A TALE OF FOUR CAVES A TALE OF FOUR CAVES: ESR DATING OF MOUSTERIAN LAYERS AT IBERIAN ARCHAEOLOGICAL SITES BY VITO VOLTERRA, M. A. A Thesis Submitted to the School of Graduate Studies In Partial Fulfillment of the Requirements For the Degree Doctorate of Philosophy McMaster University © Copyright by Vito Volterra, May, 2000 . DOCTORATE OF PHILOSOPHY (2000) McMaster University (Anthropology) Hamilton, Ontario TITLE: A Tale of Four Caves: ESR Dating of Mousterian Layers at Iberian Archaeological Sites AUTHOR: Vito Volterra, M. A. (McMaster University) SUPERVISOR: Professor H. P. Schwarcz NUMBER OF PAGES: xviii, 250 Abstract This study was undertaken to provide supporting evidence for the late presence of Neanderthals in Iberia at the end of the Middle Paleolithic. This period is almost impossible to date accurately by the conventional radiocarbon method. Accordingly electron spin resonance (ESR) was used to obtain ages for four Spanish sites. They were EI Pendo in the Cantabrian north, Carihuela in Andalusia and Gorham's and Vanguard caves at Gibraltar. The sites were chosen to allow the greatest variety in geographic settings, latitudes and sedimentation. They were either under exca­ vation or had been excavated recently following modem techniques. A multidisciplinary approach to dating the archaeological contexts was being proposed for all the sites except EI Pendo whose deposits had been already dated but only on the basis ofsedimentological and faunal analyses. This was the first research program to apply ESR to such a variety ofsites and compare its results with that ofsuch a variety of other archaeometric dating teclmiques. The variety allowed a further dimension to the research that is the opportunity ofappraising first hand the applicability and advantages ofa new dating technique and determining its accuracy as an archaeological dating method incomparison with other techniques. Test samples for the research were collected at the sites as well as at the Museo de Ciencias Naturales in Madrid and the Gibraltar Museum. The ESR results for EI Pendo provide a terminus post quem of 31 Ka for the presence ofthe Neanderthal at the site. Those for Carihuela permit the Neanderthal skeletal remains found in layers V and VI to be dated between 45 ka and 74 ka and between 67 ka and 86 ka respectively. The data also confinn the late presence ofthe Neanderthals in Andalusia. The results for the Gibraltar final Mousterian layer also confirm the presence ofNeanderthals in southern Spain at 36.9 ±5 to 40.3 ±5 ka. While there are a number ofsecure dates for early Aurignacian deposits in Spain the results of the present research provide the first solid evidence of the late presence of Homo sapiens neanderthalensis in the Iberian Peninsula. Furthermore, from the data collected it can also be concluded that the ESR method is accurate and eminently suitable for dating archaeological contexts. iii Acknowledgements I am very grateful for the guidance, understanding, continued warm support and empathy of the members ofmy committee Dr. Peter Ramsden, Dr. Jack Rink and especially ofDr. Henry Schwarcz and the Chair ofthe Department of Anthropology Dr. Ann Herring. In fact the entire Anthropology Department Faculty and staff Uanis Weir, Rosita Jordan and not to be forgotten Cookie Brymer) have made working with them a most interesting and enriching pleasurable experience. My thanks go also to Prof. E. Rinehardt for consenting to participate in my defense at such short notice. I wish also to acknowledge the assistance and warm empathy ofProfessor David Counts without whose support the project would not even have started. My thanks are also extended to Jean Johnson whose patience, assistance and good advice proved invaluable. It was Jean that processed all the samples through INAA and prepared some of the Gorham's cave samples for irradiation. I am also grateful to Dr. Daniel Richter for his keen interest and cheerful comments and Dr. John Hmvey for the extensive use ofthe Panasonic reader. I would like to thank Dr. Nick Barton, Dr. Andy Currant, Dr. Clive Finlayson, Ramon Montes Barquino, Juan Sanguino Gonzales, Prof. Chris Stringer, Dr. Gerardo Vega Toscano and his wife Belen for their assistance with various aspects ofthe sample collection and for their generous hospitality at site. The free, open discussions and the interchange of ideas with them has proved a refreshing learning experience that has erniched my knowledge ofthe Neanderthal question and ofthe Paleolithic. I am equally indebted to the Museo de Ciencias Naturales ofMadrid and the Gibraltar Museum for permitting me to use teeth from their permanent collections. But foremost thanks go to my wife Gail who put up with