Gebel Kamil: The iron meteorite that formed the Kamil crater (Egypt)

Abstract

Abstract-The 45 m in diameter Kamil impact crater was formed <5000 yr ago in the eastern Sahara, close to the southern border of modern Egypt. The original features of this structure, including thousands of fragments of the meteorite impactor, are extremely well preserved. With the exception of a single 83 kg regmaglypted individual, all specimens of Gebel Kamil (the iron meteorite that formed the Kamil crater) are explosion fragments weighing from <1 g to 34 kg. Gebel Kamil is an ungrouped Ni-rich (about 20 wt% Ni) ataxite characterized by high Ge and Ga contents (approximately 120 lg g)1 and approximately 50 lg g)1 , respectively) and by a very fine-grained duplex plessite metal matrix. Accessory mineral phases in Gebel Kamil are schreibersite, troilite, daubre´elite, and native copper. Meteorite fragments are cross-cut by curvilinear shear bands formed during the explosive terrestrial impact. A systematic search around the crater revealed that meteorite fragments have a highly asymmetric distribution, with greater concentrations in the southeast sector and a broad maximum in meteorite concentration in the 125-160°N sector at about 200 m from the crater rim. The total mass of shrapnel specimens >10 g, inferred from the density map compiled in this study is 3400 kg. Field data indicate that the iron bolide approached the Earth's crust from the northwest (305-340°N), travelling along a moderately oblique trajectory. Upon hypervelocity impact, the projectile was disrupted into thousands of fragments. Shattering was accompanied by some melting of the projectile and of the quartzarenite target rocks, which also suffered shock metamorphism.

The Wabar impact craters, Saudi Arabia, revisited

“…The presence of strongly shattered iron meteorite fragments (“shrapnels”) together with meteorites displaying regmaglyptic surfaces, unaffected by the forces of high‐velocity impact, has recently been reported from the Kamil crater in Egypt (D'Orazio et al. ). These authors also concluded that subparallel, undulating fractures in iron fragments are related to the terrestrial impact, whereas irons displaying regmaglyptic surfaces arrived as individual, more strongly decelerated objects.…”

Shock metamorphism and impact melting in small impact craters on Earth: Evidence from Kamil crater, Egypt

“…Thousands of shrapnel pieces up to 34 kg in mass, formed through fragmentation upon hypervelocity impact of the Gebel Kamil iron meteorite, were found concentrated due southeast of the crater with a broad concentration maximum at approximately 200 m from the crater rim (D'Orazio et al. ).…”

“…During this campaign a series of target rock samples representing the crater wall and ejecta were collected with the aim of investigating the shock metamorphism and impact melting induced in the local rocks by the impact of the small (5–10 t) Gebel Kamil Ni‐rich ataxite (D'Orazio et al. ). In this work, we present a detailed description of the shock features found within these samples.…”

The extremely reduced silicate‐bearing iron meteorite Northwest Africa 6583: Implications on the variety of the impact melt rocks of the IAB‐complex parent body

“…; Wasson and Kallemeyn ; D'Orazio et al. ). The high Ge/Ga ratio and the low Ni/Ir ratio of Repeev Khutor, IIF iron group (16.6 and 4.8, respectively), exclude any relationship between NWA 6583 (Ge/Ga = 2.4 and Ni/Ir = 94.7) and the IIF irons group.…”