Kebira Crater - Origin of Kebira Crater

Origin of Kebira Crater

Because it is based entirely on remote sensing data and the current lack of formally published field studies, ideas about the impact origin of the Kebira Crater remain unconfirmed and untested according to papers published in the formal scientific literature. In one paper, it and some other recently proposed impact structures are described as being "dubious." The Impact Field Studies Group's Impact Database (formerly Suspected Earth Impact Sites, SEIS) list rates this as improbable for an impact origin. This catalog notes that the observed circular area was visible in Google Earth as having a flat top in the center. They suggest that the flat tops indicates that the strata within the center of this feature is flat-lying and undisturbed. If this is an impact structure, the strata within the center of it would not be flat lying. Instead, the strata within it center would be complexly and distinctly folded, tilted, and faulted as a result of an extraterrestrial impact.

According to popular accounts, visitors to the Kebira Crater have repeatedly failed to find any evidence of an extraterrestrial impact. After the existence of a possible impact structure in early March 2006, several people quickly responded to the announcement by arranging to travel to the site. Two scientists arrived in Libya in March, and later informally published their findings: "ontinued north . . towards a large circular feature that was recently announced to be an 'impact crater' . . We drove past the 'central uplift' along its western edge, then drove into the central part. It is evident, that what is considered the 'central uplift' is in fact nothing more than an eroded outlier of the Gilf, the undisturbed horizontal bedding being clearly visible at all times. The circular shape appears to be pure coincidence, the whole feature is the result of drainage patterns and subsequent eolian erosion, there is nothing to suggest its impact origin." And "We were now in the crater area, looking at the western edge of the central uplift area of the 'crater'. What we saw were uniform horizontal layers of sedimentary rocks, undisturbed except by the processes of natural erosion. The jumbled, chaotic rock formation that we would expect to see in the central uplift area of a crater was not evident at all."

A study published in Meteoritics & Planetary Science reported a field investigation of the Kebira Crater area. After analyzing the presence/absence of several geologic features associated with impact craters, such as target rocks, breccias, pseudo-shatter cones, and circular morphology, the authors concluded: "here are no clear and unequivocal evidence supporting the impact origin of the circular structures in Glif Kebir region; until substantial evidence is produced, it's necessary to identify the origin of the craters in others endogenic geological processes." They proposed the most likely alternative source of the crater to be a hydrothermal vent, although they went on to say: "However, even this hypothesis is not fully satisfactory: probably these complex and peculiar features are the result of interaction between different geological process. At present, this hypothesis cannot be completely constrained; further investigations are necessary. Anyway, the lacking of clear evidences of a meteoritic impact and the geological framework of the investigated area, lead us to confirm the hydrothermal-volcanic hypothesis. They also concluded that the origin of the Kebira Crater needed further in situ investigations.