SAUDI ARABIA WAS A GREEN OASIS MILLIONS OF YEARS AGO STUDY OF 'DUHOOL AL-SUMMAN' REVEALS

RIYADH, April 10 (Bernama-SPA) -- The Saudi Heritage Commission on Wednesday announced that a scientific study analysing 22 cave formations, locally known as "Duhool Al-Summan," concluded that the Kingdom of Saudi Arabia was a green oasis eight million years ago.

Saudi Press Agency (SPA) reported that the Director General of the Commission's Antiquities Sector Dr Ajab Alotaibi, said that the study revealed one of the world's longest climate records based on cave deposits.

This record covers a period of eight million years, representing the longest climate record in the Arabian Peninsula.

Alotaibi further stated that the study highlights the Arabian Peninsula's crucial role as a corridor for the dispersal of organisms between Africa, Asia and Europe. This finding contributes to a greater understanding of the history of biodiversity and the intercontinental movement of species through the region.

He also noted the study's relevance to interpreting the impact of climate change on the movement and dispersal of human populations throughout history.

The Heritage Commission has published this groundbreaking scientific study in the prestigious journal Nature under the title “Recurrent Humid Phases in Arabia Over the Past 8 Million Years.”

Conducted in collaboration with leading local and international institutions, the study is part of the commission’s flagship initiative, the Green Arabia Project, which aims to explore the region’s natural and environmental history.

The research brought together 30 scientists from 28 organisations-both local and international-including the Heritage Commission, the Saudi Geological Survey, King Saud University, the Max Planck Institute in Germany, Griffith University in Australia, and several universities and research centres across Germany, Italy, the UK, and the United States.

This study provides the most detailed climate record ever documented for the Arabian Peninsula, using data collected from 22 cave formations (stalagmites and stalactites) in seven sinkholes north-east of Riyadh, near Shawyah in Rumah Governorate. These caves, locally known as Duhool Al-Summan ("sinkholes"), preserved rich geological layers that tell a compelling story of the region’s environmental past.

The findings reveal a succession of humid periods that turned what is now arid desert into a lush, life-sustaining landscape. Contrary to its present-day dryness, Saudi Arabia once supported fertile ecosystems, acting as a natural bridge for the migration of animals and early humans between Africa, Asia, and Europe.

To date these climatic shifts, researchers conducted advanced geochemical analyses of the cave deposits, including oxygen and carbon isotope testing, which allowed them to trace fluctuations in rainfall and vegetation over millions of years.

They also used Uranium-Thorium (U-Th) and Uranium-Lead (U-Pb) dating techniques to precisely determine the age of the deposits and identify distinct humid phases-some dating as far back as the late Miocene, around eight million years ago, continuing through the Pliocene and into the late Pleistocene.

The study confirms that these humid phases played a vital role in enabling the movement and dispersal of mammals and other species across continents.

It also supports earlier fossil evidence pointing to the presence of now-extinct, water-dependent animals, such as crocodiles, hippos, elephants, giraffes, cattle, horses, and large African predators, which once thrived in Arabia’s ancient rivers and lakes, long lost to the desert climate of today.

According to the Heritage Commission, this study marks a major milestone for the Green Arabia Project, one of Saudi Arabia’s most ambitious efforts to promote scientific research and document the natural and cultural heritage of the Arabian Peninsula.

The project seeks to better understand how environmental and climatic changes have shaped the region across eras-contributing to a richer, more complete understanding of Saudi Arabia’s natural history.

The commission reaffirmed its commitment to advancing research and fostering international collaboration in this field. It also emphasised the importance of preserving the Kingdom’s natural and cultural heritage and revealed that more studies are under way.

Despite the significance of these discoveries, Saudi Arabia’s cave systems remain largely unexplore—holding immense potential for future scientific breakthroughs and deeper insights into the region’s ancient past.

-- BERNAMA-SPA