Mount Toondina crater is an impact structure (or astrobleme), the eroded remnant of a former impact crater, located in northern South Australia in the locality of Allandale Station about south of the town of Oodnadatta. Mount Toondina is the high point of a circular topographic feature rising out of an otherwise relatively flat desert area of the Eromanga Basin. An impact origin was first suggested in 1976, challenging the earlier diapir (salt dome) hypothesis,Youles I.P. 1976. Mount Toondina impact structure. Geological Survey of South Australia Quarterly Geological Notes 60, 10–12. and strongly supported by subsequent studies.Shoemaker E.M. & Shoemaker C.S. 1988. Impact Structures of Australia (1987). Lunar and Planetary Science Conference XIX, 1079–1080. Abstract A geophysical survey using gravity methods indicates an internal structure typical of complex impact craters, including an uplifted centre, and suggests that the original crater was about 3–4 km in diameter.Plescia J.B., Shoemaker E.M. & Shoemaker C.S. 1991. Gravity survey of the Mt. Toondina impact structure, South Australia. Lunar and Planetary Science Conference XXII, 1079–1080. Abstract The crater must be younger than the Early Cretaceous age of the rocks in which it is situated, but otherwise is not well dated. It has clearly undergone significant erosion since the impact event.
References
Further reading Halihan, T., Dressler, A., Love, A., Xie, Y., Simmons, C. T., et al., Numerical and hydrogeophysical model of Mount Toonsina impact crater, South Australia. (Abstract). Geological Society of America, vol. 44, pp. 535. 2012 Moorcroft, E., Geophysical investigation, Mt. Toondina area. Quarterly Geological Notes, The Geological Survey of South Australia, v. 12, pp. 3–6. 1964