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A group of 533 nummi from to the Tomares hoard, found in Seville in 2016, has been studied to characterize their metallic composition. The coins selected were struck in the mint of Carthage between AD 297 and 307. The statistical analysis of the non-destructive XRF data increase our understanding of a mint which has been paid less attention that others to date, in both material and historical terms. No differences in the composition of the coins were detected; i.e. the same alloy was used in all four of the mint’s officinae. However, coins minted at the beginning of the first tetrarchy were found to present higher concentrations of silver.

Pocas veces tenemos la oportunidad de sumergirnos en un tesoro monetario de un tamaño lo suficientemente grande como para conocer en profundidad aspectos clave de la circulación monetaria de un territorio en un determinado momento. Con respecto a la Bética occidental y el periodo de la Tetrarquía, la ocasión surgió en abril de 2016 cuando la maquinaria que realizaba unas obras en el parque público de El Zaudín (Tomares, Sevilla) sacó a la luz de forma accidental el llamado «Tesoro de Tomares». Tras un periodo de dificultades en el que al cierre del Museo Arqueológico por obras se ha unido la pandemia (y post-pandemia), a fines de verano pasado pudo retomarse el pleno trabajo en el conjunto. Estamos ya, por tanto, en situación de realizar una aproximación al Tesoro a partir de los primeros resultados numismáticos y metalográficos. Rarely do we have the opportunity to dive into a coin hoard of a sufficiently large size to gain in-depth knowledge of key aspects of the monetary circulation of a territory at a given time. With respect to western Baetica and the period of the Tetrarchy, the opportunity arose in April 2016 when machinery carrying out works in the public park of El Zaudín (Tomares, Seville) accidentally brought to light the so-called ‘Tomares Hoard’. After a difficult period in which the closure of the Archaeological Museum due to works was combined with the pandemic (and post-pandemic), full work on the site was restarted at the end of last summer. We are now, therefore, in condition to make an approximation to the treasure on the basis of the first numismatic and metallographic results.

Hoy en día, el estudio de objetos antiguos de metal incluye el análisis por medio de métodos físico-químicos no destructivos desarrollados en las décadas pasadas. Uno de los parámetros más importantes que deben conocerse de una muestra es su composición química, ya que esta información contribuye significativamente a la determinación de varias suposiciones y a la respuesta de muchas preguntas que surgen mientras se estudia un objeto de gran valor histórico. La fluorescencia de rayos X es una técnica bien conocida y muy empleada en el análisis elemental de objetos antiguos de metal y el nuevo desarrollo del microhaz focalizado de rayos X descrito en este texto incrementa su adecuación para el estudio de técnicas antiguas de fabricación y decoración. Esta técnica de análisis superficial se complementa con la técnica de transmisión de rayos gamma, que ha sido utilizada para la estimación de la composición en el interior de monedas de plata-cobre y objetos realizados en otras aleaciones del cobre. Describimos también el sistema de microfluorescencia confocal portátil desarrollado por nuestro Grupo para la obtención de perfiles en profundidad de forma no destructiva. The study of ancient metal artefacts includes nowadays the non-destructive analysis by means of chemical-physical methods developed in the past decades. One of the most important parameters to be known from a sample is its chemical composition, as this information significantly contributes to the determination of several assumptions and to the response of many questions arisen from the study of a valuable heritage object. X-ray fluorescence is a well-known technique very much employed for the elemental analysis of ancient metal artefacts and the new implementation of a microfocused X-ray beam described in this text increases its applicability for the study of manufacture and decorative ancient techniques. This surface analytical method is complemented with the Gamma Ray Transmission technique, which has been employed in the bulk composition estimation of silver-copper coins and other copper based alloy samples. We also describe a portable confocal microfluorescence system developed by our Group to obtain non-destructive depth profiles. Ministerio de Economía y Competitividad (España) HAR2012-33002 Ministerio de Economía y Competitividad (España) HAR2015-67113-P Junta de Andalucía P09-HUM4544

Archaeological silver–copper alloys are usually affected by silver enrichment of the near surface layers, either intentional or fortuitous. In previous studies we have shown that surface composition of archaeological bronzes and leaded copper coins obtained by XRF can be corrected by means of gamma-ray transmission (GRT) to obtain the bulk composition. In the present work, we have studied the applicability of this method to silver–copper alloys and established the most suitable conditions for the GRT correction calculation. The analysis of the microstructure of the core and the corrosion layers of a set of silver roman coins shows that copper could be leached from the surface during corrosion and cleaning treatments, resulting in an apparent silver surface enrichment. After the correction calculations by GRT method, the concentrations of the major elements, Ag and Cu, were found to be in good agreement with the bulk composition obtained by direct analysis of the cut cross-sections of the coins. The GRT method shows to be a useful tool to study metal artefacts having a surface composition modified by corrosion or cleaning treatments.

Archeological pieces with high Ag concentrations often have a surface enrichment of Ag. Usually, researchers in this field do not agree on the causes of these enrichments, one of which could be the cleaning procedures. In this work, a set of 18 ancient Greek silver coins was selected to study the effects of different cleaning procedures in terms of producing a surface Ag enrichment. The aim of this study is to find and select the less aggressive one in terms of the lower modification of Ag concentrations and visual aspect. These coins were analyzed by X-ray fluorescence (XRF) before and after each cleaning procedure.

Falta resumen y palabras clave.

Trabajo presentado al I Congreso Internacional “El Patrimonio Cultural y Natural como motor de desarrollo: Investigación e Innovación” celebrado en Jaén del 26 al 28 de enero del 2011., Trabajo parcialmente financiado por los proyectos HAR2009-07449 del Ministerio de Ciencia e Innovación y P09-HUM-4544 de la Junta de Andalucía.

Ministerio de Ciencia e Innovación (España) HAR2009-07449 Junta de Andalucía P09-HUM4544