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An interdisciplinary approach comprising archaeological, chemical, mineralogical, and luminescence data was applied to a better understanding of the fill dynamic and chronologies of a calcite-rich negative archaeological feature from Southern Portugal. This work aims to contribute to the assessment of the human involvement in the backfilling actions of a negative archaeological feature from a Chalcolithic site, thus better defining the moments of its destruction and/or abandonment. There are well-known limitations of luminescence dating of calcite-rich materials, particularly in the dose rate determination. In this work, a proposal of two innovative protocols to determine the dose rate of calcite-rich contexts is discussed. A clear improvement of the dose rate estimation was obtained by using the "radionuclide weighed" protocol. The comprehensive used methodologies enabled to define the infill phases and the sources of the infill materials. The luminescence profiling studies were also useful to describe the infill processes, highlighting their discontinuity and pointing to different deposition rates. The luminescence ages obtained, when using the "radionuclide weighed" protocol proposed in this work, are closer to the archaeological evidence of a Chalcolithic occupation. FCT (Portuguese Science and Technology Foundation)Portuguese Foundation for Science and Technology [UID/Multi/04349/2013, BL 36/2016_IST-ID, UID/GEO/04035/2013, PTDC-CS/ANT/104333/2008] FCTPortuguese Foundation for Science and Technology [SFRH/BD/62396/2009, SFRH/BPD/114986/2016] info:eu-repo/semantics/publishedVersion

The Mousterian stratigraphy of Gruta da Oliveira (Torres Novas, Portugal) contains one of the latest occupations by Neanderthals on the Iberian Peninsula. Thermoluminescence (TL) dates on heated flints were obtained for layers 13 and 14, and compared with the radiocarbon (charcoal and burnt bone) and U/Th (secondary carbonates) dating results available for those layers and the succession as a whole. As the internal dose rates are very low, the TL age estimates are very dependent on the external dose rates, which show significant variation, including indications of spatial patterning. Through close inspection of the radiation geometries of samples and dosemeters, the appropriate gamma dosimetry is identified and the weighted mean TL ages (1-σ) calculated accordingly are 55 ± 7 ka for layer 13 and 77 ± 8 ka for layer 14. These ages are stratigraphically consistent with the radiocarbon chronology for layers 9–11 and with the termini ante and post quem provided by U-series dating for the beginning and end of the accumulation of the deposits. The TL results corroborate that all radiocarbon dates below layer 11 are minimum ages only and, given the constraints derived from the proxy data available, place layer 13 and 14 post MIS 5. Sample as well as dosemeter numbers are low at Gruta da Oliveira, which limits the precision of TL-dating of a prehistoric human activity. Further refinement of the chronostratigraphy will be based on U-series dating of non-human-related, interstratified secondary carbonates.

[EN]Bulk samples of mortars from the Santa Eulalia de Bóveda temple (NW Spain) have been characterized from a chemical and mineralogical point of view, with the aims of contributing technological and provenance inferences, and evaluating possible correlations with the various identified stages along historical periods of construction. Mortar samples were analyzed by X-ray diffraction and neutron activation analysis. Mineralogical associations found are similar (quartz, alkali feldspars, calcite and mica) for all samples, only varying in their proportions, mainly calcite. Statistical and geochemical studies allowed the differentiation of two main groups, enhancing definition of the granite nature of the aggregate, and of a significant variation in calcite proportion (lime binder). Two outlying samples were identified: one with higher calcite proportion and other corresponded to a plaster with a different raw material source. A clear correlation between the chemical groups and the independently defined chronological stages could not be found in this work. However, mortar samples from the earlier stage were associated with a higher aggregate/binder proportion., [ES]La mayoría de las muestras tomadas del conjunto monumental de Santa Eulalia de Bóveda (Noroeste de España) se han caracterizado desde un punto de vista químico y mineralógica, con el objetivo de obtener algunas conclusiones sobre aspectos tecnológicos y de procedencia de los materiales, así como evaluar las correlaciones que pueden existir con las distintas etapas constructivas identificadas mediante otro tipo de estudios. Las muestras de mortero se analizaron por difracción de rayos X y por activación neutrónica. Las asociaciones mineralógicas encontradas (cuarzo, feldespatos alcalinos, calcita y mica) son similares para todas las muestras, sólo variando en sus proporciones, principalmente de calcita. Los estudios estadísticos y geoquímicos permitieron diferenciar dos grupos principales, uno en el que se aprecia una mejora de la definición de la naturaleza del granito del agregado, y otro con una variación significativa en la proporción de calcita (cal aglomerante). Se identificaron dos muestras periféricas: una con una mayor proporción de calcita y otras corresponden a un yeso con una fuente de materia prima diferente. No se ha determinado en este trabajo una correlación clara entre los grupos químicos y las etapas cronológicas definidas de forma independiente. Sin embargo, en las muestras de mortero pertenecientes a las etapas más tempranas se identificó un agregado / aglutinante en mayor proporción que en las muestras pertenecientes a etapas posteriores.

In this paper, the characterization of Roman amphorae from the Porto dos Cacos (PC) and Quinta do Rouxinol (QR) workshops, in the Tagus estuary, dating to a period between the 1st and 5th century AD was carried out on the basis of instrumental neutron activation analysis data on 260 amphorae fragments, together with mineralogical compositional studies obtained by X-ray diffraction. Special attention was devoted to the study of the Dressel 14, Almagro 50/51c and Lusitana 3/9 amphorae in an attempt to establish whether or not it is possible to establish any correlation between the composition and typology, and between and within the production centres studied. A description of the geochemical patterns associated with each production centre was first carried out separately, followed by a discussion comparing the two centres situated in the same sedimentary basin, identifying diagnostic chemical tracers for each one; also, in certain cases, a relative correlation with the typology was achieved. Both the definition of reference groups and the attribution of amphorae to their workshop origin relied on the use of chemometric techniques for data structure analysis, coupled with geochemical data analysis, especially regarding trace element data and its geochemical behaviour and distribution according to the geological environment of the region. This approach complements and reinforces the conclusions drawn from typological and archaeological analyses. Considering the two kiln sites studied, we may talk of the production of two types of Roman amphorae in the lower Tagus, with the establishment of compositional groups defined according to their corresponding chemical signatures. The products of the PC workshop are characterized by high concentrations of Co, As and U, and low concentrations of Fe, Zn, Sb, Rb, K; QR workshop amphorae show instead higher concentrations of Fe, Sb, and also of Rb and Zn, and lower amounts of U. These results make it possible to understand the crucial importance of the lower course of the Tagus River within the framework of the analysis of the economy of the estuary at the time. This, in turn, may lead to a better understanding of production and trade within Lusitania and also with other Roman provinces.