What 8-million-year-old stalagmites reveal about Saudi Arabia’s lost green past

Researchers at Northumbria University discovered there were multiple humid phases in central Arabia over millions of years. (Getty Images)
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Updated 27 April 2025
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What 8-million-year-old stalagmites reveal about Saudi Arabia’s lost green past

  • Researchers discovered there were multiple humid phases in central Arabia that likely fed ancient river systems
  • These wet periods likely transformed arid deserts into green corridors for animal and early human migration out of Africa

LONDON: Two major surprises greeted researchers in the Department of Geography and Environmental Sciences at Northumbria University when they returned to the UK from Saudi Arabia with samples of ancient stalagmites collected in caves northeast of Riyadh.

The plan was to use the samples to identify specific humid phases in central Arabia over the past million years or so which would have temporarily “greened” the more usually arid region, transforming the so-called Saharo-Arabian Desert Barrier into a land bridge across which many mammalian species ­—­ including early humans — would have made the journey out of Africa.




Hubert Vonhof (right), geologist at the Max Planck Institute for Chemistry, and Alexander Budsky, scientist at the State Museum in Kärten, were part of the team that analyzed dripstones from Saudi Arabian caves. (Supplied)

The initial surprise was that the first, commonly employed technique they used to date such samples did not work.

Two different radiometric dating methods are used to date the calcium carbonate laid down in stalagmites — uranium-thorium (U-Th) and uranium-lead (U-Pb) — which both measure the extent to which radioactive isotopes in the material have decayed.

“At first we suspected the stalagmites might be quite a lot younger, so we used the uranium-thorium method,” said Monika Markowska, a senior research fellow in the Geography and Environmental Sciences Department at Northumbria University in Newcastle, England.

“This method is good only for about 600,000 years, and we kept finding we couldn’t date anything.”

Then came the second surprise, revealed in a paper published in the journal Nature this month.

“So, we switched to the uranium-lead method and all of a sudden it revealed just how old these stalagmites were,” she said.

“There was this sudden realization in the lab: ‘Oh my goodness, these are 8 million years old.’ It was quite a moment.”

At a stroke, the story of life in central Arabia had been pushed back more than 7 million years.

Stalagmites, stalactites and “flowstones,” known collectively as speleothems, are created on the floors, roofs and walls of caves by rainwater dripping through from the surface.




A cross-section of one of the stalagmites taken for analysis. (Supplied)

As water passes through the soil or rock above a cave, it collects minerals, including calcium carbonate. In the case of stalagmites, over many millennia, these minerals form conical towers, slowly growing up from the floor of the cave.

The age and rate at which these stalagmites have grown can be accurately measured using various methods of radiometric dating, which calculates a material’s age by measuring the presence of radioactive elements.

Until recently, evidence of environmental conditions in Arabia extended back only 450,000 years. But in 2020, a paper published in the International Journal of Earth, Climate and Life Interactions reported that analysis of stalagmites collected from caves in southern Arabia — Yemen and northern Oman — had pushed the record back 1.1 million years.

In that time, analysis of the stalagmites revealed there had been no fewer than 21 “pluvial periods” — periods of increased rainfall, creating “numerous opportunities” for early humans to migrate out of Africa and into Eurasia, unimpeded by the more typical periods of arid weather and desert conditions that otherwise acted as barriers to early human dispersal.

But, as the authors of the latest research report in Nature said, “although numerous humid phases occurred in southern Arabia during the past 1.1 million years, little is known about Arabia’s paleoclimate before this time.”

The new research has now pushed back the region’s hydroclimate record a further 7 million years, in the process revealing much earlier “recurrent humid periods characterized by increased water availability and vegetation cover.”

The caves selected for the study, located in the Al-Sulb Plateau, northeast of Riyadh, had been identified by the Saudi Geological Survey.




The Saudi Geological Survey (SGS) says there are over 150 caves recognized for their remarkable scientific significance in Saudi Arabia. (SPA)

“What drew us to this site was the fact that the modern landscape there is hyper arid, yet in the caves we see lots of evidence of stalactite and stalagmite growth,” said Markowska. “This means that it was wetter in the past because these just don’t form under the modern conditions.”

For “conservation reasons,” the paper gives only the general locations of the caves. However, the precise coordinates are available to some professional organizations and researchers from the Saudi Heritage Commission and the Saudi Geological Survey.

The story told by the 22 speleothems collected from the seven cave systems, all found within a 10 km radius, is an extraordinary one. Analysis of the samples has revealed a series of humid episodes over four distinct periods — between 0.86 and 1.37 million years ago (Ma), 2.01 and 2.29 Ma, 3.16 and 4.10 Ma, and 6.25 and 7.44 Ma.

