Publication Date:
2020-12-21
Description:
We detail the Kamil crater (Egypt) structure and refine the impact scenario, based
on the geological and geophysical data collected during our first expedition in February
2010. Kamil Crater is a model for terrestrial small-scale hypervelocity impact craters. It is an
exceptionally well-preserved, simple crater with a diameter of 45 m, depth of 10 m, and rayed
pattern of bright ejecta. It occurs in a simple geological context: flat, rocky desert surface, and
target rocks comprising subhorizontally layered sandstones. The high depth-to-diameter ratio
of the transient crater, its concave, yet asymmetric, bottom, and the fact that Kamil Crater is not part of a crater field confirm that it formed by the impact of a single iron mass (or a tight cluster of fragments) that fragmented upon hypervelocity impact with the ground. The circular crater shape and asymmetries in ejecta and shrapnel distributions coherently indicate a direction of incidence from the NW and an impact angle of approximately 30 to 45 . Newly
identified asymmetries, including the off-center bottom of the transient crater floor downrange, maximum overturning of target rocks along the impact direction, and lower crater rim elevation downrange, may be diagnostic of oblique impacts in well-preserved craters. Geomagnetic data reveal no buried individual impactor masses 〉100 kg and suggest that the total mass of the buried shrapnel 〉100 g is approximately 1050–1700 kg. Based on this mass value plus that of shrapnel 〉10 g identified earlier on the surface during systematic search, the new estimate of the minimum projectile mass is approximately 5 t.
Description:
Published
Description:
1842–1868
Description:
3.8. Geofisica per l'ambiente
Description:
JCR Journal
Description:
restricted
Keywords:
Impact craters
;
geophysical survey
;
iron meteorite
;
impact scenario
;
04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous
;
04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques
;
04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
