Short note: The Faya basin (N Chad, Africa) – A possible impact structure?

The Faya basin, an almost circular structure, has been discovered by remote sensing using Landsat and Shuttle Radar Topographic Mission (SRTM) data. It is centred on 18°11′ N and 19°34′ E, about 55 km ENE of the city of Faya (Largeau), and has a diameter of ∼2 km. The Faya basin is a singular geological feature that formed in sandstones of most likely Late Devonian age. As so far observed and interpreted in satellite imagery and digital elevation models, the Faya basin exhibits various structural features and the typical morphology of small, complex impact craters: an elevated rim surrounded by concentric faults, an annular depression, and a central topographic high. It is difficult to explain the formation of the Faya basin by common geological processes. No volcanic features are known in this area. Eroded magmatic intrusions and volcanic calderas should usually be different in size and shape, and should show an inhomogenic rock distribution on satellite images. Further, no salt diapirs, sinkhole structures, or glacial erosion features have been reported in this region. Therefore, we suppose that the Faya basin might have an impact origin, but final confirmation will require studies of rock samples from the structure.