................................................126
Iron smithing......................................................................................................................128
Rituals and taboos..............................................................................................................130
Distribution of the finished product..................................................................................132
Smelter and the smith in society.......................................................................................134
Summary.............................................................................................................................136
Chapter Five: The Archaeological Record: Swart Village and Baranda, northern
Zimbabwe.................................................................................................................................140
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Introduction...........................................................................................................................140
Data collection: Intra-site studies.....................................................................................142
Swart Village......................................................................................................................143
Excavations....................................................................................................................146
The Finds: Iron working remains.................................................................................152
Other finds.....................................................................................................................155
The typological description and analysis of pottery from Swart Village.....................156
Swart Village within the wider context.........................................................................160
Baranda..............................................................................................................................163
Excavations....................................................................................................................165
The Finds: Iron working remains.................................................................................170
Other Finds....................................................................................................................172
The typological description and analysis of pottery from Baranda.............................173
Baranda within the wider context................................................................................176
Summary............................................................................................................................178
Chapter Six: The historical period: Nyanga and Wedza in perspective....................180
Data collection: localised surveys, Nyanga.......................................................................180
Upland Nyanga...................................................................................................................184
Lowland Nyanga................................................................................................................187
Summary.............................................................................................................................193
Wedza................................................................................................................................192
Iron Mines on the Wedza Mountains................................................................................198
Summary............................................................................................................................203
Chapter Seven: Archaeometallurgical Investigations...................................................205
Introduction...........................................................................................................................205
Remains of iron working tell a story: archaeometallurgical theory.................................206
Archaeometallurgical approaches and techniques...........................................................207
Context, Sampling Procedures and Macroscopic observations.......................................210
Reflected Light Microscopy: Mineralogical and microsctructural analyses of iron working
remains..............................................................................................................................220
Chemical Analyses.............................................................................................................223
Results: Swart Village.......................................................................................................224
Baranda..............................................................................................................................232
Wedza................................................................................................................................238
Nyanga...............................................................................................................................244
Summary............................................................................................................................259
Chapter Eight: Discussion and interpretation.................................................................263
Introduction...........................................................................................................................263
Interpretation of the evidence: Swart Village..................................................................264
Interpretation of the evidence: Baranda..........................................................................270
Interpretation of the evidence: Wedza............................................................................274
Interpretation of the evidence: Nyanga...........................................................................277
A comparative perspective on iron working in the Iron Age...........................................281
Conclusion.........................................................................................................................296
Chapter Nine: Conclusions: a broader view of iron production in pre-colonial
Zimbabwe and beyond..........................................................................................................300
Introduction: a story of continuity and change....................................................................300
Iron technology in the Iron Age: a view through time....................................................301
Continuity or discontinuity: the role of technology in society and the spatiality of iron
production in the Iron Age................................................................................................307
Directions for future research...........................................................................................317
References...............................................................................................................................320
