Characterisation and Provenance of Archaeological Lithic Materials by Chemical Methods

Esta tesis doctoral se ha realizado mediante un compendio de cinco trabajos publicados en revistas internacionales indexadas que incluyen los estudios arqueométricos de caracterización química llevados a cabo sobre los materiales arqueológicos de tipo lítico siguientes: las materias primas silíceas de la Comunidad Valenciana y los artefactos en sílex de la Cueva de la Cocina (Dos Aguas, Valencia), los materiales de construcción de la antigua ciudad de Sagunto y de su Castillo (morteros y sillares de roca carbonatada), y las ánforas conservadas en el Museo Arqueológico de Sagunto. En todos los estudios hemos desarrollado y optimizado enfoques basados en la caracterización de los materiales a través de los métodos propios de la química empleando sobre todo técnicas de espectroscopía atómica y molecular. En particular, tienen un papel central el análisis multielemental y los elementos de las tierras raras como marcadores de procedencia. La introducción a los trabajos se desarrolla en tres apartados. En el primero se expone un cuadro general de la ciencia arqueológica, indicando como nuestra investigación se inserta en la disciplina y explicando los principios de las técnicas analíticas y estadísticas empleadas. El segundo ofrece una rápida revisión sobre la utilización de enfoques arqueométricos para estudiar los diferentes materiales analizados en los artículos, además de ilustrar las problemáticas planteadas y las razones detrás del muestreo, así como la elección de determinados protocolos analíticos, con una reflexión sobre la calidad de los datos resultado del análisis multielemental. El tercer capítulo resume los resultados y las conclusiones de los trabajos, y propone posibles direcciones para investigaciones futuras. Finalmente, los cinco artículos están incluidos en los anexos.This doctoral thesis has been realised by the collection of five works published in international indexed journals which include archaeometric studies of chemical characterisation carried out on the following archaeological lithic materials: the siliceous raw materials of the Valencian Community and the chert artefacts of Cueva de la Cocina (Dos Aguas, Valencia), the building materials of the ancient city of Sagunto and of its Castle (mortars and carbonate rock ashlars), and the amphorae conserved in the Archaeological Museum of Sagunto. In each study we have developed and optimised approaches based on the characterisation of the materials by the methods of Chemistry especially using atomic and molecular spectroscopy techniques. In particular, a central role was held by multielement analysis and rare earth elements as provenance markers. The introduction to the works was developed in three sections. In the first one, we have shown the general framework of Archaeological Science, evidencing how our research places itself in the discipline and explaining the fundamentals of the used analytical and statistics techniques. The second chapter shows a short review on the use of archaeometric approaches for the study on the different materials analysed in the papers, displaying the considered issues and the reasons beyond the sampling, as well as the selection of certain analytical protocols, with a reflection on the quality of the data obtained by multielement analysis. The third chapter resumes the results and the conclusions of the works, and proposes possible direction of future reasearches. Finally, the five papers are included in the annexes

The building stones of the apsidal walls of the Pisa’s Cathedral

This paper reports the preliminary data about the stones used in the apsidal walls of the Cathedral of Pisa. The research was made during the study and restoration works of the monument, under the supervision of the Opera della Primaziale Pisana. The collected data shows the prevalence of stones commonly used in the historical buildings of the city. The main lithotypes are the marbles from the Monte Pisano and from the Apuan Alps. Moreover, there are numerous ashlars of Proconnesian marble and two capitals of Pentelic and one of Paros marbles, three lithotypes used during the Roman Age and coming from the Eastern Mediterranean. The wall of the loggia of the third storey is almost entirely made up of a calcarenite (Panchina) coming from the area South of Livorno. Black limestone from the Monti d’Oltre Serchio, and serpentinite and red marly limestone outcropping in different areas of Tuscany, were also identified

Chemical characterisation of cherts from the valley of Serpis river (Alcoy, Alicante) for archaeological purpose