This last humid episode occurred during what geologists classify as the Late Miocene. This is the period from which numerous fossils found further south, in the UAE, date — the remains of animals such as elephants, hippopotamuses, crocodiles, antelopes, hyenas and large carnivores, including saber-toothed cats, which have been unearthed in the Western Region of the emirate of Abu Dhabi.

These animals flourished there, according to a summary of decades of research published in 2012, thanks to “a very large river system flowing slowly through the area, along which was flourishing vegetation, including large trees.”

That river system may well have flowed from the interior of Arabia — and the fresh evidence from the caves northeast of Riyadh suggests the possibility that it was rainfall here that fed it.




Monika Markowska in the lab at Northumbria University. (Supplied)

“There is evidence in Arabia of rivers in the past, and certainly in the UAE fossils have been found where a river channel once ran,” said Markowska.

“But rivers can have very distant origins and the big thing about our paper is that for the first time we were able to determine that there was rainfall specifically in the center of the desert — evidence of actual rainfall in that area, rather than humidity from rivers that were sourced from distant locations.

“Before now, we knew a little bit about what was going on in the south of Arabia, that there were numerous humid phases going back over the past 1.1 million years. But we’ve been able to push that back to 8 million years, and this is for the center of the desert, where there was really no information before.”

The importance of this discovery is highlighted by the vast well of international specialist knowledge upon which the study drew. This is reflected in the list of the paper’s 31 co-authors, who include researchers and specialists from universities in the UK, Germany, Switzerland, Australia and the US.

It also includes the College of Tourism and Archaeology at King Saud University in Riyadh, the Kingdom’s Heritage Commission, Geotourism Department and the Saudi Geological Survey.

The paper thanks Prince Badr bin Abdullah bin Farhan Al-Saud, the Saudi minister of culture, for giving his permission for the research to be carried out, and acknowledges the vital role of the Heritage Commission in providing logistical and technical field support.




Prince Badr bin Abdullah bin Farhan, culture minister of Saudi Arabia. (SPA)

So far, as the paper makes clear, the “vertebrate fossil record of Arabia is scant,” with remains found only in two principal locations: The sandstone and mudstone Baynunah Formation in the UAE and the Nefud Desert in northwestern Saudi Arabia.

The fossils in the Nefud are “only” about 500,000 years old, and 6 million years younger than those from the Baynunah Formation, currently the only site where animal remains dating from the Late Miocene have been found.

But, said Markowska, the lack of fossil evidence from the same period in central Arabia “doesn’t necessarily mean there wasn’t fauna there at that time, but only that we haven’t found them yet.”

And, as the paper concludes, “considering our findings, it seems probable that movements between Africa and Eurasia would have taken place through the Arabian Peninsula, which, during humid phases, was likely characterized by well-watered grasslands and woodlands.”

Many of the animal species identified from fossilized remains in the UAE “would have been well suited for life in (central) Arabia during the wet episodes identified in our speleothem record. The scant fossil record aside, we suggest that Arabia probably acted as a hitherto unrecognized but important crossroad for biogeographic exchange between Africa and Eurasia over the past 8 million years.”

The researchers add that “the nature of these exchanges, and the exact role of Arabia in these, may only be elucidated with an improved fossil record.”

For now, a more pressing piece of research is underway, for the stalagmites of Saudi Arabia have more secrets to divulge.




Stunning view of Ain Heet cave, located in a mountain called Al-Jubayl in a small village in Wadi Al-Sulay, Riyadh.  Ain Heet is named after its entrance, which resembles the shape of the eye. The cave is formed with limestone. (AN file photo)

Finding out exactly what plants and trees thrived during the wet periods over the past 8 million years is key to understanding what species of herbivorous mammals — and, therefore, the meat-eaters that preyed upon them — might have existed in the once greener, lusher Saudi Arabia.

“This vegetation issue is our big next research question,” said Markowska.

“We have been able to identify these humid periods, and to identify what the dominant mechanisms for causing them were — basically, more moisture coming up from the south, during monsoon seasons. But we’re also very interested in this vegetation story.”

As speleothems grow, “they trap tiny amounts of pollen within their structure, and now we’re going to see if we can extract some ancient pollen from the speleothems, which is a technique we specialize in at Northumbria.”

This is a painstaking effort, “which involves a lot of microscope work. You extract the material, put it on a microscope slide and then count and identify the different pollen grains you find. I work with other colleagues who are experts on (ancient) pollen, and together I think we should be able to unwrap this other side of the story.”
 

 


Saudi Arabia condemns Israeli minister’s call for sovereignty over occupied West Bank

Updated 02 July 2025
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Saudi Arabia condemns Israeli minister’s call for sovereignty over occupied West Bank

  • Kingdom’s foreign ministry said the move would violate international laws

RIYADH: A government minister’s threat for Israel to apply full sovereignty over the occupied West Bank was strongly condemned by Saudi Arabia on Wednesday.

