Archaeologists are mystified by ancient “gates” in Saudi lava fields

For almost a century, aerial photographers have been documenting mysterious, millennia-old structures built from low walls of stone in the rocky lava fields, known as harrat, in Syria, Jordan, and Saudi Arabia. This desert region, blistered with volcanic mounds, is nearly devoid of life. But seen from above, the barren ground is covered with massive, interlocking geoglyphs that take the form of abstract arrow shapes called "kites" and rough rectangles called "gates."

University of Western Australia archaeologist David Kennedy became interested in the structures after discovering how easy they were to track using Google Earth. He'd seen some of the kites while doing fieldwork in Jordan and realized that the structures continued into Saudi Arabia. "We would have loved to fly across into Saudi Arabia to take images. But you never get the permission,” he told The New York Times. “And then along comes Google Earth.” Now Kennedy has a paper about the rectangular gate structures in a forthcoming issue of Arabian Archaeology and Epigraphy.

Since 2004, a group of Saudi amateur archaeologists calling themselves The Desert Team (Fariq Al Sahra) has been exploring the geoglyph sites on the ground. Neurologist Abdullah Al-Saeed, part of The Desert Team, told the Times that it wasn't until 2008 that he looked at the sites using Google Earth and grasped the significance of what they had discovered. He and his colleagues keep a detailed photographic record of the kites and gates on their website. They've discovered that most of the geoglyphs are made from relatively low stone walls, sometimes punctuated with round "rooms" whose walls are higher. One hypothesis about the kites is that hunters herded animals into them for easy slaughter, but the Desert Team notes that the walls would have been too low to fence the animals in.

Kennedy believes the geoglyphs were built by nomads, perhaps the ancestors of Bedouins who live in the area today. They could be up to 9,000 years old, but further study is needed to determine exact dates. What's clear is that they were built over centuries at a time when volcanoes were active in the region; some of the walls are covered in lava from eruptions after they were built. Most of the gates are made from walls that are roughly 150 to 500 feet long, and the longest stretches almost 1,700 feet.

In his paper, Kennedy writes:

The lava fields are often rich in archaeological remains, implying a moister past and more abundant vegetation, and recent fieldwork identifying larger settlement sites supports this notion...As in the much better explored lava field of Jordan there are many thousands of stone-built structures which are collectively known to Bedouin as the 'works of the old men.'

In some ways, the gates and kites resemble the geoglyphs of the Nazca region in Peru, often called the Nazca lines. These pale lines were created by people who scraped through the dark surface layer of desert rock. From the air, they look like large abstract designs and animals. No one is certain who made them, or why.

Neither the Desert Team nor Kennedy and his colleagues have any idea what the harrat geoglyphs mean. Kennedy doesn't think they were used as burial mounds or for hunting. They don't seem like structures that people could live in. It's possible they were purely symbolic, used in rituals whose meaning has been lost to time.

Listing image by Google Earth