Mobility range and territorial control are central questions for Archaeology in the study of human groups’ life during Prehistoric Ages. A key point to get to grips with this set of problems is to understand the dynamics of supply of natural resources such as food and raw materials. Thus, the identification of the outcrops of chert and their characterisation is essential, due to the use of this particular rock as raw material for the production of several different tools. Since the nakedeye description of stone characters (colour, translucency, presence of carbonatation or patina, etc.) often lacks to identify different outcrops and to determine the provenance of a sample, in the last decades, scientists have tried to develop methods to improve the characterisation of this rock from the chemical, mineralogical and petrographic point of view [1,2]. This contribution shows the study of some chert varieties which were widely used since the Paleolithic by the inhabitants of the valley of Serpis river [3], in the southern part of the Valencian Community. Forty-three samples of Serrat, Mariola and Serreta chert were collected from different kinds of outcrops: from the wall rock, and from fluvial and colluvial deposits. The cortex or crust and the nucleus of each sample were mechanically separated and individually analysed to control the variability caused by the amount of cortex and consequently to develop a methodological approach that permits to identify different chert sources in a restricted area. For this purpose, Xray fluorescence and Inductively coupled plasma mass spectrometry analyses have been carried out to determine major elements, trace elements and rare earth elements [4] of cherts affected by different depositional and post-depositional conditions. [1] Luedtke, An Archaeologist's Guide to Chert and Flint (1992) 172. [2] Skarpelis et al., J. Archaeolog. Sci.: Rep. 12 (2017) 819. [3] Molina Hernández, El sílex del Prebético y cuencas neógenas en Alicante y sur de Valencia :su caracterización y estudio aplicado al Paleolítico Medio, tesis doctoral (2015) 902. [4] Murray, Sediment. Geol. 90 (1994) 213

Rare Earth Elements to identify archaeological strata in the Cocina Cave

Rare earth elements (REE) have been employed in a variety of different scenarios in order to identify the natural or anthropogenic nature of archaeological soils [1,2] . In this study, REE signatures were employed to better understand the layers formation in a cavity called Cocina cave, a large cavity of 300 m2 located at Barranco de la Ventana, one of the ravines flowing southwards from La Canal valley, a little plateau located in the municipality of Dos Aguas (Valencia, Spain). Cocina cave is characterized of very homogenous sediment deposition where it is difficult to understand layers formation processes just employing the traditional archaeological methods and the standardized soil analyses. The archaeological sequence encompasses last hunter-gatherer Holocene occupations in the regional sequence (Mesolithic) followed by several levels attributed to the Neolithic, Bronze Age and historic occupations until the XX century, these last regarding the use of the cavity as a pen. In order to understand the development history of the strata and the anthropogenic or natural formation of soils a total of fifty samples were taken across six different sections (A, B, C, D, E, F, G) and from each section the sampling was carried out at different depths through 1-2m deep sections. All samples were recovered from current pits excavated at the cavity corresponding with some profiles that encompass different strata including natural deposits and hunter and penning activities together with other possible uses not well defined from archaeological data. Several radiocarbon dates confirm the anthropogenic use of the cavity from the IX millennium cal BP to the contemporary times. Major, minor and trace elements including REE were determined employing XRF and ICP- MS. Results were then statistically processed and cross-referenced with archaeological data to aid interpretation. The results show that REE provide interesting details regarding the strata development history, and therefore help archaeologists to better understand the occupation, use and abandonment phases of the cave. [1] Pastor et al., TrAC 78 (2016) 48. [2] Gallello et al., JAS 40 (2013) 799

Chemical characterisation of historic mortars to evaluate decay and construction phases

The chemical characterization of ancient mortars allowed the researchers to answer relevant questions about production technologies, raw materials supply, construction phases and state of decay. In this work one hundred and sixteen samples were collected from different structures during two archaeological excavations carried out in Sagunto’s city centre (Valencia, Spain). The studied area has been interested by several continuous phases of occupation since the Iberian Epoch (5th century BC) to the present times [1,2]. The samples were analysed employing X-ray fluorescence and Inductively coupled plasma mass spectrometry to determine major and trace elements. The obtained data was statistically processed with Sagunto’s Castle mortar results [3], allowing us to identify the construction phases of most of the wall structures, confirming the particular effectiveness of Rare Earth Elements analysis to distinguish mortars from different periods. In conclusion, according to this data, the state of conservation of the different mortars has been evaluated. [1] Ripollés, Opulentissima Saguntum (2004) 165. [2] Monserrat, Arse 41 (2007) 231. [3] Gallello et al., Microchem. J. 132 (2017) 251

