Tookoonooka - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 27° 12' 51" S; 142° 50' 10" E
Notes
  1. E Central Australia, Eromanga Basin in S.W. Queensland, Australia. Latitude and longitude are approximate.
Country Australia
Region Queensland
Date Confirmed 1989
Notes
  1. PDFs in quartz grains from breccia (Gorter et al., 1989).
Buried? Yes
Notes
  1. Occurred in a basin of continuous sedimentation. Buried by 880 m of sediment of Cretaceous and younger.
Drilled? Yes
Notes
  1. Drilled as an oil prospect by seven wells ~200 m of breccias in the central well.
Target Type Sedimentary
Notes
  1. Early Cretaceous sediments (mudstone, siltstone, sandstone) overlaying Ordovician basement. Impact penetrated to basement.
Sub-Type Mudstone, Sandstone, Siltstone
Apparent Crater Diameter (km) 66 km
Age (Ma) 121.8 - 123.8
Notes :
  1. 121.8 - 123.8 Ma is current best estimate for the Barremian-Aptian boundary (Olierook et al. 2019) Previous age constraints: 125 ± 1 Ma determined stratigraphically (Barrêmian Aptian boundary (which is itself poorly constrained in age)) (Bron and Gostin 2012) ~128 Ma estimated from stratigraphy and palynology (Gorter et al. 1989)

Method :
  1. Stratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Erosion
3
  1. Essentially uneroded but buried. Contains a record of the seismic wave on local unconsolidated sediments (Bron, 2012)
Final Rim Diameter
Unknown
Apparent Rim Diameter
66 km
  1. Recalculated diameter is ~66 km (previously 55 km) based on the measured central peak diameter of ~22 km (Gostin and Therriault, 1997).
Rim Reliability Index
2
  1. Central "dome" 22 km km diameter and metasedimentary basement uplifted at least 450 m based on correlation withwells outside crater (Gostin and Therriault, 1997).
Crater Morphology
Complex
Central Uplift Diameter
22km
Central Uplift Height
800 m
Uplift Reliability Index
3
Structural Uplift
450 m
Thickness of Seds
Target Age
Palaeozoic Mesozoic
Marine
No
Impactor Type
Other Shock Metamorphism
No
Shatter Cones
No
  1. Buried impact structure.
Planar Fractures
No
  1. PFs: In debate whether the Tookoonooka PFs are considered an impact indicator in isolation (French and Koeberl, 2010).
Planar Deformation Features
Yes
  1. PDF in quartz grains (Gorter et al., 1989).
Diaplectic Glass
Yes
  1. (Bron, 2012)
Coesite
No
Stisovite
No
Crater Fill
MB, M
  1. Because impact occurred during deposition, a widespread proximal and distal eject horizon may be preserved in the Eromanga Basin, but has not been reported (Haines, 2005). 115 m of breccia were observed 25 km SE of the central uplift. This breccias are considered to be M and MB (Gostin and Therriault, 1997). LB are observed at the base of the Wyandra Sandstone Member up to a distances of more than 10 crater radii (Bron and Gostin, 2012).
Proximal Ejecta
LB
Distal Ejecta
LB
Dykes
Volume of Melt
Depth of Melting

References

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J D Gorter, V A Gostin, P Plummer (1989) The enigmatic sub-surface Tookoonooka complex in south-west Queensland: its impact origin and implications for hydrocarbon accumulations, Proceedings of the Cooper and Eromanga Basins Conference, p. 441-456, url

V A Gostin, A M Therriault (1997) Tookoonooka, a large buried early Cretaceous impact structure in the Eromanga Basin of southwestern Queensland, Australia, Meteoritics & Planetary Science 32(4), p. 593-599, url

K A Bron, V Gostin (2012) The Tookoonooka marine impact horizon, Australia: Sedimentary and petrologic evidence, Meteoritics & Planetary Science 47(2), p. 296-318, url, doi:10.1111/j.1945-5100.2012.01330.x