Scuola Dottorale di Ateneo Graduate School Dottorato di ricerca in Scienze Chimiche Ciclo XXIX Anno di discussione 2016 Archaeometric Studies of Historical Ceramic Materials SETTORE SCIENTIFICO DISCIPLINARE DI AFFERENZA: CHIM/12 Tesi di Dottorato di Giulia Ricci, matricola 956083 Coordinatore del Dottorato Supervisore del Dottorando Prof. Maurizio Selva Prof. Elisabetta Zendri Table of Contents Contents Page AIM OF THE THESIS 1 1. The Archaeometric Research 2 Summa ry 2 1.1. Definitions and History 2 1.2. Review on Archaeometric Research Applied on Pottery 5 1.3. Diagnostic Tools in Archaeometric Studies on Potteries 9 1.4. Bibliography 17 2. Ceramic Materials 21 Summary 21 2.1. Pottery in Archaeology 21 2.2. Raw Materials 24 2.2.1. Clay minerals 24 2.2.2. Non-clay materials 26 2.3. Production Technologies 29 2.3.1. Forming, shaping and drying 30 2.3.2. Decoration 31 2.3.2.1. Glazes and enamels 31 2.3.3. Kilns and Firing procedures 35 2.4. Chemical and Physical Reactions during Ceramic Firing Processes 38 2.5. Bibliography 42 3. Materials and Methods 45 Summary 45 3.1. Investigation Strategy 45 I Table of Contents 3.2. Investigation Techniques 48 3.2.1. Fourier-Transform-Infra Red Spectroscopy (FT-IR) 48 3.2.2. Micro-Raman Spectroscopy (μ-Raman) 48 3.2.3. Laser Induced Spectroscopy (LIF) 49 3.2.4. UV-Vis Spectrophotometry 50 3.2.5. X-ray Fluorescence analyses (XRF) 51 3.2.6. Laser Induced Breakdown Spectroscopy (LIBS) 51 3.2.7. X-ray Diffractometry (XRD) 52 3.2.8. Optical Microscopy (OM) 53 3.2.9. Petrographic analysis and Image acquisition 53 3.2.10. Scanning Electron Microscopy coupled with Energy Dispersive X- 53 ray Probe (SEM-EDX) 3.2.11. Mercury Intrusion Porosimetry (MIP) 54 3.2.12. Micro Computed X-ray Tomography (µ-CT) 54 3.3. The Ceramic Samples 56 3.3.1. Raw ceramic specimens made in laboratory 56 3.3.2. Ceramic from the Venetian Lagoon 57 3.3.2.1. Archaeological Excavation in Torcello 59 3.3.2.2. Archaeological sherds 60 3.3.3. German potteries 64 3.3.3.1. Central-Eastern German ceramic production sites 65 3.3.3.2. Central-Eastern German sherds 68 1.1. Bibliography 74 4. Results and Discussion 78 Summary 78 4.1. Analyses and Characterization of Raw ceramic specimens made in Laboratory 78 4.1.1. Raw Material Characterization 78 4.1.2. Chemical, Mineralogical and Microstructural Changes of the Raw 83 Ceramic samples after Firing II Table of Contents 4.1.3. Brief Conclusions on the Chemical, Mineralogical and 102 Microstructural Changes of the Raw Ceramic samples after Firing 4.2. Characterization of Ceramics from Torcello 103 4.2.1. Chemical and Mineralogical Characterization. Results and Discussion 103 4.2.2. Petrographic and Mineralogical Results and Discussion 113 4.2.3. SEM-EDX Analyses. Results and Discussion 115 4.2.4. Microstructural and Porosimetry Results and Discussion 122 4.2.5. Brief Conclusions on the Arcaheometric study on Archaeological Potteries from the Venetian Lagoon 127 4.3. Characterization of German Ceramic Sherds 128 4.3.1. FT-IR Analyses. Results and Discussion 128 4.3.2. μ-Raman Analyses. Results and Discussion 137 4.3.3. LIF Analyses. Results and Discussion 142 4.3.4. UV-Vis Spectrophotometry Analyses. Results and Discussion 145 4.3.5. XRF and LIBS Analyses. Results and Discussion 148 4.3.6. Petrographic and Morphological Results and Discussion 158 4.3.7. Porosimetry Analyses (MIP). Results and Discussion 176 4.3.8. Brie Conclusions on Archaeometric study on German ceramic sherds 180 4.4. Bibliography 182 5. Conclusions & Future Perspectives 190 5.1. Bibliography 196 6. GLOSSARY 199 7. ABSTRACT 201 Acknowledgements 203 III AIM OF THE THESIS AIM OF THE THESIS Ceramics are complex objects, rich source of information and constitute a large part of the staple memory of past and present human activities. Therefore, the study of this material is essential in order to thoroughly understand the materiality of historical events and their echo in the present. Archaeometric research on potteries are focused on studying their production techniques, provenance, age, usage and conservation state. The archaeological interests regard many issues as the cultural identity of the potters, the functional aspects of the ceramics, the organisation and technology of the pottery workshops, the availability of the raw materials, the reconstruction of the far-reaching trade relationships, etc. In order to contribute in these issues, scientific material analyses, able to provide the characterisation of the chemical and morphological features of the artefacts which are connected to production aspects, are forcefully involved in this research field. In line with the strongly archaeological interest, the aim of this research was to evaluate the incidence of the production techniques on the final features