The geoarchaeological study focuses on the lithological characterization and provenance determination of the rocks of the El Pozuelo dolmens. The difficulty of identifying volcanic rocks in the intensely altered and deformed environment of the Iberian Pyrite Belt has required the implementation of a research methodology combining the archaeological and geological analysis of the megaliths and the area surrounding the Los Llanetes group. A total of 29 thin sections and 14 geochemical analyses (ICP-AES, ICP-MS and REE) have been carried out on samples from the dolmens and potential source areas, focusing on the chemical elements considered immobile during alteration processes. The petrological analyses confirm the identification of different andesite lithotypes and enable us to correlate the rocks used in the construction of the megaliths with source areas and quarries located within a 50–350 m radius. Several patterns are observed in the selection of the rocks, based on the material, visual and symbolic properties of the different lithologies. Foliated andesite is the most common stone used in the monuments, due to its excellent physical properties and technological suitability for extraction and transformation into megalithic supports. Other types of andesite (sheared, massive and amphibole-phyric), white quartz, ferruginous agglomerate and gabbro were also used for different architectural purposes. The results confirm the importance of locally available suitable rocks in determining site location, raw material procurement and monument construction during the Late Neolithic.

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Este trabajo tiene por objeto presentar el sitio megalítico de La Torre-La Janera, ubicado en el Bajo Guadiana (Huelva). Su investigación ha integrado varias técnicas de muestreo, análisis y documentación: prospecciones, geoarqueología, tecnologías de información geográfica y fotogrametría. Los resultados más destacados han sido: a) la constatación de una gran cantidad y variedad de megalitos (menhires, dólmenes, túmulos, cistas y recintos) de diferentes periodos crono-culturales construidos en grauvaca, parte de ellos novedosos en la zona; b) la presencia de monumentos que integran afloramientos como elementos arquitectónicos y simbólicos; c) la probable sincronía entre los menhires y las estructuras funerarias. Su investigación contribuye al avance del conocimiento del megalitismo en la península ibérica, abriendo futuras líneas de estudio, nuevas problemáticas y otras vías de interpretación sobre la génesis y complejidad de la monumentalidad prehistórica.

The study of a set of marine arthropod shells from an archaeological excavation carried out in 1991-1992 in the tholos of La Pastora (Cooper Age Mega-site of Valencina-Castilleja, S Spain), has highlighted the environmental implications and ornamental use as beads not cited so far for this purpose. It is the barnacle species Chthamalus montagui Southward, 1976, of which are preserved 71 complete specimens. In this study a taxonomic analysis of these organisms is carried out, determining their classification and their physical and ecological characteristics, which make them especially suitable for this use. The interpretation is made regarding the environment in which these organisms were collected during the 3rd millennium BCE. Thus, it points towards a protected coastal area, but with a predominant marine influence, such as the wide marine bay that formed the mouth of the Guadalquivir River in those times. Finally, a 2 radiocarbon analysis of one of these beads and two specimens of another species of barnacle collected in the rocks of the monument, provide a time range of 2760-2200 yr BCE. This range is consistent with the period of activity in the monument estimated by other authors.