Laboratório HERCULES

The bronze hoard of «Cabeço de Maria Candal», or «Freixianda», discovered in 1961 during the preparation of land for planting a vineyard, was presented to the scientific community in 1970. Since then, some works refer materials from this deposit, but its global study is only available now, covering various aspects. The finding was composed of ten artifacts, attributable to the Late Bronze Age, but only nine were recovered: five axes; a dagger; a pair of tongs; a chisel and a deformed piece; the tenth element was a second chisel. In the first part the authors review the data about the discovery, its preservation, previous studies and site location. This is followed by a multifaceted study of the artifacts, morpho-typological, functional, archaeometallurgical (using PIXE, optical microscopy and micro-hardness), and also evaluation of its social dimension and value. It was possible to characterize each one of them in high depth, reaching relevant conclusions, and compare them to other known artifacts, particularly, but not exclusively, from the same region and from the Centre of the Portuguese territory. In some cases, as with the pair of tongs, it was necessary to broaden the typological horizons from the Mediterranean to England. The metallurgy is binary, tending to be high in Sn percentages. As to the metallography, it was found that the objects were suitably prepared through thermo-mechanical cycles intense enough to be used in practical activities. Simultaneously, some attention was directed to studying the association of these various functional types and to the contextual uniqueness of the deposit as a whole. The underlying action behind it and, consequently, the community’s conceptualization and expression of its world view, seems to reveal, metaphorically, a valorization of the labor power and of the control over it. This is expressed in the careful selection of the pieces, since they revealed distinct «biographies», with «life experiences» and «working lives» quite variable and sometimes intense. At the end of the study, the situational and spatial dimension of the finding as a territorial marker is explored, both as a «peripheral deposit», and as reflecting a cross-border positioning, connecting it with other known regional evidence broadly coeval, i.e., inter-active in terms of social reproduction.  At a macro scale, the structuring role of the Estremadura region in the context of the production dynamics, circulation and amortization of bronze in the West of the Iberian Peninsula in the early first millennium BC stands out; as well as, at a global scale, the uniqueness of this last North/South, East/West passage corridor.

Keywords: Late Bronze Age – Estremadura – BronzeHoard – PIXE – Optical Microscopy – Place – Landscape – Community.

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Abstract
Raquel Vilaça*
Carlo Bottaini**
Pedro Sobral de Carvalho***
Giovanni Paternoster****
Resumo
* Universidade de
Coimbra. Centro de
Estudos em Arqueologia,
Artes e Ciências
do Património.
rvilaça@fl.uc.pt
** Universidade de
Évora. Laboratório
Hercules.
carlo@euvora.pt
*** Eon, Indústrias
Criativas, lda.
**** Departamento
de Física da Universidade
de Nápoles
“Federico II”.
Estuda-se um punhal do Bronze Final encontrado em 1941, no lugar das Lameiras (Orgens, Viseu),
no decorrer de actividades de extracção de minério de cassiterite (estanho). Com base na informação
bibliográfica publicada por José Coelho (1949) e na deslocação ao terreno, foi possível
identificar e caracterizar de forma mais circunscrita a área do achado. Os dados morfométricos
e tipológicos do punhal foram completados pelos resultados da análise química por XRF-ED. Ao
contrário das informações publicadas, que o identificavam como sendo de cobre, confirmou-se
estarmos na presença de um artefacto de bronze (Cu+Sn) com percentagem bastante reduzida
de elementos secundários. Esta característica está em sintonia com a de outros punhais congéneres,
de tipo Porto de Mós, do Centro de Portugal. O estado físico da peça, com a ponta quebrada,
e o seu contexto de achado são valorizados pelos autores, que desenvolvem algumas reflexões
de índole social na interpretação do punhal como depósito ritual e metáfora do próprio ciclo
mineiro-metalúrgico.
This paper studies a Late Bronze Age dagger found in 1941 in Lameiras (Orgens, Viseu), yielded
during extracting work in the cassiterite (tin ore) mine. Based on the information published by José
Coelho (1949) and a thorough inspection of the site, an accurate study of the finding place has
been carried out. Morphological and typological data have been completed with XRF-ED chemical
analysis. New data from this study rule out the previous assumption of this item as made of
copper. Analysis reveal a bronze artifact from an alloy made of copper and tin (Cu+Sn) with little
secondary materials. This characteristic is shared with other Porto de Mós daggers from center
Portugal. The authors consider here the physical characteristics of the piece, with the broken tip,
and the finding circumstances. They reflect on some social issues in the interpretation of the dagger
as a ritual deposit and metaphor of the mining-metallurgical cycle.

