Seafaring megaliths: robust evidence for Neolithic monolith transport

Seafaring megaliths: A geoarchaeological approach to the Matarrubilla giant stone basin at Valencina (Spain)

 Luis M. Cáceres Puro, Teodosio Donaire Romero, José Antonio Lozano Rodríguez, Marta Díaz-Guardamino, Francisco Martínez-Sevilla, Alicia Medialdea, Miren del Val, Jonàs Alcaina-Mateos, Joaquín Rodríguez-Vidal, Fernando Muñiz Guinea, Juan Manuel Vargas Jiménez, Miguel Ángel Rogerio-Candelera, Leonardo García Sanjuán,

Journal of Archaeological Science, Volume 180, 2025, 106263,

ISSN 0305-4403,

https://doi.org/10.1016/j.jas.2025.106263.

(https://www.sciencedirect.com/science/article/pii/S0305440325001128)

Abstract: A broad multidisciplinary approach is deployed to study an exceptional megalithic feature: the stone basin that presides over the chamber of the Matarrubilla tholos, part of the Valencina Copper Age mega-site (Sevilla, Spain). The study, including geoarchaeological characterisation and sourcing of the stone, traceological analysis of its surfaces based on photogrammetry and morphometrics, digital image analysis as well as OSL dating, leads to a number of substantial findings of great relevance to understand the significance of this stone basin, the only of its kind documented to this date in the Iberian Peninsula, with parallels only in Ireland and Malta. Among the most relevant conclusions, it is worth noting the fact that the gypsiferous cataclasite block the basin was made of was brought from the other side of the marine bay that five thousand years ago extended across the south-east of Valencina, this is the first evidence of waterborne transport of a megalithic stone in the Iberian Peninsula. In addition, the basin appears to have been put where it stands today sometime in the first half of the 4th millennium BC, long before any tholoi were built at Valencina, which suggest a prior history of still poorly documented monumentality at this mega-site.

Keywords: Valencina cooper age mega-site; Matarrubilla tholos; Stone basin; Megalithic art; Gypsum rock; Transportation of megaliths; Floating transport

 
Key Scientific Methods Used

Geoarchaeological Characterisation and Provenance Analysis

•  The study conducted a full geological analysis to determine the stone's origin. By comparing the mineralogical and petrographic properties of the basin with regional geological formations, researchers established that the gypsiferous cataclasite block originated from the opposite (eastern) side of a prehistoric marine bay, across from the Valencina site.
•  This sourcing was crucial in demonstrating that the stone could not have been obtained locally and must have been transported over water.

Traceological Analysis Using Photogrammetry and Morphometrics

•  High-resolution photogrammetry and morphometric analysis were employed to model the basin’s surfaces, documenting tool marks and manufacturing techniques. This allowed for detailed assessment of the basin's carving and dressing, providing insights into Neolithic stone-working skills and the logistics of moving such a large object.

Digital Image Analysis

•  Digital imaging was used to enhance the identification of tool marks and surface modifications, supporting interpretations of both manufacture and transport processes.

Optically Stimulated Luminescence (OSL) Dating

•  OSL dating of sediments beneath the basin provided a chronological framework, establishing that the basin was placed in its current location in the first half of the 4th millennium BC—predating the construction of the tholos itself. This temporal evidence supports the hypothesis of an earlier phase of monumentality at the site.

Interpretation and Broader Context

The multidisciplinary approach not only traced the stone’s geological origin but also reconstructed the likely transport route: the basin was moved across a marine bay (now vanished) and then hauled uphill to its final position. This scenario is supported by:

•  The lack of similar gypsum outcrops near the site, necessitating cross-water transport.
•  Comparative references to similar waterborne megalith transport in other prehistoric contexts, such as Stonehenge’s bluestones and the kerbstones of Newgrange, where geological sourcing and hypothesised river/coastal routes have been similarly established.

Conclusion

 This study exemplifies how integrating geological, archaeological, and advanced imaging methods can provide robust evidence for Neolithic monolith transport mechanisms. The combination of provenance analysis, morphometric documentation, and precise dating offers a model for future research into prehistoric monument construction and the capabilities of early societies in moving massive stones over challenging landscapes.