Appendices...............................................................................................................................332
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List of Illustrations
Figure 1 Map of Africa showing the location of Zimbabwe.........................................................11
Figure 2 Diagrammatic representation of a typical Shona non-slag tapping iron smelting
furnace. Note that the diagram summarises ail the reactions up to the removal of the
slag and the bloom through the rake channel...................................................................43
Figure 3 Map of Zimbabwe showing EIA sites mentioned in the text.......................................78
Figure 4 Map of Zimbabwe showing Late Iron Age sites mentioned in the text.......................81
Figure 5 shows that most items of Shona material culture were decorated with human
features including drums and granaries which were used in public domains (after Bent
1892)....................................................................................................................................85
Figure 6 Soper's Types of Furnaces from Nyanga (a) oval with mouth at end, belt, breasts
and navel, Upper Pungwe (b) oval with mouth at side and projecting arms, Nyahokwe
(c) conical, Tsvitu. Illustrations adapted from Soper (2002, p. 116).............................100
Figure 7 shows that fertility symbolism was expressed on pots, furnaces and items of dress
(after Collett 1993)............................................................................................................102
Figure 8 Map of the Zimbabwe Plateau showing the location of the groups of people studied
108
Figure 9 Map of Zimbabwe showing the research areas...........................................................109
Figure 10 Schematic representations of ethnographic iron smelting furnaces........................123
Figure 11 Objects made by Shona smiths (photographs taken with due permission from the
Museum of Human Sciences)............................................................................................133
Figure 12 Map of Zimbabwe showing the research area and selected sites............................142
Figure 13 Map of Swart Village showing the first excavations................................................148
Figure 14 Map of Swart Village showing the second excavation.............................................148
Figure 15 section drawing of Trech 1, view from the south.....................................................149
Figure 16 section drawing of Trench 2, view from the east....................................................150
Figure 17 section drawing of Trench 3, view from the south..................................................151
Figure 18 section drawing of Trench 4, Swart Village..............................................................152
Figure 19 Iron working remains from Swart Village..................................................................154
Figure 20 Vessel Forms, Swart Village.......................................................................................158
Figure 21 Decorated pottery from Swart Village.......................................................................159
Figure 22 Decorated pottery from Madzinga Farm (after Pikirayi 1993)..................................161
Figure 23 Decorated pottery from Kadzi, after Pwiti (1996).....................................................161
Figure 24 Map of Baranda showing the excavated areas..........................................................167
Figure 25 section drawing of Trench 1, Baranda, view from the west.....................................168
Figure 26 shows stratigraphy of Trench 2, Baranda, view from the west...............................169
Figure 27 shows section drawing of Trench 3, Baranda, view from the east..........................170
Figure 29 Iron working remains from Baranda..........................................................................172
Figure 30 Vessel Forms from Baranda.......................................................................................174
Figure 31 Decorated sherds from Baranda................................................................................175
Figure 32 Pottery from Kasekete and Mutota, mid-Zambezi valley (after Chirikure eta/. 2001)
...........................................................................................................................................177
Figure 33 Map showing the research area in Nyanga...............................................................183
Figure 34 Iron smelting furnaces from upland and lowland Nyanga........................................190
Figure 35 a) northern view of quarry used to obtain iron, b) ore lumps on the surface,
eastern side of the quarry.................................................................................................199
Figure 36 View of the iron smelting site from the north..........................................................200
Figure 37 Iron working remains from Gandamasungo, Wedza Mountains..............................202
Figure 38 Vitrified furnace wall from Nyamurondo Homestead................................................213
Figure 39 Tuyere fragments from Swart Village and Baranda..................................................214
Figure 40 Tap/flow slag, Swart Village......................................................................................214
Figure 41 Furnace slag with adhering ceramic from Wedza....................................................215
Figure 42 Smithing hearth bottom from Wedza.......................................................................216
Figure 43 Crown material from Upper Pungwe........................................................................217
Figure 44 Hydrated iron ore from Upper Pungwe....................................................................218
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Figure 45 Photomicrograph of tap slag sample from Swart Village Trench 1, Layer 3 (x50
mag). Note the two slag flows separated by the magnetite skin and the perpendicular
nature of the fayalite........................................................................................................225
Figure 46 Photomicrographs of furnace slag from Swart Village (a) dendritic wuestite
intergrown with skeletal fayalite and (b) dendrites of wuestite in a fayalitic matrix.....226
Figure 47 Ternary diagram from Swart Village.........................................................................231
Figure 48 Individual slag flows separated by a band of magnetite, Baranda, (a). Trench 1,
Layer, 3 and (b). Trench 3, Layer 1. Note the spinifex structure of the fayalite in sample
(b)......................................................................................................................................233
Figure 49 Photomicrographs of crown material from Baranda showing metallic iron (bright
white interspersed with wuestite and fayalite in (a), (Trench 1 Layer 3) and (b) smithing
slag Baranda Trench 1 Layer 3, showing wuestite in a fayalitic matrix..........................234
