Unearthing the past: Saudi Arabia's ancient lava tube dwellers

Archaeologists have discovered evidence that people lived in lava tubes in the regions now known as Saudi Arabia. These underground tunnels, created by flowing lava, provided shelter to the inhabitants of the Arabian Peninsula for at least 10,000 years.

In Saudi Arabia, archaeologists found dozens of evidence suggesting that people inhabited a lava cave around 10,000 years ago, possibly even earlier. These findings were made within the Umm Jirsan lava tube system, located about 125 kilometres north of Medina.

The findings and details of the research were published in the journal "PLoS ONE" (DOI: 10.1371/journal.pone.0299292).

The investigation was led by researchers from Australia's Griffith University in collaboration with experts from other institutions. They focused on Umm Jirsan, a lava tube approximately 1.5 kilometres long, 12 metres high, and up to 45 metres wide, making it the largest lava tube in Saudi Arabia. Lava channels or tubes form when hot lava flows through them. Similar structures found on the Moon could potentially serve as shelters for astronauts.

Although the Arabian Peninsula has been inhabited for a very long time, only a few remnants of its past inhabitants remain due to the dry and hot conditions that do not allow organic materials to survive for long. Thus, scientists sought areas where traces of ancient human presence could be preserved, looking for locations protected from the sun, wind, and abrupt temperature changes over the last millennia. The lava tube of Umm Jirsan proved to be an ideal site for this purpose.

In their exploration of underground caves and lava tubes, researchers found examples of rock art, human and animal bones, and various artefacts, including pottery, fragments of fabric, processed pieces of wood, and stone tools. The age of these findings suggests that the Umm Jirsan lava tube had been used as a shelter from as early as 10,000 years ago, in the Neolithic period, for at least seven thousand years, likely up until the Bronze Age.

According to research, caves and lava tubes were not continuously inhabited but provided shepherds relief from the harsh desert conditions as they moved between oases to trade their goods. "Our findings in Umm Jirsan offer a glimpse into the life of ancient people of the Arabian Peninsula, showing recurring periods of habitation within the lava tube and highlighting the pastoral activities that once thrived in this region," stated Dr Mathew Stewart, the lead author of the study. "This place likely acted as a significant landmark on pastoral routes, linking oases and enabling cultural exchange and trade," he further explained.

The rock art and fauna depictions in the lava tubes helped scientists piece together the lifestyle of the Arabian Peninsula's ancient inhabitants. Images of cattle, sheep, goats, and dogs confirm prehistoric husbandry practices.

Isotopic analysis of animal remains indicated that the livestock primarily grazed on wild grasses and bushes. Meanwhile, analysis of human remains revealed a diet high in protein, with an increasing reliance on plant-based foods, mainly cereals and fruits, suggesting agriculture's emergence and evolution.

Sites like Umm Jirsan are invaluable to archaeologists, as the artefacts left behind are shielded from wind, the searing sun, and other weathering processes. "These findings highlight the great potential of interdisciplinary research in caves and lava tubes, providing a unique perspective on the ancient history of the Arabian Peninsula," acknowledged Michael Petraglia from Griffith University.

The last time Umm Jirsan was filled with lava remains uncertain. "Over the past 1,500 years in Arabia, there have been about 1,500 volcanic eruptions, with considerably more in ancient times," noted Stewart.