Ancient darkness has "enveloped" 44,000 km² of the Sahara, visible from space. What caused this shadow? (See photos)

A massive patch of black petrified lava, expelled through the Sahara Desert over millions of years, resembles an ancient eerie shadow speckled with gold. Researchers have unveiled a stunning composite image created from satellite photographs taken over the past three years, as reported by Live Science.

According to scientists from the U.S. Geological Survey, the dark mass, also known as the Haruj volcanic field, spans approximately 44,000 square kilometers in central Libya and contains around 150 extinct volcanoes, ranging from small vents and pipes to larger shield volcanoes. Researchers found that some of these volcanic rocks date back as far as 6 million years, while others were formed from much more "recent eruptions" just a few thousand years ago.

Experts from the Smithsonian National Museum of Natural History explain that the dark color of the petrified lava gives the field a smooth and flat appearance, but in reality, it is far from flat. Multiple eruptions in the region have caused layers of rock to stack upon one another. This area is also dotted with raised vents and at least 30 cones that rise more than 100 meters high. Notably, the highest peak here reaches 1,200 meters above sea level.

The satellite photo recently released by scientists represents a "pixel mosaic" and was created using a computer program that sorts multiple images of the same location pixel by pixel. As a result, researchers were able to produce a final image free from obscuring elements such as clouds or dust storms.

The model used by the scientists also selected pixels where patches of sand settled between the gaps in the lava, capturing sunlight—this created golden specks scattered across the dark field in the image.

It is known that most volcanoes are formed along fault lines that cross tectonic plates of the Earth—these areas are where the Earth's crust is the weakest, allowing magma from the mantle to easily rise to the planet's surface.

At the same time, the Haruj volcanic field in the Sahara is not situated near any known fault lines. Instead, scientists believe that the lava here was lifted from the mantle by a tide of hot rocky material that created a magma reservoir above the field. As a result, lava from the Haruj volcanoes slowly bubbled and seeped from numerous vents in the field, similar to the ongoing eruptions occurring at Hawaii's Kilauea volcano, rather than being ejected through explosive eruptions.

Some researchers also believe that the Haruj field actually consists of two separate volcanic fields:

• Al-Haruj al-Aswad, located in the north and containing much older lava;
• Al-Haruj al-Abiad, located in the south and formed quite recently.

However, scientists acknowledge that it is currently difficult to determine where the boundaries of these fields truly begin and end.