The Unique Qualities of Lake Iro in Chad: Beyond the Famous Sunglint Image

In the heart of south-eastern Chad, approximately 120 km from the border with the Central African Republic, lies Lake Iro. This vital resource for the local community serves as a permanent water source and provides fodder for cattle. Situated in the middle of an inland delta formed by the Bahr Salamat river, Lake Iro is unique in its semi-circular shape and approximately 12 km in diameter.

The geological formation of Lake Iro remains somewhat mysterious, with the specific fault responsible for its creation yet to be explicitly detailed. However, the formation of similar impact structures, such as the Tüttensee crater, suggests a localized fault or fracture zone beneath the surface, causing such lakes.

The Bahr Salamat river, which seems to go around the Iro lake depression, averages at 387 metres in altitude. Interestingly, the altitude of the river south of Lake Iro is only 40 metres higher than its altitude 160km to the west-south-west, indicating a possible regional uplift caused by the impact that formed Lake Iro. This uplift may have caused the Bahr to change its course to the south to avoid the uplifted region.

Lake Iro may be the largest extraterrestrial impact crater lake in Africa, though it is yet to be definitively proven. A group of scientists is heavily involved in tracking down impact craters on the African continent, including the ongoing study of the Velingara structure in Senegal.

A fascinating visual phenomenon associated with Lake Iro is sunglint. This occurs when the sun reflects off the lake's water with wavelets, resulting in blurred light. Sunglint can also be seen in satellite imagery, as well as from aeroplanes or the top of mountains, looking at water surfaces riddled by a breeze, in the direction of the sun.

The area around Lake Iro is not just a geological wonder but also a significant economic hub. The local community engages in fishing, with people producing dried smoked fish for export. The flat slope of the Bahr Salamat river south of Lake Iro contributes to the fertility of the land, making it suitable for agriculture.

The study of Lake Iro continues, with Pierre Rochette's mission to the lake supported by the University of N'Djamena in Chad, as well as the Institut de Recherche et Développement (IRD). The article was republished from The Conversation under a Creative Commons license.

As Africa has only 20 proven impact craters, corresponding to one tenth of the total proven craters on Earth, the discovery of Lake Iro as an impact crater would significantly add to our understanding of the continent's geological history. Since 2014, no new crater has been discovered in Africa, making the potential discovery of Lake Iro even more intriguing.