Edeowie glass

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Edeowie glass is a slag-like, opaque, locally-abundant natural glass found as vesicular free forms or sheet-like/ropy masses. It is located throughout a semi-continuous swath in baked pod-like clay-bearing sediment, about 55 km long and 10 km wide along the western side of the Flinders Ranges near Parachilna, South Australia and Lake Torrens. The region in which this glass is found is mostly restricted to concentrations correlated to the ancient shoreline terrace sequence at the locality. It is typically black in appearance, but can occur as variegated grey-green with various streak-like impurities. Pale grey and red-brownish surfaces can be caused by chemical weathering (oxidation, mineralization) and devitrification.[1][2][3]

Origin[edit]

An origin for Edeowie glass has been assigned to either lightning strikes, or hypervelocity impact by one or several asteroids or comets. Many of its notable features, such as planar deformation features (PDFs) in quartz crystals found within and associated with Edeowie glass, are recognized to have been caused by pressures only exerted by such events capable of rapid shock metamorphism.[1][2][4][5]

Interval of formation[edit]

Edeowie glass yields dates spanning 0.67-0.07 mya (~670,000-70,000 BP), but some outlier dates are as recent as the middle Holocene.[1][2]

See also[edit]

References[edit]

  1. ^ a b c Haines, P.W., R.J.F. Jenkins, and S.P. Kelley, 2001, Pleistocene glass in the Australian desert: The case for an impact origin. Geology. v. 29, no. 10, pp. 899-902.
  2. ^ a b c Macdonald, F.A., K. Mitchell, and S.E. Cina, 2004, Evidence for a Lightning-Strike Origin of the Edeowie Glass. 35th Lunar and Planetary Science Conference, March 15–19, 2004, League City, Texas, abstract no.1406.
  3. ^ Gifford, A. C., 1999, "Clay soil fulgurites in the Eastern Goldfields of Western Australia" (PDF).  Journal of the Royal Society of Western Australia, 82:165-168, 1999
  4. ^ "Lightning-induced shock lamellae in quartz". Ammin.geoscienceworld.org. 2015-07-01. Retrieved 2015-08-16. 
  5. ^ Melosh, H.J. (2017). "Impact geologists, beware!". Geophysical Research Letters. 44 (17): 8873–8874. Bibcode:2017GeoRL..44.8873M. doi:10.1002/2017GL074840. 

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