my erratic work habits and my repeated travel to Spain as well as with extended hogging ofthe family computers This research was funded with travel grants from the North Atlantic Treaty Organization to Dr.. H. P. Schwarcz, in collaboration with Dr. W. J. Rink, Dr. V. Cabrera Valdes and Dr. F. Bemaldo de Quiros. iv Table ofContents ABSTRACf Page iii ACKNOWLEDGEl\fEN'TS Page iv TABLE OF CONI'EN'TS Page v UST OF TABLES Page xi UST OF FlGURES Page xii CHAPTER 1: INTRODUCTION 1 - Introduction Page 1 CHAPTER 2: THE EVOLUTION QUESTION 2 - The evolution question Page 5 CHAPTER 3: DATING 3 - Dating Page 12 CHAPTER 4: ESR DATING 4 - ESR dating Page 15 4.1 Factors affecting ESR age determinations Page 29 CHAPTER 5: CAVE ENVIRONMENTS 5 - Cave environments Page 32 CHAPTER 6: TEETII 6 - Teeth Page 33 6.1 Uranium uptake models Page 35 6.2 Other considerations Page 38 CHAPTER 7: EFFECTS OF SAMPLE PREPARAnON 7 - Effects of sample preparation Page 40 CHAPTER 8: ESR APPLICATIONS 8 - ESR applications Page 41 v CHAPTER 9: PHYSICAL CONTEXT 9 - Physical context Page 47 9.1 General Page 47 9.2 Geography and geology Page 49 9.2.1 Cantabria Page 53 9.2.3 Penebetica Page 56 9.2.4 Gibraltar Page 60 9.3 Past ecology Page 60 CHAPTER 10: ARCHAEOLOGICAL CONTEXT 10 - Archaeological context Page 66 10.1 Archaeological activities Page 66 10.1.1 The northern sites Page 66 10.1.2 The southern sites Page 72 CHAPTER 11: ARCHAEOLOGICAL STRATA AND EXCAVATED MATERIAL 11 - Archaeological strata and excavated material Page 84 11.1 Archaeological strata Page 84 11.1.1 El Castillo Page 84 11.1.2 ElPendo Page 85 11.1.3 Carihuela Page 87 11.1.4 GorhaIll's cave Page 93 11.1.5 Vanguard cave Page 99 CHAPTER 12: PROCEDURES 12 - Procedures Page 102 12.1 DosiInetry Page 102 12.2 CaFz phosphor Page 103 12.3 Copper capsules for field dosimetry and their preparation Page 104 12.4 Emplacing and retrieving CaFz capsules Page 106 12.5 Panasonic dosiIneters Page 107 vi 12.6 Emplacing Panasonic dosimeters in the field Page 107 12.7 Retrieving dosimeters from the field Page 110 12.8 Reading the CaFz dosimeters Page 110 12.9 Dose rate calculations Page 111 12.10 Sample collection Page 114 12.10.1 Field collection Page 114 12.10.1.1 Tooth and sediment collection Page 114 12.10.1.2 Procedures for Recovery of In-Situ Teeth Page 115 12.10.1.2.1 Recognition ofteeth and location Page 115 12.10.1.2.2 Recovery of teeth Page 116 12.10.1.2.3 General comments Page 118 12.10.1.3 Moisture samples collection Page 119 12.10.2 Musewn sample collection Page 119 12.10.2.1 Sediments Page 120 12.10.2.2 Preservatives and storage environment. Page 120 CHAPTER 13: SAMPLE PREPARATION 13 - Sample preparation Page 122 13.1 Removal apparatus Page 122 13.2 Tooth numbering and identification Page 122 13.3 Tooth preparation Page 124 13.3.1 Choosing and photographing samples Page 127 13.4 Cutting samples Page 128 13.5 Preparation ofenamel, dentine and cementum Page 128 13.6 UGC analysis Page 130 13.7 Irradiation Page 133 13.8 ESR spectrometry Page 133 13.8.1 Sample density vs. intensity signal. Page 138 13.8.2 Effect of particle size Page 140 vii 13.8.3 Effects of crystal orientation Page 141 13.8.4 Effect ofsample position within the spectrometer cavity Page 143 13.8.5 Experimental repeatability Page 144 13.8.6 De Calculations Page 145 13.8.7 Age detennination Page 145 CHAPTER 14: TIIE FIELD WORK 14 - Field work and site visits Page 149 14.1 El Castillo Cave Page 149 14.2 EI Pendo Cave Page 150 14.3 Carihuela Cave Page 150 14.4 Gorham's Cave Page 153 14.5 Vangtlard Cave Page 155 CHAPTER 15: TIlE LABORATORY WORK 15 - Laboratory work Page 158 15.1 Dosimeters Page 158 15.1.1 "Lumpy" and homogeneous sediments Page 159 15.2 Tooth preparation Page 161 15.3 Sediments Page 162 15.4 Determination ofDe's by Universal Growth Curve Page 163 15.6 Irradiation Page 165 15.7 Spectrometer Measurement Page 165 CHAPTER 16: TIlE ESR AGES 16 - ESR dates Page 166 16.1 EI Pendo Page 166 16.2 Carihuela Page 170 16.3 Gorham's Cave Page 173 16.4 Vangtlard Cave Page 176 viii CHAPTER 17: CONUUSIONS 17 - Conclusions Page 178 APPENDICES Appendix A Page 182 Protorol for field gamma spectrometer readings Page 183 Protocol for annealing CaF2 phosphor Page 184 Protocol for making CaF2 dosimeters Page 186 Protocol for preparing Panasonic dosimeters for the field Page 188 Protocol for reading and zeroing Panasonic Dosimeters Page 189 Protocol for preparing TL cupels Page 191 Protocol for establishing laboratory beta dose for CaF2 dosimeters Page 193 Detailed procedure for measuring TL phosphors : Page 194 Protocol for cleaning TL cupels Page 199 Reconciling measured dosimeter doses and doses calculated from sediments Page 200 Collection ofmoisture samples and moisture measurement.