Ancient civilization built bridge in Mallorca at least 5600 years ago
The recent discovery of an ancient submerged bridge in the Genovesa Cave, located on the island of Mallorca, opens a new window into the history of human colonization of the Balearic Islands. This stone bridge, dated to approximately 5,600 years ago, suggests that humans might have inhabited the Western Mediterranean region much earlier than previously believed.
The Genovesa Cave, located along the coast of Mallorca, features a series of submerged passages due to the rising sea levels over millennia. The discovery of the stone bridge, which is 7.7 meters (25 feet) long, was made by a team led by Professor Bogdan Onac of the University of South Florida. Professor Onac and his team used advanced dating techniques and mineralogical analysis to determine the age of the structure, revealing that the bridge was constructed around 5,600 years ago.
According to Onac, "the presence of this submerged bridge and other artifacts indicates a sophisticated level of human activity, implying that the early settlers recognized the water resources of the cave and strategically built infrastructure to navigate it." This discovery sheds new light on the abilities of the early inhabitants of the Balearic Islands, suggesting that they had not only the knowledge but also the technological capability to construct complex infrastructures.
Reconstructing the Early Human Colonization of the Balearic Islands
Reconstructing the history of human colonization of the Balearic Islands is a challenge for archaeologists, primarily due to the limited archaeological evidence available. The earliest evidence of human presence in the archipelago dates back to about 9,000 years ago, but these were often fragmentary and unreliable due to the poor preservation of materials datable by radiocarbon, such as bones and pottery. More recent studies had suggested a timeline for human settlement of around 4,400 years ago, based on finds of charcoal, ash, and bones found on the island.
However, the discovery of the submerged bridge in the Genovesa Cave, in Mallorca, provides a new line of evidence that could change this timeline. The calcite formations and the color band on the bridge serve as proxies for tracking historical changes in sea level and for precisely dating the construction of the bridge.
Climate Changes and Migration Chronology
A particularly interesting aspect of Onac's team's research involves the analysis of climate changes and sea level during the Holocene, a period that spans from about 11,700 years ago to the present. The authors of the study discovered that the construction of the bridge was likely influenced by a rapid rise in sea level just before 6,000 years ago, followed by a period of stability that lasted several hundred years.
During this period of stability, between 5,964 and 5,359 years ago, the so-called Phreatic Overgrowths on Speleothems (POS) formed in the cave lake, and a characteristic "bathtub ring" developed on the bridge. This ring is a precise indicator of sea level during its formation and provides tangible evidence of the chronology of human presence in the cave.
"The construction of the bridge probably began early during this period when crossing the 0.25-meter-deep lake required its construction. However, the structure must have been completed before 5,600 years ago, when the top of the bridge was submerged," explained Professor Onac.
Precise Dating
The dating of the bridge was made possible through the analysis of mineral overgrowths on the bridge and the elevation of a color band. These methods allowed researchers to determine that the bridge was constructed nearly 6,000 years ago, much earlier than previous estimates, which placed human presence in the archipelago around 4,400 years ago. This new timeline significantly narrows the temporal gap between settlements in the Eastern and Western Mediterranean, suggesting earlier human migration and colonization than previously thought.
Evidence of Advanced Prehistoric Engineering
The evidence indicates that humans constructed a stone-paved path leading to the cave's water pool and a sturdy bridge, facilitating access to the only other dry section of the cave located beyond the lake, in the Sala d'Entrada. The construction of such structures in such a remote and submerged environment requires considerable engineering knowledge and complex social organization.
However, the exact reasons behind the construction of these structures in the Genovesa Cave, in Mallorca, remain elusive. While it is clear that the ancient inhabitants of the island had the necessary skills to build complex infrastructures, the reason why they chose to build a bridge in a submerged cave is still under study. It may have had a ritual or spiritual significance or it may have been built for practical reasons, such as accessing water resources.
The discovery of the submerged bridge in the Genovesa Cave, in Mallorca, is one of the most significant in recent years regarding the understanding of the prehistory of the Balearic Islands and the Western Mediterranean. It not only suggests a much earlier human presence in the area than previously thought but also highlights the advanced engineering capabilities of the island's ancient inhabitants.
