Physico-chemical characterisation of a one hundred thousand year old ochre processing toolkit from Blombos Cave, South Africa A Masters Dissertation submitted to the faculty of Science, University of the Witwatersrand in fulfillment of the requirements for the Masters` degree DIKELEDI S. MPHUTHI Johannesburg 2016 DECLARATION I declare that this research is my own, unaided work. It is being submitted for the Degree of Master of Science at the University of the Witwatersrand, Johannesburg. It has not been submitted before for any degree or examination at any other University. …………………………………… (Signature of Candidate) …22nd ……..Day of......July 2016...................... Supervisors: Prof Ewa Cukrowska (WITS University, School of Chemistry) Prof Christopher Henshilwood (WITS University, Evolutionary Studies Institute; University of Bergen, Institute for Archaeology, History, Culture and Religion) Co-supervisor: Luke Chimuka (WITS University, School of Chemistry) i ABSTRACT The Middle Stone Age (MSA) levels (c. 100 – 72 ka) (thousand years) at Blombos Cave, South Africa, contain buried remnants of human existence and their activities (these include ochre-stained shell beads, processed ochre pieces, bone tools, stone tools, and ochre processing toolkits). A preliminary study on the occupation layers at Blombos Cave was done in order to chemically and physically characterise the sediment deposits. The interpretation of the information preserved in these sediments, as a result of human activities, was achieved by using the following characterisation techniques: FT-IR, ICP- OES/MS, CHNS analysis as well as pH and EC measurements. Fluctuations in the bio-essential trace elements (K, P, Mg, Ca, S, Fe, Al, Cr, Na, Cu and C) and in the markers of in situ burning (P, K, C, Ca and Mg) through the MSA levels suggested a non-contiunous anthropogenic occupation of the cave. Further, the dark coloured layers were indicative of periods when heavy human activities, such as fire use, were encoutered. These layers were characterised by high levels of P, K, C, Ca and Mg, also elevated pH and EC levels were observed. The calcite origin for these sediment deposits was confirmed to be pyrogenic. The layers found to contain large bone, ochre and shell densities (with no evidence of fire use) had high levels of Fe, P high Ca and low EC. The calcite origin for these sediment deposits was geogenic. Biogenic calcite was only observed in the more recent CA and CC layers. Substantial amounts of ochre assemblages were recovered from the MSA levels at Blombos Cave. Among these was an ochre processing toolkit recovered from the CP layer (c.100 ka). Ochre is abundant in African archaeological sites after 165 ka and is likely to have played a symbolic role in the lives of prehistoric people. It contains an iron-oxide mineral as well as accessory minerals. When mixed with a binder (such as fat or water) ochre can be used as a pigment. A large number of fragmented bone remains were found in the M1 and M2 levels. It is suggested that the majority of the fragmentation occurred while the bones were in a fresh state; implying marrow extraction by the site occupants. The exploitation of bone ii marrow was crucial in order to extract the fat and use it as a binder during the pigment production. Some of the broken and marrow-extracted bones were heated and used as fuel during seasons when wood was scarce while the other bones were deliberately engraved for symbolic intent. The characterisation of the ochre processing toolkit was achieved by mineralogical analysis and elemental fingerprinting. FT-IR analysis revealed that the general matrix of the ochre samples comprised of hematite (Fe2O3) or goethite (α-FeO(OH)) as the main chromophores and clay minerals (such as kaolinite (Al2Si2O5(OH)4), muscovite [(KF)2(Al2O3)3(SiO2)6(H2O)] and illite [K(Al4Si2O9(OH)3)]), calcite (CaCO3) and quartz (SiO2) as the main accessory minerals. PXRD analysis confirmed Fe2O3, Al2Si2O5 (OH)4, [K(Al4Si2O9(OH)3)] and SiO2 to be the predominant mineral phases in the ochre, implying this specific type of ochre was preferred during the production of the pigment. Fe2O3 contributed the red hue and the aluminosilicates their clayey properties making them good extenders of the pigment. Multivariate statistics and Fe ratios made it possible to identify elements important for differentiating the ochre recovered from the CP layer. Analysis of variance (ANOVA one-way) showed a statistically significant difference between the ochre residues in terms of trace elemental profiling. The variance suggested different geological origins for the ochre. FT-IR was used as a screening technique for any organic residues associated with the toolkit and GC-MS was used to identify the preserved organic residues. These were mostly lipids and terpenes. The identified bio-molecular markers; stearic acid and dehydroabietic acid were exploited to give insight on the origin of the residues. Stearic acid suggested the use of animal fat while dehydroabietic acid implied the use of a resin (potentially as a binder in the pigment). The characterisation investigations revealed that the prehistoric populations at Blombos Cave specifically sourced hematite and aluminosilicate- containing ochre pigments in order to fulfil their social and cultural demands. The MSA site iii occupants’ chemical understanding of these materials suggested they were technologically advanced. Keywords: Blombos Cave, MSA levels, ochre, mineralogical analysis and elemental fingerprinting. iv DEDICATION To my loving parents, Mr and Mrs Mphuthi, thank you for always believing in me. v ACKNOWLEDGEMENTS I would like to express my sincere gratitude to Prof Ewa Cukrowska, Prof Christopher Henshilwood, and Prof Luke Chimuka for having given me the opportunity to work under their supervision. Their complete support and guidance has led to the successful completion of my research as well as their constructive criticism and comments on the various drafts of the dissertation. I would like to thank Dr Karen van Niekerk for providing me with the samples that made it possible to carry out this interesting research. I would also like to express my sincere appreciation to the late Dr Stanley Moyo for his mentorship and advice throughout my research and for his assistance with the use of most instruments especially ED- XRF and FT-IR. I would like to thank all the members of the Environmental Analytical Chemistry Research group who helped me cope with all the challenges I have come across through my studies, they made my work in the lab pleasurable through their limitless help and support. In particular, I would like to thank Lehlononolo Serithi for his constant support, encouragement and patience. I would also like to thank my friend, Ontibile Molefe, who kept me going even when times were tough. Some analysis would have not been possible if it was not for Prof D. Billing would allowing us access to use PXRD instrument in his lab and Mr Hlengi Nyoni at University of Johannesburg for GC-MS analysis. My studies would have not been possible if it was not for the National Research Foundation (NRF) for providing the entire funding for my studies and living expenses. To the one who made it all possible, my Lord and King, Christ Jesus, who is the author and perfector of my faith. Without whom none of this would have been possible. Thank you. vi CONTENTS PAGE DECLARATION ................................................................................................................. i ABSTRACT ........................................................................................................................ ii DEDICATION .................................................................................................................... v ACKNOWLEDGEMENTS ............................................................................................... vi CONTENTS PAGE .......................................................................................................... vii LIST OF FIGURES ........................................................................................................... xi LIST OF TABLES ........................................................................................................... xvi ABBREVIATIONS AND ACRONYMS ...................................................................... xviii CHAPTER ONE ................................................................................................................. 1 Introduction ......................................................................................................................... 1 1.1 Background on the southern African Middle Stone Age .......................................... 2 1.2 Blombos Cave stratigraphy and ages of the deposits ................................................ 4 1.2.1 The ochre processing workshop in the M3 phase .............................................. 7 1.3 Description of the research problem investigated ..................................................... 7 1.4 Motivations ............................................................................................................... 8 CHAPTER TWO ................................................................................................................ 9 Literature review ................................................................................................................. 9 2.1 Blombos Cave and its link to complex cognition in the Middle Stone Age ........... 10 2.1.1 Bifacially