Dalhousie Springs
Designation:
Australia-SA_Dalhousie_Springs
Location:
| Latitude | Longitude |
|---|---|
-26.421650° | 135.502633° |
-26.437500° | 135.501417° |
-26.455165° | 135.482594° |
Locality and ownership:
Witjira National Park
Access:
From Oodnadatta travel 100km NNW on the road to Mt Sarah. Turn east and travel 58km NE on the road to Witjira National Park
Local contacts:
Nearest services:
Mt. Dare
Risks:
Mosquitos and other insects are a major nuisance. Giant millepedes were seen at the campsite - these have a poisonous bite. At time of surveying weather conditions were very windy.
Terrain:
artesian springs
General:
Large complex of artesian springs developed in anticlinal structure of the Great Artesian Basin. The ground water is derived from deep aquifers and has travelled for long distances through the artesian basin. The waters emerge at the surface at temperatures of approximately 40 degrees. The groundwater discharge flows north and then east into the Simpson Desert as a braided stream channel complex. This is currently dry, but together with the evidence of large extinct mound springs points to large past discharges. The area is a mosaic of mound springs in varying stages of activity from extinct through to quiescient and actively flowing. Intervening areas are characterized by non-focussed ground water discharge.
Site descriptions:
- Area typical of surface between springs, patchily vegetated flat surface consisting of fawn gypsiferous silt colonized by grey pustular cryptobiotic crust and with puffy texture through crystallization of salts in the capillary fringe. The surface shows dessication cracks and patchy halite efflorescence. Sediment pedestals beneath some higher plants reveal deflation of surface. Excavations reveal that the subsurface is damp.
- Cryptobiotic pustular mat, grey in colour on upper flanks of quiesent mound spring. Soil consists of puffy gypsiferous silt, with halite efflourence on the lower slopes. Top of mound spring covered by large trees with very dense understorey of tall grass.
- Hot spring on side of active spring crest. Water discharges at approximately 40 degrees from spring approximately 1 metre deep and 1.5 metres in diameter. Water is clear and discharges at sufficient rate to feed a stream 50cm deep and approximately one metre deep. Several vents on the floor of spring discharge large bubbles at the rate of several per second. A distinctive, sulferous odour is noticeable. The spring is floored by an emerald green blistered microbial mat and locally has long filaments of green algae. Local films of ferrihydrite are present on the surface of the spring and there is an orange ferric hydroxide crust on the stream bed downstream.
- Extinct mound spring consists of a hard cap made up of horizontal slabs of hard cap grey and white fenestral limestone surrounded by eroded cone of puffy gypsiferous silt. This is a small example, less than 20 metres in extent.
Climate:
Flora and fauna:
Salt tolerant flatbush, including Old Man. Phragmytes aquatic reedgrass. Coolebah and Red Mulga trees. Field mice. Various birds. Giant millepedes.
History:
Aboriginal groups, including the Lower Southern Aranda and the Wongknurru people have made use of the springs for at least 15, 000 years.
Analogue value:
The analogue value is threefold. Firstly, the large area of groundwater discharge and resulting outflow channle provides a small scale analogue to the large outflow channels which are also believed to be supplied by ground water. Secondly, the thermal springs and associated microbial communities provide an analogue for putative Martian oasis associated with geothermal activity. Thirdly, the sulfate rich soils may offer similarities to similar salt laden Martian soils.
References:
- van Oosterzee, P. A 2000. Field Guide to Central Australia. Marleston, SA: J.B. Books.
Map reference:
Geology
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