Abstract
In the present study, two metal artefacts from the Late Bronze Age / 1st Iron Age from Southern
Portugal have been analyzed by X-ray fluorescence (XRF) and Scanning Electron Microscopy with X-ray
microanalysis (SEM+EDS).
Despite typological and functional differences, the two objects have been produced in a binary alloy
(Cu+Sn) with a variable presence of Sn and a quite low impurity pattern (<2.0 wt%). The results allow
to frame the two objects within the well-know metallurgical tradition from Late Bronze Age / 1st Iron
Age from Southern Portugal.
According to an inter-and multidisciplinary approach, the paper has been completed with the realization
of 3D models of the two articles (Annex 1). In the case of objects with a quite complex morphology,
digital techniques allow to create interactive and high-definition 3D images, providing the reader a
better perception of objects.
Key-words
South-West; Late Bronze Age / 1st Iron Age; XRF, SEM+EDS; Virtual Archaeology

Energy dispersive X-ray fluorescence (EDXRF) is awell-known technique for non-destructive and in situ analysis
of archaeological artifacts both in terms of the qualitative and quantitative elemental composition because of its
rapidity and non-destructiveness. In this study EDXRF and realistic Monte Carlo simulation using the X-ray
Monte Carlo (XRMC) code package have been combined to characterize a Cu-based bowl fromthe Iron Age burial
from Fareleira 3 (Southern Portugal). The artifact displays a multilayered structure made up of three distinct
layers: a) alloy substrate; b) green oxidized corrosion patina; and c) brownish carbonate soil-derived crust.
To assess the reliability ofMonte Carlo simulation in reproducing the composition of the bulk metal of the objects
without recurring to potentially damaging patina's and crust's removal, portable EDXRF analysis was performed
on cleaned and patina/crust coated areas of the artifact. Patina has been characterized bymicro X-ray Diffractometry
(μXRD) and Back-Scattered Scanning Electron Microscopy + Energy Dispersive Spectroscopy (BSEM +
EDS). Results indicate that the EDXRF/Monte Carlo protocol is well suited when a two-layered model is
considered,whereas in areaswhere the patina+crust surface coating is too thick, X-rays fromthe alloy substrate
are not able to exit the sample.

The aim of this paper is to provide a chemical study and a microscopical characterization of a group of metals from Late Bronze Age (LBA) found at Porto do Concelho (Central Portugal) and consisting of 2 sickles, 2 palstaves, 3 spearheads, 5 swords, 4 daggers, 16 rings, 1 fibulae, 3 bracelets and 4 undefined objects (fig. 1) [1]. For this purpose, a multi-analytical approach was adopted by integrating chemical and micro-structural data: compositional measurements were performed using a portable XRF Analyser, Metorex X-Met 920, equipped with a Si(Li) detector and an Am-241 source. The metallographic study was made with an optical microscope (OM) Leica, model DMLM, equipped with a digital camera DFC480. Finally, analyses by Scanning Electron Microscopy with X-ray microanalysis (SEM-EDS) was performed with an Hitachi S-3700N interfaced with a Quanta EDS microanalysis system with a Bruker A.XS Xflash® Silicon Drift Detector (129 EVE Spectral Resolution at FWHM/MN Ka). Quantitative elemental analyses were processed using the Bruker ESPRIT software. Operating conditions: backscattered electron mode (BSEM), accelerating voltage of 20 kV, working distance of ~10 mm, current emission of 120 µA, detection limit c. 0.1 wt%. From a chemical point of view, the objects can be divided into two types of copper alloy: thirty-five objects are binary bronzes (Cu+Sn) with a low amount of Pb, while five are leaded bronze alloys (>2.0 wt% Pb). Tin ranges between 7.3 and 29.1 wt%, with a tendentially higher amount in the group of rings. Impurities of Fe, Ni, As, Ag and Sb also appear. OM and SEM-EDS was realized on twenty-two artefacts allowing the identification of the microstructure of the metal, the presence of inclusions, casting defects and phases. Under the optical microscope, ten of the objects exhibit the characteristic features of as-cast microstructures (i.e. dendrites). This suggests that after removing the newly manufactured objects from the mould, the ancient metalworker did not apply any thermo-mechanical treatment to the artefacts. Twelve objects show equiaxial microstructures with annealing twins and, in some cases, slip bands. In this case, the objects were finished with annealing and forging operations. From a mechanical point of view, this treatment makes the metal more resistant and suitable to endure stronger impacts (fig. 2). SEM-EDS displays that the occurrence α+δ eutectoid, irregular shaped unalloyed copper grains and Cu-S inclusions are common feature for almost all the items (fig. 3). Quantitative microanalyses made in corroded layers have also displayed a significant Sn enrichment in the patina by a depletion in Cu content (fig. 4) [2]. To conclude, the archaeometallurgical study of the metals from Porto do Concelho provides data that contribute to the knowledge of the LBA metal productions in Portugal and, by extension, in the Iberian Peninsula and the so-called Atlantic Europe. Acknowledgements: