Mount Toondina
Designation:
Australia-SA_N-Toondina
Location:
| Latitude | Longitude |
|---|---|
-27.950001° | 135.366699° |
Locality and ownership:
About 45 km south of Oodnadatta, pastoral leases.
Access:
Along an old and rehabilitated seismic line. Strictly 4WD only.
Local contacts:
Nearest services:
Oodnadatta
Risks:
The area is not rugged but is remote and difficult to access. The nearest hospital is at Coober Pedy. The area should not be visited without two vehicles and appropriate supplies of water food, and good communications and emergency procedures. The risk factors must be considered medium to high.
Terrain:
possible astrobleme, springs
General:
The geology is controversial and complex. It consists of a concentric series of uplifted deformed Palaeozoic and Mesozoic rocks capped by flat-lying Cainozoic deposits. The rocks at the centre of the uplift are highly deformed Mt. Toondina Formation (Permian) surrounded by a ring of less deformed Algebuckina Sandstone (Jurassic), and Cretaceous Cadna-owie Formation and Bulldog Shale. The Algebuckina sandstone is the main aquifer of the Great Artesian basin and discharging springs in this unit had deposited flat-lying travertines, remnants of which make up the modern topographic feature. The area of geophysical disturbance about Mt. Toondina suggests the structure is about 4 km across. The structure has been variously described as a diapir and an impact structure. An impact origin was first postulated in 1976 and immediately vigorously denied by others.
Climate:
Nearest BOM Weather Station: Oodnadatta
Flora and fauna:
Flora consists of sparse grassland and herbaceous vegetation, and scattered shrubs. Fauna is typical of inland Australia.
History:
The structure was first mapped in 1964 and periodically revisited since then. There were extensive geophysical exploration using gravity and seismic surveys, as part of a petroleum exploration program.
Analogue value:
The association of a possible astrobleme and eroded remnants of spring and lake deposits make this a good geological analogue for Mars. Resolution of the formation of Mt. Toondina would be of considerable geological interest. Visually the area is probably a passable Martian analogue The terrain is not particularly challenging for an analogue rover vehicle.
References:
- Freytag, I. B. 1965. Mount Toondina Beds - Permian sediments in a probable piercement structure. Transactions of the Royal Society of South Australia 89: 61-76. The first paper on the structure. Contains a detailed geological map.
- Plescia, J. B., Shoemaker, E. M., and Shoemaker, C. S. 1994. Gravity survey of the Mount Toondina impact structure, South Australia. Journal of Geophysical Research 89(E6): 13,167-13179. The only recent paper discussing an impact origin. Focuses mainly on how the geophysical data is inconsistent with a diapiric origin, but presents no new geological information.
- Wopfner, H. Mount Toodina, diapir of astrobleme? Quarterley Notes, Geological Survey of South Australia 62: 21-24. An attempted refutation of Youles' suggestion that Mt. Toondina was an astrobleme.
- Youles, I. 1976. Mount Toondina impact structure. Quarterley Notes, Geological Survey of South Australia 60: 10-12. The first suggestion that Mt. Toodina might be an astrobleme
Map reference:
Oodnadata 1:250,000 topographic sheet.
Geology
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