Chronological classification of ancient mortars employing spectroscopy and spectrometry techniques : Sagunto (Valencia, Spain) case

Forty-two mortar samples, from two archaeological excavations located in Sagunto (Valencian Community, Spain), were analysed by both portable energy dispersive X-ray fluorescence spectroscopy (pED-XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to determine major and minor elements, and traces including rare earth elements (REE). Collected data were crossed with those previously obtained from Sagunto Castle mortars and principal component analysis (PCA) was applied to discriminate the construction phases of the unearthed buildings. REE permitted to ascribe most of the masonries to the Roman Imperial period. Moreover, a statistical model was built by employing partial least squares discriminant analysis (PLS-DA) in order to classify the mortars from Roman Imperial period and from Islamic period, due to the problematic overlapping between these two phases. Results confirmed the effectiveness of the developed indirect chronology method, based on REE data, to discriminate among historic mortars from different construction periods on a wide scale including different Sagunto archaeological sites

The source of the building stones from the Sagunto Castle archaeological area and its surroundings

A multidisciplinary study was carried out on the building stones of the masonries belonging to the Castle of Sagunto (Valencia, Spain), an important historical and archeological complex, characterized by several construction phases from the Roman Period to the Modern Ages. For the first time, the stones of the Sagunto Castle have been analysed to determine their chemical, mineralogical and petrographic features, the main physical and mechanical properties, and to understand their decay, use and recycling dynamics in the different building during the entire occupational period. Geochemical and mineralogical analyses employing X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray diffraction (XRD) were carried out together with optical and electronic microscope analysis to observe the stone macro- and micro-structures. The collected data were processed by Principal Component Analysis (PCA) to highlight differences among the studied structures. The results show that the stones employed to build Sagunto`s structures during the different historical periods are related to a specific quarried area located nearby Sagunto Castle hill and differences between the studied samples are mostly related to the conservation state of the buildings. Therefore, geochemical analyses confirm the origin of the raw materials, while petrographic and physical analyses have been useful to evaluate the conservation state of the studied Sagunto Castle structures

Analysis of stratigraphical sequences at Cocina Cave (Spain) using rare earth elements geochemistry

This study investigates the stratigraphical sequence of Cocina Cave (Spain) employing and testing for the first time the capability of rare earth elements as markers of human activities in caves. Located in Dos Aguas (Valencian Community, Spain), Cocina Cave is characterized by the presence of several Holocene archaeological deposits from the final Mesolithic to the present day and is a pivotal site for understanding the socio‐ecological dynamics of the last hunter‐gatherer inhabitants of the Iberian Peninsula and the transition to pastoral and agricultural economies in the Western Mediterranean. However, the identification of strata from particular time‐periods in the cave is often difficult due to the homogeneity of layers, the poor archaeological record in some strata and the presence of severe disturbance phenomena. The methodological approach of this study consisted of cross‐referencing rare earth elements and other chemical markers with the archaeological stratigraphical interpretation, in an attempt to not only support the identification of the anthropic contribution to the formation of Cocina Cave strata, but also to characterize and confirm different natural and occupational episodes, particularly those associated with hunter‐gatherer, early agriculturalist, and shepherd activities. Sediments were collected from different excavation areas and analysed for major elements, trace elements, rare earth elements (REE), soil organic matter (SOM) amounts and pH. Multivariate statistics were employed to group samples according to their elemental profile, and these were then compared to the archaeological temporal interpretation. The obtained results showed that REE amount and fractionation geochemical processes were regulated by carbonates, phosphates and pH. The use of REE as markers was particularly useful as their concentrations and their calculated ratios and anomaly distributions were demonstrated to be highly consistent with the archaeological stratigraphical interpretation

Gli intonaci dipinti e le malte d'allettamento della Villa dei Vetti (Capraia e Limite, Firenze)

L'elaborato verte sullo studio di parte dei frammenti d'intonaco dipinto rinvenuti nel sito archeologico tardoantico della villa dei Vetti, l'analisi coinvolge sia gli aspetti relativi alla decorazione sia quelli riguardanti i materiali utilizzati