Extending the Chronology for Blombos Cave, South Africa: Further Evidence for the Origins of Modern Human Behaviour
Total Page:16
File Type:pdf, Size:1020Kb
University of Wollongong Research Online Faculty of Science, Medicine & Health - Honours Theses University of Wollongong Thesis Collections 2010 Extending the chronology for Blombos Cave, South Africa: Further evidence for the origins of modern human behaviour Elspeth H. Hayes University of Wollongong Follow this and additional works at: https://ro.uow.edu.au/thsci University of Wollongong Copyright Warning You may print or download ONE copy of this document for the purpose of your own research or study. The University does not authorise you to copy, communicate or otherwise make available electronically to any other person any copyright material contained on this site. You are reminded of the following: This work is copyright. Apart from any use permitted under the Copyright Act 1968, no part of this work may be reproduced by any process, nor may any other exclusive right be exercised, without the permission of the author. Copyright owners are entitled to take legal action against persons who infringe their copyright. A reproduction of material that is protected by copyright may be a copyright infringement. A court may impose penalties and award damages in relation to offences and infringements relating to copyright material. Higher penalties may apply, and higher damages may be awarded, for offences and infringements involving the conversion of material into digital or electronic form. Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong. Recommended Citation Hayes, Elspeth H., Extending the chronology for Blombos Cave, South Africa: Further evidence for the origins of modern human behaviour, Bachelor of Science (Honours), School of Earth & Environmental Sciences, University of Wollongong, 2010. https://ro.uow.edu.au/thsci/94 Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] Extending the chronology for Blombos Cave, South Africa: Further evidence for the origins of modern human behaviour Abstract Behavioural modernity, however defined, is considered to be the key distinctive feature separating Homo sapiens from earlier hominid lineages. While the fossil and genetic records imply that modern human morphology evolved in Africa between 250 and 150 thousand years (ka) ago, there is currently no unification egarr ding the timing or geographical origins of modern human behaviour (MHB). An increasing body of evidence suggests modern behaviour was present during the African Middle Stone Age (MSA). Defining the origins of MHB equirr es accurate and precise chronologies of when they first emerged. Blombos Cave in South Africa has yielded a collection of well-preserved cultural material from within the MSA layers. These include bone tools, shell beads, engraved ochre slabs and an assemblage of stone artefacts which are believed to represent a dynamic tool industry, the Still Bay (SB). More recently, ochre containers which may contain evidence for the ingredients used to produce paint, have been found in the lower layers of the cave, along with a tool kit, such as bone spatulas, that suggest an even earlier origin of MHB. The likely symbolic significance of these artefacts implies cognitive sophistication of MSA hominids and modern human behaviour previously only asserted in LSA people. Examination of both sediments and anthropogenic deposits within the MSA levels have allowed the MSA layers of Blombos Cave to be subdivided into separate phases and layers. Each of these has been systematically dated in this study using optically stimulated luminescence (OSL) dating techniques. The improved temporal resolution of this site contributes to the debates regarding the key mechanisms behind the emergence of MHB. Two leading theories regarding the emergence of MHB include: 1) environmental change, and 2) demographic change. OSL ages of sediments associated with these MSA levels suggest the SB industry occurred between 70 and 80 ka ago, with the other symbolic behaviours being recognised at ~110 ka. Such ages imply that MHB was present in southern Africa during the MSA and that it occurred sporadically, possibly as an outcome of increased human population and environmental conditions that were happening concurrently. Degree Type Thesis Degree Name Bachelor of Science (Honours) Department School of Earth & Environmental Sciences Advisor(s) Zenobia Jacobs Keywords optically stimulated luminesce, OSL, Still Bay, Howieson's Poort This thesis is available at Research Online: https://ro.uow.edu.au/thsci/94 i FACULTY OF SCIENCE EXTENDING THE CHRONOLOGY FOR BLOMBOS CAVE, SOUTH AFRICA: FURTHER EVIDENCE FOR THE ORIGINS OF MODERN HUMAN BEHAVIOUR ELSPETH