A team of Spanish archaeologists has unraveled one of the most intriguing mysteries in Iberian prehistory: how a massive stone basin ended up inside the Matarrubilla dolmen near Seville—and why it is at least 1,000 years older than the structure meant to enshrine it.
Their findings, published in the Journal of Archaeological Science, not only confirm the earliest known example of megalithic maritime transport in the Iberian Peninsula but also suggest that the Copper Age society in southern Spain was more complex and interconnected than previously believed.
A Monumental Enigma Inside a Dolmen
The Matarrubilla dolmen, part of the vast prehistoric site of Valencina de la Concepción in Andalusia, has long puzzled researchers due to an unusual artifact discovered inside: a rectangular stone basin measuring 1.7 m long, 1.2 m wide, and nearly 0.5 m high. Weighing more than 2,000 kg, the basin’s sheer size, unique material, and placement within the dolmen’s chamber raised numerous questions.
First documented in 1917, the basin seemed far too large to have been maneuvered through the dolmen’s narrow corridor. Additionally, its distinctive rock—gypsiferous cataclasite with red, green, and white veining—does not naturally occur anywhere near Valencina.
Provenance and Transport: From Distant Quarry to Ritual Center
By using geological and geoarchaeological techniques, the research team traced the stone’s likely origin to the opposite side of the ancient Gulf of Guadalquivir, near present-day Las Cabezas de San Juan, approximately 55 km from Valencina. At the time (around 3000–4500 BCE), the gulf stretched much farther inland than it does today.
Because of the stone’s weight and the distance, the team concluded that prehistoric people transported it via water—on rafts or boats—across the ancient bay. Once ashore, the basin was dragged approximately 3 km uphill, likely using wooden sleds and human or animal power.
This marks the first confirmed instance of riverine or maritime transport of a megalith in Iberian prehistory. Comparable methods have only previously been documented at sites like Stonehenge (UK) and Newgrange (Ireland).
Hellbound and Down 