ISS Captures Striking View of Libya’s Rare Ringed Mountains: The Geological Story Behind Jabal Arkanu

A recently released image from the International Space Station (ISS) has offered one of the clearest views yet of Jabal Arkanu, a remote ring-shaped mountain complex in southeastern Libya. The photograph highlights a geological formation once mistaken for a pair of meteorite craters but now recognized as a rare volcanic structure shaped by Earth’s internal forces.

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A Dramatic Landscape Carved by Ancient Magma

Rising abruptly from pale desert plains, Jabal Arkanu—also referred to as Arkenu—is part of an isolated cluster of dark, rocky mountains near the borders of Egypt and Sudan. The region is so arid that it receives only 1–5 millimetres of annual rainfall, according to long-term data from NASA and the Japan Aerospace Exploration Agency’s Tropical Rainfall Measuring Mission (TRMM).

The new ISS photograph, taken on September 13, 2025, reveals sweeping shadows cast across the desert and emphasizes the massif’s steep relief. The mountain reaches about 1,400 meters above sea level, standing roughly 800 meters above the surrounding sands.

For decades, scientists believed the mountain’s near-perfect circular rings were produced by ancient meteorite strikes. But field expeditions and geological surveys tell a different story. Researchers have determined that the concentric rings formed when multiple pulses of magma intruded upward, pushing into surrounding sedimentary layers and cooling into igneous rocks such as basalt and granite.

The central portions of the ring complex appear slightly tilted toward the southwest, a detail visible in the ISS image. North of the main structure lies a “cap” made of layered sandstone, limestone, and quartz, further evidence of the site’s long and complex geological history.

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Inside One of the Sahara’s Harshest Zones

The image captured by a crew member of ISS Expedition 73 using a Nikon Z9 camera and an 800mm lens shows fine surface details rarely observed from orbit. The desert floor around Arkanu is littered with large boulders, pebbles, and fan-shaped sediment streams that spill outward from the mountain’s slopes. Tall dune fields stretch beyond these rock patterns, shaped by relentless winds.

Even within this barren terrain, two wadis—dry river channels—cut through the mountain, though they carry water only during rare rain events. Slightly higher rainfall measurements of 5–10 mm per year near Arkanu may be attributed to minor orographic effects, where elevated terrain enhances moisture condensation.

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Why This Image Matters

NASA’s Earth Science and Remote Sensing Unit and the ISS Crew Earth Observations Facility, which released the image, emphasize that documenting such landscapes helps scientists track desertification patterns, geological evolution, and regional climate behavior in one of the least accessible parts of the world.

Earth-observation specialist Katherine Hanson, who compiled the report for NASA, notes that high-resolution astronaut photography offers “an unmatched perspective for analyzing large geological structures that are difficult to map from ground level.”

Beyond scientific value, detailed imagery of these formations contributes to regional mapping, supports environmental research, and helps maintain global archives of remote geological landmarks.