Darwin Crater

False-colour Landsat image of Darwin Crater (arrowed); screen capture from NASA World Wind
Oblique false-colour Landsat image of Darwin Crater (arrowed) draped over digital elevation model; screen capture from NASA World Wind
There is also a Darwin crater on the moon and a Darwin crater on Mars

Darwin Crater is a suspected meteorite impact crater in Western Tasmania.

It is expressed as a rimless circular flat-floored depression, 1.2 kilometres (0.75 mi) in diameter, within mountainous and heavily forested terrain 26 kilometres (16 mi) south of Queenstown. It lies east of the West Coast Range and the former North Mount Lyell Railway formation, and just within the Franklin-Gordon Wild Rivers National Park.

The crater was discovered by the geologist R. J. Ford in 1972, after a search for the source of Darwin glass,[1] an impact glass found over more than 400 square kilometres (150 sq mi) of southwestern Tasmania.[2] Geophysical investigations and drilling have shown that the crater is filled with up to 230 metres (750 ft) of breccia capped by Pleistocene lake sediments.[3][4] Although definitive proof of an impact origin of the crater is lacking, the impact hypothesis is strongly supported by the relationship of the glass to the crater, as well as the stratigraphy and deformation of the crater-filling material.[4]

If the crater is indeed the source of the glass, the age of Darwin Crater is 816,000 ± 7,000 years—the age of Darwin glass as determined by argon dating methods.[5]

A 2004 thesis from the University of Tasmania was focused specifically on the glass material origins [6]

Carbonaceous inclusions have been found for the first time in Darwin glass: these have been shown to be biomarkers which survived the Darwin impact and are representative of plant species in the local ecosystem — including cellulose, lignin, aliphatic biopolymer and protein remnants.[7]


External links

References

  1. ↑ Ford, R.J. (1972). "A possible impact crater associated with Darwin glass". Earth and Planetary Science Letters. 16 (2): 228–230. Bibcode:1972E&PSL..16..228F. doi:10.1016/0012-821X(72)90194-X.
  2. ↑ Howard, K.T.; Haines, P.W. (2003). "Distribution And Abundance Of Darwin Impact Glass" (PDF). Third International Conference on Large Meteorite Impacts.
  3. ↑ Fudali, R.F.; Ford, R.J. (1979). "Darwin glass and Darwin crater - A progress report". Meteoritics. 14: 283–296. Bibcode:1979Metic..14..283F.
  4. 1 2 Howard, K.T.; Haines, P.W. (2007). "The geology of Darwin Crater, western Tasmania, Australia". Earth and Planetary Science Letters. 260 (1–2): 328–339. Bibcode:2007E&PSL.260..328H. doi:10.1016/j.epsl.2007.06.007.
  5. ↑ Lo, C.H.; Howard, K.T.; Chung, S.L.; Meffre, S. (2002). "Laser-fusion 40Ar/39Ar Ages of Darwin Impact Glass". Meteoritics & Planetary Science. 37 (11): 1555–1562. Bibcode:2002M&PS...37.1555L. doi:10.1111/j.1945-5100.2002.tb00810.x.
  6. ↑ Howard, Kieren Torres (2004), Origin of Darwin glass, retrieved 1 December 2014
  7. ↑ Howard, K.T.; Bailey, M.J.; et al. (2013). "Biomass preservation in impact melt ejecta". Nature Geoscience. 6: 1018–1022. doi:10.1038/NGEO1996.

Coordinates: 42°18′15″S 145°39′27″E / 42.30417°S 145.65750°E / -42.30417; 145.65750

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