Gebel Kamil

East Uweinat Desert, Egypt
Find, 19.2.2009

Iron, ungrouped
Shrapnel, 2045 g
Size: 413,0 x 11,5 x 7,5 cm

History:
This iron meteorite was found in the East Uweinat Desert, Egypt. “Kamil Crater” was located during a Google Earth “low flight” (3,200 ft. above ground level). It is believed to have been formed by a 10-ton piece of iron travelling at more than 7,500 miles per hour.

The necessary on-site verification of the Kamil Crater was undertaken in the February 2009 expedition by members of Zerzura Club:The crater is located at Djebel Kamil, south of Gilf Kebir nearby the Sudanese border. The crater is 184 foot across and 50 foot deep. Thousands of iron meteorite specimens were found scattered within the crater and in the surrounding area. The remarkable discovery has led the scientists to conclude that metallic meteorite had a mass on the order of 10 tons and it did not break up in the atmosphere and instead it exploded when it reached the ground and produce a crater.

Although the precise date of the meteorite strike is yet to be determined, analysis of samples taken during the expedition has revealed that the meteorite strike could not have occurred more than 10 thousand years ago and could have potentially taken place less than a few thousand years ago.

A total of about 1600 kg of iron meteorite shrapnel (thousands of pieces), ranging in mass from < 1 to 35,000 g, plus a single 83 kg individual completely covered with well developed regmaglypts, was found in and around the 45 m diameter Kamil impact crater by an Italian-Egyptian geophysical team in February 2009 and February 2010. Approximately 800 kg of the total mass observed in the field (the regmaglypted individual inclusive) was recovered. The Kamil crater was identified by V. De Michele, former curator of the Natural History Museum in Milan, Italy. The geophysical survey was carried out within the framework of the "2009 Italian-Egyptian Year of Science and Technology".
The Gebel Kamil meteorites are different from many iron meteorites because it contains an unusually large amount of nickel. Most irons contain between 5-10% nickel but Gebel Kamil is loaded with 20%. This makes it a considerably rarer type of iron meteorite called an ataxite.

Physical characteristics:
A 634 g type specimen, measuring 88 × 70 × 55 mm, is flattened and jagged shrapnel with a rough, dark-brown external surface. The surface originally sitting in the desert soil shows some oxy-hydroxides due to terrestrial weathering.

Petrography:
(M. D’Orazio, DST-PI; Luigi Folco, MNA-SI) Etched sections show an ataxitic structure interrupted on a cm-scale by crystals of schreibersite, troilite and daubreelite enveloped in swathing kamacite. Kamacite spindles (20 ± 5 μm wide) nucleated on tiny schreibersite crystals. The spindles form small aligned clusters and are rimmed by taenite. The matrix is a duplex plessite made of approximately the same proportion of kamacite and taenite lamellae (1-5 μm in thickness) arranged in a micro-Widmanstätten pattern. Many sections show, particularly close to the external surface, shear dislocations offsetting the plessitic matrix and the crystals of the accessory phases by several millimeters.

Geochemistry:
Composition of the metal (ICP-MS; D’Orazio and Folco, 2003) is Co = 0.75, Ni = 19.8 (both in wt%), Cu = 464, Ga = 49, Ge = 121, As = 15.6, Mo = 9.1, Ru = 2.11, Rh = 0.75, Pd = 4.8, Sn = 2.49, Sb = 0.26, W = 0.66, Re = 0.04, Ir = 0.39, Pt = 3.5, Au = 1.57 (all in ppm).

Classification:
(M. D’Orazio, DST-PI; Luigi Folco, MNA-SI) Iron meteorite (ungrouped), Ni-rich ataxite, extensive shear deformation and low weathering.

Specimens:
Type specimens of approximately 15 kg and one section at MNA-SI; approximately 5 kg at DST-PI. Main mass of the recovered specimens at Egyptian Geological Museum (Mineral Resources Authority), Cairo, Egypt.

Specimen Description:
Shrapnel piece with nice desert patina.

Comments:
Gebel Kamil presents a rare crater forming iron meteorite.

References:
Meteoritical Bulletin Database