Congo Impact Crater ?
Thursday, March 11, 2010 7:42:37 AM
A new ring structure found in Central Africa (revealed by deforestation) could be one of the larger impact crater discovered in the last decade and one of the largest ever according to findings presented the Lunar and Planetary Science Conference in Texas, US, March 2010.
The ring structure is located in the Eastern Kasai province (R.D. Congo) and is centered at 3°37’50’’S, 24°31’00’’E, 37 km north of Wembo-Nyama. It is recognisable from satellite images for the perfect roundness of the ring. If the external rim of the thalweg is taken into account, the annulus has a total diameter of 36 km. The central part of the structure is irregular and about 50-60 m higher than the depression where the river flows.
The stratigraphy of the area, where the structure occurs, consists of a Precambrian Basement covered by the Karoo Supergroup of late Palaeozoic – Triassic age (~800 m thick), in turn overlaid by a Jurassic-Cretaceous sedimentary succession. The whole succession is characterized by continental deposits (sandstones to clay, tillite and conglomerates) and is buried by Plio-Pleistocene fluvial and colluvial deposits. The topography indicates a diameter of the structure from 36 to 46 km, but the outer ridge is not well developed, likely deeply weathered and eroded by tropic climate.
- The stratigraphy does not match a saltdiapir origin of the ring.
- The diameter is too large for a kimberlitic pipe.
- A caldera structure is excluded.
- A batolith is unlikely.
The authors conclude that an impact origin may be the more valuable solution, and their guess is that it was caused by a major impact event that happened during Cretaceous-Cenozoic time span.
The team will now have to travel to the region to carry out field studies, and examine rocks from the site for tell-tale signs associated with extraterrestrial impacts. Further studies will also be required to accurately determine an age for the ring, but it appears to post-date the Jurassic Period (younger than 150 million years).
A Google Earth file (.kmz) can be downloaded from the Google Earth Community.
The Ring Structure of Wembo-Nyama (Eastern Kasai, R.D. Congo): A Possible Impact Crater in Central Africa
G. Monegato, M. Massironi, E. Martellato
41st Lunar and Planetary Science Conference (2010), Abstract #1601
Hat tip to tweet from Chris Rowan of Allochthonous.