Mise en évidence de corps d'origine cosmique probable au sein de la formation de Carnot (République Centrafricaine)

Abstract

Two independent investigations, made on the Mesozoic fluvial Carnot Formation, yielded magnetic microspherules in borehole residues and a localized (270 m long) magnetic anomaly profile. The spherules are ferrous with sometimes traces of Al, Ti and Mn; their morphology is similar to the morphology of cosmic spherules (with mosaic, octahedral, spongy or with “Astrakhan coat”-like fabrics). The magnetic anomaly is related to a body buried at approximately 30–40 metres, i.e., in the Cretaceous Carnot Formation. This body could be modelled by a sphere or by an assemblage of dimensional polygons, with strong remanent magnetization. This indicates that the anomaly source has undergone a fusion and cooling process under the Cretaceous geomagnetic field. As there is no evidence of volcanic activity, this process is considered to be related to meteoritic falling. The magnetic spherules and the source of magnetic anomaly correspond to micrometeorites and meteorites which fell in the west of Central African Republic between Albian and Maastrichtian times. However, without geochronological data, it is not possible to indicate if the two perturbations are the result of the same extraterrestrial event or of two different events.