HANNAH HAYES “THIS THESIS IS PRESENTED AS PART OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF BACHELOR OF SCIENCE (HONS) OF THE UNIVERSITY OF WOLLONGONG.” OCTOBER 2010 ii The information in this thesis is entirely the result of investigations conducted by the author, unless otherwise acknowledged, and has not been submitted in part, or otherwise, for any other degree or qualification. ____________________________________ Elspeth. H. Hayes 13th October 2010 iii ABSTRACT Behavioural modernity, however defined, is considered to be the key distinctive feature separating Homo sapiens from earlier hominid lineages. While the fossil and genetic records imply that modern human morphology evolved in Africa between 250 and 150 thousand years (ka) ago, there is currently no unification regarding the timing or geographical origins of modern human behaviour (MHB). An increasing body of evidence suggests modern behaviour was present during the African Middle Stone Age (MSA). Defining the origins of MHB requires accurate and precise chronologies of when they first emerged. Blombos Cave in South Africa has yielded a collection of well-preserved cultural material from within the MSA layers. These include bone tools, shell beads, engraved ochre slabs and an assemblage of stone artefacts which are believed to represent a dynamic tool industry, the Still Bay (SB). More recently, ochre containers which may contain evidence for the ingredients used to produce paint, have been found in the lower layers of the cave, along with a tool kit, such as bone spatulas, that suggest an even earlier origin of MHB. The likely symbolic significance of these artefacts implies cognitive sophistication of MSA hominids and modern human behaviour previously only asserted in LSA people. Examination of both sediments and anthropogenic deposits within the MSA levels have allowed the MSA layers of Blombos Cave to be subdivided into separate phases and layers. Each of these has been systematically dated in this study using optically stimulated luminescence (OSL) dating techniques. The improved temporal resolution of this site contributes to the debates regarding the key mechanisms behind the emergence of MHB. Two leading theories regarding the emergence of MHB include: 1) environmental change, and 2) demographic change. OSL ages of sediments associated with these MSA levels suggest the SB industry occurred between 70 and 80 ka ago, with the other symbolic behaviours being recognised at ~110 ka. Such ages imply that MHB was present in southern Africa during the MSA and that it occurred sporadically, possibly as an outcome of increased human population and environmental conditions that were happening concurrently. iv ACKNOWLEDGEMENTS Completion of this thesis would not have been possible without the help and support of several individuals. I would firstly like to thank my supervisors, Dr Zenobia Jacobs and Professor Bert Roberts, for all your help and support over the past year. Thank you for allowing me to explore a highly significant (and fascinating!) area of research and for giving me the amazing opportunity to travel overseas. I must give additional thanks to Zenobia, for all the hours and effort you put that allowed me to finalise this thesis. Your patience and enthusiasm was invaluable. Thank you to my friends and colleagues working beside me in the OSL lab, not only for fielding my many impromptu questions but also for making this past year an enjoyable experience. To Terry Lachlan and Gitte Jensen, who introduced me to the OSL lab in the early days, your insights were most helpful. I would also like to thank Jose Abrantes, Paul Carr and Nathan Jankowski, for all the help with sample preparation and XRF analyses, and particularly Nathan, whose efforts in regards to this project have been greatly appreciated. Thank you to Stephanie Kermode, for always offering your help and support, and for encouraging me throughout the year. Finally I would like to say a big thank you to Professor Chris Henshilwood and the team at Blombos, for allowing me to stay at this beautiful location and teaching me about the significance of Blombos. Thank you to my supervisors and Brain Jones, who accompanied me on this research trip. It was a fantastic experience and I am grateful to have been involved. v TABLE OF CONTENTS Chapter 1: Background and study design 1.1 Introduction ...............................................................................................................2 1.2 Study site: Blombos Cave, South Africa ....................................................................4 1.2.1 Description and site location ...................................................................5 1.2.2 Site stratigraphy, sediments