Figure 50 Photomicrograph: x200 mag Baranda ore, Trench 3, Layer 2................................235
Figure 51 ternary diagram presentation of iron working remains from Baranda...................237
Figure 52 Photomicrographs of Wedza flow slag......................................................................239
Figure 53 Photomicrograph of a nodule of haematite from the iron smelting site.................242
Figure 54 Photomicrograph of ore from the smelting site showing haematite which is
consolidated by iron hydroxide x50. mag.........................................................................242
Figure 55 Ternary diagram presentation of analysed samples from Wedza...........................243
Figure 56 Ternary diagram presentation of slags from Upper Pungwe....................................247
Figure 57 Photomicrograph of smithing slag from Nyamuzihwa Falls showing the abundance
of leucitic inclusions x 100 mag.......................................................................................249
Figure 58 Photomicrograph of smithing slag from Nyamuzihwa Falls showing the abundance
of leucitic inclusions x 500 mag.......................................................................................250
Figure 59 Phase diagram of slag from Nyamuzihwa Falls.........................................................250
Figure 60 Photomicrograph of crown material from Demera showing metallic iron, wustite,
some corrosion x 500 mag................................................................................................252
Figure 61 Ternary diagram presentation of slags from Demera............................................253
Figure 62 Photomicrograph showing the ore and wuestite dissolving into slag. xlOO mag.... 256
Figure 63 Photomicrograph showing haematite and magnetite (these ore particles are in the
middle of a wustite dominated slag) x 500 mag. xp........................................................256
Figure 64 Ternary diagram plot of slag and technical ceramics from Nyamurondo Homestead
...........................................................................................................................................258
Figure 65 photograph showing differences between tuyeres from Swart Village and Baranda
...........................................................................................................................................287
Figure 66 tuyeres fused in pairs, Wedza surface collections....................................................287
Figure 67 shows that fertility symbolism was expressed on items of material culture used in
public domains...................................................................................................................295
List of tables
Table 1 below summarises the key features of early iron working as it was practised by the
groups considered in this discussion.................................................................................136
Table 2 Stratigraphy of Trench 1, Swart Vilage.......................................................................149
Table 3 Stratigraphy of Trench 2, Swart Village........................................................................149
Table 4 shows stratigraphy of Trench 3, Swart Village.............................................................151
Table 5 shows stratigraphy of Trench 4, Swart Village.............................................................151
Table 6 shows stratigraphy of Trench 1, Baranda.....................................................................168
Table 7 shows stratigraphy of Trench 2, Baranda.....................................................................169
Table 8 shows stratigraphy of Trench 3, Baranda.....................................................................170
Table 10 Summary of field observations in lowland and upland Nyanga...............................193
Table 11 The weight and frequencies of the categories of remains from Swart Village,
Baranda and Wedza...........................................................................................................219
Table 12 The weight and frequency of the categories of iron working remains from Nyanga.
220
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Table 13 shows average XRF results per materials from Swart Village. See Appendix for all the
results.................................................................................................................................224
Table 14 shows average XRF results per materials from Baranda. See Appendix for all the
results.................................................................................................................................232
Table 15 shows average XRF results per materials from Wedza. See Appendix for all the
results.................................................................................................................................238
Table 16 shows average XRF results per materials from Upland Nyanga. See Appendix for all
the results..........................................................................................................................244
Table 17 shows average XRF results per materials from Lowland Nyanga. See Appendix for all
the results..........................................................................................................................254
Table 18 Key characteristics of iron working at Swart Village, Baranda, Nyanga and Wedza 283
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Acknowledgements
I am very grateful to several individuals and institutions that have generously supported me
during the course of study. I would like to single out Professor Peter Ucko, the Director of the
Institute of Archaeology for his assistance with funding applications and sharing with me the
stress when some unexpected circumstances threatened to derail my study. In addition, Peter
has been more of a father to me and I should share the success of this work with him. Still at
the Institute, Professor Thilo Rehren and Dr Andrew Reid also assisted in making funding
applications. Let me also extend my gratitude to Mrs Barbara Brown who together with Peter,
Thilo and Andrew attended to the frequent requests that I had. In Zimbabwe, Professor
Gilbert Pwiti was always ready to assist with whatever request I made. His assistance with
fieldwork funds for the eastern Zimbabwe research shows his selfless nature. I would like to
thank the coordinators of the Archaeology of Manyikaland Project, Professors Randi Haaland
and Gilbert Pwiti for incorporating me in their project in Zimbabwe.
Financial assistance from the Wenner Gren Foundation came at a very timely moment when I
was contemplating saying adios to archaeology. Over the years, I have developed a special
relationship with the Foundation. The International Programmes Administrator Professor
Pamela Smith helped to strengthen this relationship and the invitation to attend a special
grantees conference at the Foundation in 2004 gave me an opportunity to present to the
Foundation the fruits of their support and shows the confidence which the organisation has in
me.
