The Kamil Meteor Crater (Gilf Kebir region, Egypt)

A rare sample for small-scale meteorite impact craters on Earth

Norbert Brügge, Germany
Dipl.-Geol.

The so named "Kamil Crater" was located during a Google Earth "low flight" (1,000 m above ground level) by Vincenzo De Michele (Istituto Gemmologico Italiano).

The necessary on-site verification of the Kamil Crater was undertaken in the February 2009 expedition by members of Zerzura Club: Massimo Cammelli, Lorenzo De Cola, Vincenzo de Michele, Mario Di Martino, Adriano Furlani, Giancarlo Negro, Gil Ruozzi e Tommaso Vannini.

The thousands of iron meteorite (ataxite rich in nickel) specimens found scattered within the crater and in the surrounding area confirmed the meteoritic impact origin of the crater. The crater is locate at Djebel Kamil, south of Gilf Kebir nearby the Sudanese border. The crater is 45 m in diameter.

A Italian-Egyptian geophysical expedition was then carried out in February 2010 in order to describe this model impact structure and to collect most meteorites specimens in the crater area. The Team identified 5,178 meteoritic fragments totaling 1.7 tons — the biggest single specimen weighs 83 kg.

The Kamil Meteor Crater is not related to the widespread crater-shaped structures in the Gilf Kebir region as well as in the Djebel Kamil/northern Sudan. These are much older (28.2 to 26.7 million years) and are of subvolcanic origin.

Published in Meteoritical Bulletin, no. 98, in preparation (2010). Authors are:

L. Folco1, M. Di Martino2, A. El Barkooky3, M. D'Orazio4, A. Lethy5, S. Urbini6,
I. Nicolosi6, M. Hafez5, C. Cordier1, M. van Ginneken1, A. Zeoli1, A. M. Radwan5,
S. El Khrepy5, M. El Gabry5, M. Gomaa5, A. A. Barakat7, R. Serra8, M. El Sharkawi3

1 Museo Nazionale dell'Antartide Università di Siena, 53100, Siena, Italy.
2 Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Torino, 10025 Pino Torinese, Italy.
3 Department of Geology, Faculty of Sciences, Cairo University, Giza, Egypt.
4 Dipartimento di Scienze della Terra, Università di Pisa, 56126 Pisa, Italy.
5 National Research Institute of Astronomy and Geophysics, Helwan, Egypt.
6 Istituto Nazionale di Geofisica e Vulcanologia, 00143 Roma, Italy.
7 Egyptian Mineral Resources Authority, Abassiya, Cairo, Egypt.
8 Dipartimento di Fisica, Università di Bologna, 40126 Bologna, Italy.

Location: 22°01'06''N / 26°05'16''E

 
 First details:                           http://tin.er.usgs.gov/meteor/metbull.php?code=52031

 Qick status report:               Online July 22, 2010 by Science Express, DOI: 10.1126/science.1190990

 MNA website:                         http://www.mna.it/hosts/Kamil/index.htm
 Geology, 39, 2, Febr. 2011:  Online January 05, 2011 by Geology, DOI: 10.1130/G31624.1
 

Geophysicists at work in the Kamil Crater
 to gather detail information  of the crater morphology through Ground Penetrating Radar profiles

The biggest meteorite specimen found 230 m due north of the crater showing regmaglypts

Polished and etched internal surface of shrapnels showing schreibersite inclusions

Field photograph: Impact melt glass at the Kamil Crater

 The geological age of the target-rocks

The Djebel Kamil is known throughout the Gilf Kebir region for the outcrop of Precambrian Basement. According to geological maps are some prominent sandstone hills in the Djebel Kamil of Paleozoic origin. The habitus of the sandstones is similar to the sandstones of the southern Gilf Kebir (Aqaba Passage, Kemal-el-Din Plateau), and therefore as there also of Devonian age. The Gilf Kebir and Djebel Kamil are the remnants of a once uniform blanket of Devonian sandstones. Its are on a uplifted block of the Basement, which is bounded by faults. Since the end of the Devonian only erosion took place, interrupted only by a  fluvial sedimentation in the Lower and Middle Cretaceous period. These sediments have filled up valleys between the eroded blocks of paleozoic sandstones. Thicker deposits of the Cretaceous period are found in the Abu Ballas region, in the east of a presumed main-fault, where the Basement and Paleozoic sandstones are about 500 m deeper.

Therefore, the target rocks of the Kamil Meteorite is the filling of Cretaceous layers in the erosional valleys between the Devonian sandstone remnants.

Lithostratigraphic profiles (published by WYCISK, 1984) document the sequences of fluvial sandstones and interbedded nearshore sediments with channel-fill facies. The lower part should represent the "Gilf Kebir Formation”. Sedimentation starts with the "upper part of the Gilf Kebir Formation", which consists of intercalations of fluvial braided and minor tidal-channel deposits, overlaying a thin basal conglomerate.
The section contains fluvial, medium to coarse-grained sandstones with single conglomeratic layers at the scoured base of the sequence. Small-scale tabular cross-bedding is the main facies in these cycles, trough cross-sets occur infrequently.
The fluvial deposits are interbedded by nearshore sediments ranging from 2-6 meters in thickness. This facies consists of grey medium to fine-grained sandstones with silt and shale intercalations. Wavy, flaser-and-lenticular bedding prevail in the lower part of the coarsening-upward sequence. This facies in particular is overlain by massive or irregular horizontally laminated sandstones, containing shale intraclasts, scattered quartz granules and isolated vertical burrow tubes. Burrows of Spongeliomorpha up to 15 cm in diameter occur in an intensely bioturbated sandstone.
The upper shore face deposition is characterized by medium to coarse-grained well sorted sandstones, with laminated layers, low angle and trough cross-beds. Vertical burrow tubes probably made by crabs are present throughout the facies.