of the ceramic artefact, considering all the phases of the ceramic life cycle including selection and use of raw materials, manufacturing processes and firing conditions. The present research was carried out by means of traditional and innovative techniques exploring their applicability in this research field encouraging the use of non-destructive techniques. The proposed innovative techniques have been only recently used in cultural heritage material investigation and their application in archaeometric research on potteries was assessed in this research work. Furthermore, this research would highlight the relevance of complementary information obtainable by a multi-analytical approach in order to deeply understand the complexity of the ceramic objects and provide insights on production technology which has an essential role in ceramic manufacturing. 1 1. The Archaeometric Research 1. The Archaeometric Research Summary This chapter would underline how the study and awareness of cultural heritage, such as its material composition, the production technology as well as its conservation state, are fundamental for its preservation and why enable in understanding of historical events, ancient culture and usage. The art object becomes a storyteller, which is able to describe environmental, anthropological and cultural contexts. The chapter starts defining archaeometry and the archaeometric research, and their history is breafly discussed. Afterwards, it provides an overview on archaeometric research and tools used in archaeometric studies of pottery. It has to be notice that archaeological and art-historical methods provide primary information of the material heritage and scientific analyses are nowadays strongly requested. Furthermore, it is shown that cooperation between different specialists is therefore extremely important. 1.1. Definitions and History Archaeometry is an interdisciplinary research area where complementary approaches cooperate to investigate cultural heritage materials. It can be considered a bridge between humanities, such as archaeology and art history, and natural sciences, as chemistry, physics, biology and geology. Archaeometric research includes a wide range of studies and can be defined as the application of scientific techniques for the knowledge and characterization of artefacts and their involvement with humans and environment [1]. The age, use, production technique, provenance and environmental data are some of the achievable information as result of this investigation. Moreover, also conservation science partially overlaps with archaeometry, because the study of the conservation state provides insights on how to preserve and restore the material. The application of natural science methods, in particular chemistry, to characterize cultural heritage objects has its origins since 18th century when the German scientist Martin Heinrich Klaproth in 1796 determined the chemical composition of some Greek and Roman metal coins. Later, other chemists were involved in scientific studies of ancient objects, and in 1842 the German chemist Dr. F.R. Göbel published all his results obtained by chemical analyses of archaeological findings. He was the first to assert that the chemical analyses should be an aid 2 1. The Archaeometric Research to archaeology, by starting the cooperation between scientists and archaeologists. In fact, for the first time in 1853 chemical analysis was inserted as appendix within an archaeological report, made by the British archaeologist Austen Henry Layard [2], [3]. In the same period, Dr. Ernst Freiherr von Bibra1, German naturalist, chemically analysed metal objects and published in 1869 the work entitled “Die Bronzen und Kupierlegierungen der alten und altesten Volher mit Rucksichtuahme auf jene der Neazeit” (“The Bronze and Copper Alloys of the Old and Most Ancient Peoples”) regarding more than 1000 quantitative analysis on metals as result of 82 researchers’ work [4]. Not only metals were investigated from a chemical point of view, but also ceramic materials, even earlier than mineralogical investigations. In 1829, Alphonse Buisson, personal assistant to Alexandre Brongniart, director of the Sevres factory, analysed Italian potteries measuring out silicon, aluminium, iron, calcium, magnesium and water. His work in publishing was continued by Louis-Alphonse Salvétat, chief chemist at the National Laboratory of Porcelain Manufacture in Sevres [5]–[7]. Physical methods were applied in 1896 once Wilhelm Conrad Röntgen, German engineer and physicist, discovered and applied X-rays on paintings to study pigments, such as lead pigments. Fundamental discoveries were made by Nobel Prizes in the same period: Antoine Henri Becquerel, French physicist, along with Marie Skłodowska-Curie