Bodélé Depression
Bodélé Depression | |
|---|---|
Dust storm in the Bodélé Depression. This particular storm was blowing on the afternoon of 18 November 2004, when the Moderate Resolution Imaging Spectroradiometer (MODIS) flew over on NASA's Aqua satellite. The full-sized image has a resolution of 250 meters per pixel. | |
| Location | North Central Africa |
| Age | Few thousand years |
| Formed by | Drying up of Lake Chad |
The Bodélé Depression (pronounced [bɔ.de.le]), located at the southern edge of the Sahara Desert in north central Africa, is the lowest point in Chad. It is 500 km long, 150 km wide and around 160 m deep. Its bottom lies about 155 meters above sea level. The dry endorheic basin is a major source of fertile dust essential for the Amazon rainforest.
Dust storms from the Bodélé Depression occur on average about 100 days per year, one typical example being the massive dust storms that swept over West Africa and the Cape Verde Islands in February 2004. As the wind sweeps between the Tibesti and the Ennedi Mountains in Northern Chad, it is channeled across the depression. The dry bowl that forms the depression is marked by a series of ephemeral lakes, many of which were last filled during wetter periods of the Holocene.
Diatoms from these fresh water lakes, once part of the prehistoric Mega-Lake Chad, now make up the surface of the depression and are the source material for the dust, which, carried across the Atlantic Ocean, is an important source of nutrient minerals for the Amazon rainforest.