Dakhleh Glass - Impact Deposit

Alternate Names Dakhla glass
Coordinates 25° 26' 60" N; 29° 11' 24" E
Notes
  1. Dakhleh Oasis is a ~1200 km2 wind-ablated depression in the central Western Desert of Egypt
Country Egypt

Related Countries :
  1. Egypt
Region Western Desert
Date Confirmed 2007
Notes
  1. No typical shock metamorphic evidence. Evidence for impact comes from high CaO and Al2O3 content of glass (up to ~25 and 18 wt%, respectively), the presence of globules of immiscible calcite and pyrrhotite melt phases, shattered quartz grains, and fragments of silicified plant matter (Osinski et al., 2007) (Osinski et al., 2008)
Age (Ma) 0.145
Notes :
  1. (Renne et al., 2009)

Method :
  1. 40Ar/39Ar
Impactor Type Unknown

Advanced Data Fields

Notes

Local Language
N/A
Spherules
Unknown
Tektites
Unknown
Indivudual Glass Clasts
Yes
Source Crater
Unknown
Geology
Glass was found over an area of ~40 x 10 km. The glass appears to be associated with Middle Pleistocene lacustrine sediments. Occurs as a lag deposit on Pleistocene lacustrine sdiments and Taref Formation sandstone, and on or in Holocene pan sediments. The glass is typically black when fresh and greenish-grey when weathered and vary in the amoun tof vesicularity. Impressions of reed-like stems or leaves are found on the underside of some glass samples. Little movement/erosion following deposition.
  1. Osinski et al., 2007; Osinski et al., 2008
Other Shock Metamorphism
Unknown
  1. No diagnostic shock metamorphism evidence present
Shatter Cones
No
Planar Fractures
No
Planar Deformation Features
No
Diaplectic Glass
No
Coesite
No
Stisovite
No

References

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Gordon R Osinski, Henry P Schwarcz, Jennifer R Smith, Maxine R Kleindienst, Albert F C Haldemann, Charles S Churcher (2007) Evidence for a ∼200–100 ka meteorite impact in the Western Desert of Egypt, Earth and Planetary Science Letters 253(3), p. 378-388, url, doi:https://doi.org/10.1016/j.epsl.2006.10.039

G R Osinski, J Kieniewicz, J R Smith, M B E Boslough, M Eccleston, H P Schwarcz, M R Kleindienst, A F C Haldemann, C S Churcher (2008) The Dakhleh Glass: Product of an impact airburst or cratering event in the Western Desert of Egypt?, Meteoritics & Planetary Science 43(12), p. 2089-2107, John Wiley & Sons, Ltd, url, doi:10.1111/J.1945-5100.2008.TB00663.X

P R Renne, H P Schwarcz, M R Kleindienst, G R Osinski, J J Donovan (2010) Age of the Dakhleh impact event and implications for Middle Stone age archeology in the Western Desert of Egypt, Earth and Planetary Science Letters 291(1-4), p. 201-206, url, doi:10.1016/j.epsl.2010.01.014