The Ministry of Foreign Affairs said the Kingdom “condemned and denunciated” the statement made by the Israeli official calling for the imposition of sovereignty over the Palestinian territory.

Such action would be a violation of international law, the statement said. Saudi Arabia rejects any attempts to expand settlements on Palestinian land, the ministry added, while reiterating the Kingdom’s position on the importance of Israel abiding by international resolutions.

The statement followed comments from Israel’s Justice Minister Yariv Levin saying “the time has come” for Israel to apply sovereignty across the West Bank.

Israel occupied the West Bank and East Jerusalem in 1967 and has built dozens of settlements, deemed illegal under international law, across the territory.

The Saudi foreign ministry offered its support for the Palestinian people in restoring their legitimate rights and in establishing a Palestinian state on the 1967 borders, with East Jerusalem as its capital.

 


Saudi ministry recalls faulty chargers over fire risk

Updated 02 July 2025
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Saudi ministry recalls faulty chargers over fire risk

RIYADH: Saudi Arabia’s Ministry of Commerce has announced the recall of 88,518 Anker portable chargers across multiple models due to a potential internal electrical short circuit that may cause overheating and pose a fire risk.

The ministry urged consumers to immediately stop using the affected products and contact Anker at the toll-free number 8008500030 to arrange a replacement or full refund, the Saudi Press Agency reported on Wednesday.

Consumers can check if their device is included in the recall and start the replacement or refund process by visiting anker.com/mmrc2506.

Users are also advised to verify the model number of their charger against the list of affected products on the Defective Products Recall Center website ecalls.sa.

The ministry reaffirmed its commitment to consumer safety and stressed the importance of promptly addressing product defects to prevent potential hazards.


GCC passports departments chiefs hold meeting

Updated 02 July 2025
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GCC passports departments chiefs hold meeting

Gulf Cooperation Council Secretary-General Jasem Albudaiwi participated in the 39th Meeting of the Directors-General of Passports of the GCC countries, held on Wednesday at the headquarters of the General Secretariat in Riyadh.

During the meeting, he reviewed the latest developments, including the Gulf visa project.

The passport departments of the interior ministries of GCC countries, through a series of joint meetings, are making efforts to launch a unified tourist visa project in the near future, the General Secretariat said in a report.

“Everyone is working as one team to keep pace with technological developments and security requirements in a world characterised by rapid change,” Albudaiwi said.


Saudi FM discusses regional developments in call with US secretary of state

Saudi Foreign Minister Prince Faisal bin Farhan held a phone call with his US counterpart State Marco Rubio on Wednesday. (AFP)
Updated 02 July 2025
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Saudi FM discusses regional developments in call with US secretary of state

RIYADH: Saudi Foreign Minister Prince Faisal bin Farhan held a phone call with his US counterpart Secretary of State Marco Rubio on Wednesday, Saudi Press Agency reported. 

During the call, Prince Faisal and Rubio reviewed US-Saudi relations and ways to enhance the strategic partnership between their countries. The latest regional and international developments were also discussed. 


Saudi delegation in Tokyo for talks on GCC-Japan free trade agreement

Updated 02 July 2025
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Saudi delegation in Tokyo for talks on GCC-Japan free trade agreement

  • Trade volume between Kingdom, Japan reached $36bn in 2024
  • Saudi team oversees and monitors progress of trade negotiations

TOKYO: Farid bin Saeed Al-Asali, the General Authority for Foreign Trade’s deputy governor for international agreements and organizations, is in Tokyo to lead the Kingdom’s delegation in the second round of negotiations on the free trade agreement between the GCC and Japan, which began on June 30 and will run until July 4.

According to GAFT, the Saudi negotiating team includes nine technical teams focused on goods, services, investment, e-commerce, intellectual property, and government procurement.

Comprising 46 government agencies, the teams prepare the Kingdom’s positions on negotiations and proposals within the World Trade Organization and free trade agreements, and submit relevant reports to the negotiating team.

In 2024, the trade volume between Saudi Arabia and Japan reached about $36 billion. The most significant exports from the Kingdom were mineral products and organic chemical products. In contrast, the primary imports from Japan included automobiles and automotive components, as well as machinery and mechanical tools.

Overall, Saudi Arabia’s exports totaled about $28 billion, while imports amounted to around $8 billion.

The Saudi team oversees and monitors the progress of trade negotiations to ensure they align with the Kingdom’s trade objectives and policies. Additionally, the team participates in the negotiations to incorporate the Kingdom’s positions, making their role integral to the process.

The General Authority for Foreign Trade aims to enhance trade gains, strengthen global presence, and engage with international organizations for sustainable development. The authority plays a crucial role in negotiations, representing the Kingdom’s interests and ensuring trade agreements align with its objectives.