Trou au Natron

Trou au Natron and Tousside ( south and Caldera are above)

The Trou au Natron (also: Doon Orei ) is a caldera in the highest and certainly most remote mountain massif of the Sahara, the Tibestigebirge in Chad. The " Natronloch " takes its name from the large, snow white shimmering crust of sodium carbonate, line the parts of the caldera. The configuration of the floor plan, which is not circular, indicates a multiphase crater formation.

Geographical location

The Trou au Natron was at the southern foot of the 3265 m high Tarso Toussidé and is located in the northwestern part of the Tibesti Mountain Range ( volcanic range ), which will be completed in the southeast of the highest elevation of the Tibesti Mountains, the 3415 m high active Emi Koussi. In the slipstream of the Trou au Natron is the Great Sandy Desert of Bilma that belongs to the Ténéré. In the West, pull out to the dunes Niger Aïr Mountains. To the north is the "dead " Tenere you Tufessasset. Approx. 500 km north at the extreme northern edge of the Tibesti is the impressive Waw an Namus -.


It is still controversial among scientists whether the caldera of the volcano is the result of a collapse or was due to pyroclastic activity. The crater has a diameter of almost eight kilometers and a depth of 950 meters. He gave to his creation is itself the ground for the emergence of smaller volcanoes in its crater interior. The one-time up to 500 m deep lake was subject to discounts and desiccation until today's salt marshes were left.