Without my supervisors Dr Andrew Reid and Professor Thilo Rehren, this work would not
have achieved its present character. I can’t remember the number of times that I have knocked
on Andy’s door for informal as well as formal meetings. Thanks very much Andy for making
sure that I stay focussed in order to finish this work in time even if at times the odds were
against me. Thilo Rehren was always ready to assist with the finer details of
archaeometallurgy. Having introduced me to the subject Thilo’s comments were thought
provoking and I remember one time hitting my head because I could not comprehend what is
now a very simple principle. Drs Bill Sillar and John Merkel also assisted with ideas.
Professor Gilbert Pwiti developed a great interest in my research, commenting on whatever I
asked him to read. His criticism has helped me to develop critical thinking on many issues
regarding the rise of complex societies in northern Zimbabwe. I do not remember the number
of times that I held telephone conversations with Gilbert and in those conversations he
assured me that indeed I had a future and a contribution to make to the discipline of
archaeology. Many thanks for being my mentor and a source of inspiration. May the Lord
bless you!
Apart from generously giving me their unpublished data for northern and eastern Zimbabwe,
Drs Robert Soper and Innocent Pikirayi were constant sources of encouragement. Robert
Soper accompanied me to the field to Nyanga to broaden my interpretation of iron working in
the area. In addition, I would like to thank you Robert for reading my draft chapters and
giving me confidence to complete this work sooner rather than later. Mr Manyanga selflessly
processed my samples for l4C dating despite his busy schedule and to him I say thank you
very much brother. I should also thank Mr Paul Mupira for making all my fieldworks in
Nyanga and Wedza possible when Gilbert was away. Dr Webber Ndoro always reminded me
that it was possible to complete this work in three years and his ideas on symbolism
associated with iron working are greatly appreciated. Dr Godfrey Mahachi, the Executive
Director of the National Museums and Monuments of Zimbabwe awarded permits to excavate
in northern Zimbabwe and helped with export permits to study the material at UCL. His
members of staff were also ready to help me particularly when I was doing archival research
in the Museum of Human Sciences. Ms Juliet Maradze and Mr Blessed Magadzike gave me
8
unlimited access to their important documents and databases and to them I say thanks for this
gesture of goodwill.
During the course of my study, 1 developed a strong working relationship with Professors
Duncan Miller and Simon Hall at the University of Cape Town and David Killick at Arizona.
Duncan, Simon and Dave selflessly gave me access to their unpublished manuscripts and
ideas which broadened my comprehension of iron working in southern Africa.
I would not have done justice if I omit Drs Justine Bayley, David Dungworth and Sarah
Paynter from the English Heritage Centre for Archaeology. David and Sarah had the most
unenviable of all tasks, initially introducing me to the laboratory equipment and taking me
through sample preparation, analyses and writing up of the results. To them I say here are the
results of your efforts!
I also benefited from discussions with Godhi Bvocho, Lorraine Swan and Seke
Katsamudanga. This work would not have been possible if I had not received the support that
I got from Mukundi Chifamba and Jo Chikumbirike the technicians in the History
Department. Mukundi and Jo accompanied me to the field, assisted with material analyses as
well as helping me with making some illustrations. Mike Charlton, Simon Groom and Xander
Veldhuijzen were always available to assist whenever I was stuck in the laboratory. Mr Stuart
Laidlaw greatly assisted with photography and his insistence on detail meant that I had to
learn editing photographs. Thanks so much Stuart!
Words cannot express the gratitude which I have towards Abba and the members of my
family. Without them, things would have been worse. Ladies and gentlemen, the support you
have given me is highly appreciated. Abba thank you very much for coping with my long
absence from home and this work is dedicated to you.
The Wenner-Gren Foundation, the Ronald Tylecote Fellowship of the Institute of
Archaeology Awards, and the Institute for Archaeo-Metallurgical Studies (IAMS) have
generously provided funds for my tuition, fees and maintenance while The Archaeology of
Manyikaland Project/NUFU, UCL Graduate School, and the Society of Antiquaries of
London have kindly awarded grants for fieldwork.
Let me once again thank all those who have supported me in my academic endeavours and
those whom I may not have mentioned with names. I thank the Almighty God for giving the
strength and character to remain focussed and composed through thick and thin. While these
individuals and institutions have assisted, errors that remain are my sole responsibility.
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